POSTERS–MONDAY
Poster Session Abstracts
102nd Annual International Conference of the
American Society for Horticultural Science
Las Vegas, Nevada
Presenting authors are denoted by an astrisk (*)
The number preceeding the poster title corresponds to the
location of the poster in the Poster Hall
Poster Session 1—Postharvest Quality: Fruit
18 July 2005, 12:00–12:45 p.m. Poster Hall—Ballroom E/F
(20) Effect of Fruit Dipping into Germanium Solution Just
After Harvest on Fruit Quality of ‘Niitaka’ Asian Pear
Wol-Soo Kim1, Tae-Hyun Kim1, Soon-Ju Chung1, Hyun Suk Choi*2
1
Chonnam National University, Department of Horticulture, 300 Yongbong-dong, Gwangju,
500-757, Korea; 2University of Arkansas, 316 Plant Science, Fayetteville, AR, 72701
Germanium has been reported as a mineral element affecting plant
cell metabolism. Many trials to supply germanium to fruit have been
carried out since tests have confirmed germanium’s role as a medical
substance. Supplying germanium to orchards by soil and foliar application was not effective because of loss from rainfall. Also, tree
injection with germanium solution required the insertion of a tube to
the tree xylem at each injection site. In order to increase germanium
absorption by fruit, this study carried out the postharvest dipping of
fruit into germanium solution. ‘Niitaka’ pear (Pyrus pyrifolia) fruit
was treated with two types of germanium, GeO (inorganic type) and
Ge-132 (organic type), in a concentration of 50 mg·L–1 just after harvest
in early Oct. 2004. Flesh browning after peeling the fruit was delayed
by germanium treatment, and polyphenoloxidase (PPO) activities
were lowered. Postharvest potentials were maintained at high levels
for fruit firmness, physiological disorders, and decayed fruit during
cold storage at 0 to 1 °C for 2 months. Antioxidant and some phenolic
compounds were higher than those of control fruit.
(21) Quality Factors Important to Navel Orange Taste as
Influenced by Maturation and Handling
David Obenland*1, Paul Neipp1, Jim Sievert,2 Sue Collin,2
Mary Lu Arpaia2
1
2
USDA-ARS, San Joaquin Valley Agricultural Sciences Center, Parlier, CA, 93648;
University of California, Kearney Agricultural Center, Parlier, CA, 93648
Maturity standards that determine when navel oranges can be harvested
in California are currently based upon the ratio of soluble solids content
(SSC) to titratable acidity (TA) and the rind color of the fruit. These
standards may be inadequate to describe the quality of the fruit, which
is important given the increased competition from other commodities in
the marketplace and declining consumption of fresh citrus. To reevaluate the basis of the maturity standard, navel oranges were harvested
at intervals throughout the season and evaluated for SSC, TA, juice
ethanol concentration, percent juice, peel coloration, and sensory
characteristics. Three varieties of navel oranges, representing early-,
mid- and late-season maturities, were used. SSC : TA ratios averaged
6.3 at the beginning of the season and steadily increased to 23.4 at
the end of the season. Changes in the hedonic rating, or likeability of
the fruit taste as rated by the sensory panelists, were closely related
to the SSC : TA ratio and ratings of sweetness and tartness. These
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relationships showed a similar pattern for all of the navel varieties.
A hedonic rating of 6 (like slightly) was not reached until the SSC :
TA ratio exceeded the current legal minimum of 8:1, suggesting that
the standard should be raised. Juice ethanol levels and percent juice
did not have any apparent influence on the sensory ratings. Fruit that
were run over a packing line and waxed developed higher amounts of
ethanol during storage than control fruit but did not differ substantially
from them in hedonic rating.
(22) Evaluation of Postharvest Texture and Weight
Loss in Apple Fruits by Destructive and Nondestructive
Measurements
Sun Tay Choi*1, Judith Abbott2, Kyu Seob Chang3, Ji Gang Kim1,
Chae Il Lim1
1
National Horticultural Research Institute, Postharvest Technology Division, 475 ImokDong, Jangan-Gu, Suwon, Kyeonggi, 440-706, South Korea; 2USDA-ARS, Produce Quality
and Safety Laboratory; 3Chungnam National University, Food Science and Technology
The relation between sensory and instrumental measurements of apple
texture was investigated to find an effective postharvest texture measurement method of apple. Then nondestructive evaluation of texture and
weight loss using NIR was conducted. ‘Gala’ and ‘Fuji’ apples were
sampled during storage at 20 °C with 80% to 85% relative humidity.
Instrumental measurements included penetration, compression, and
bending tests with a texture analyzer, and sensory attributes were finger
firmness, hardness, crispness, and mealiness. The penetration test was
more effective for postharvest texture measurement than compression and bending tests in the correlation between sensory texture and
instrumental measurement. As texture evaluation parameters, elastic
modulus (slope before rupture point) and work (area to penetrate) of
penetration test were more sensitive than maximum force. Maximum
force, generally used as the parameter for texture evaluation, had a
little problem under influence of weight loss in ‘Fuji’; however, elastic modulus and work could detect the texture change of apple under
influence of weight loss as well as softening. In the investigation of
possibility of nondestructive evaluation using NIR of texture, the
MLR analysis for elastic modulus determination of penetration test
showed good correlation (R = 0.82, SEP = 2.66) in combination of two
cultivars. Also, in the weight loss evaluation, MLR analysis showed
the prediction correlation of 0.79 and SEP 1.08 in combination of
two cultivars. These results showed the possibility of nondestructive
evaluation using NIR of postharvest texture and weight loss.
(23) Sorbitol Transport, Sorbitol, and Watercore in Apple
Cultivars Differ in Watercore Susceptibility
Wayne Loescher, Tad Johnson, Randolph Beaudry*,
Sastry Jayanty
Michigan State University, Horticulture, East Lansing, MI, 48824
Sorbitol is the major carbohydrate translocated into apple fruit where it
is normally metabolized to fructose. In watercored apple fruit tissues,
however, the intercellular spaces become flooded and sorbitol content
is consistently higher than in nonwatercored apples, suggesting a
defect in sugar alcohol metabolism or transport. Our previous results
have identified and characterized two sorbitol transporters, MsSOT1
and MsSOT2, in apple fruit tissues. Sorbitol transporter gene expression has been implicated in development of watercore with MsSOT
expression diminished or absent in certain watercored fruit tissues. To
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explore this further, we have investigated the relationships between
watercore, fruit maturation, fruit composition, and MsSOT expression
in a number of apple cultivars that differ in watercore susceptibility. We
also compared transporter expression between affected (watercored)
and healthy parts of the same fruit and between watercored and nonwatercored fruits throughout the maturation and ripening processes.
The MsSOT expression was often dramatically reduced in fruit tissues
exhibiting watercore. Thus, in susceptible cultivars, maturing (ripening) fruit parenchyma cells lose the ability to transport sorbitol, and
this in turn leads to sorbitol accumulation in the apoplastic free space
and subsequent flooding of these spaces. These results are consistent
with a relationship between watercore and sorbitol transport and also
with a genetic susceptibility to the disorder.
(24) Varietal Apple Wines from Great Plains-grown
Cultivars
Patricia Lattrell1, Durward A. Smith1, Paul Read*2,
Susan S. Cuppett1
1
University of Nebraska-Lincoln, Food Science and Technology, 253 Food Industry
Complex, Lincoln, NE, 68583-0919; 2University of Nebraska-Lincoln, Agronomy and
Horticulture, 377-J Plant Science, Lincoln, NE, 68583
There is little information regarding processing methods that result
in quality and uniformity in varietal apple wines. The object of this
research was to determine if apple cultivars grown in the Great Plains
region could be used to produce premium quality single cultivar wines,
and to establish efficient processing methods that optimize quality.
The qualities of single cultivar apple (Malus ×domestica) wines were
investigated, including chemical characteristics of the apple juices,
e.g. total soluble solids, acidities, and tannin contents. Analyses were
performed on the fresh juices, fermenting juices, wines held for 6
months, and the aged wines. Fermentable sugar content was increased
either by the addition of sucrose or by the addition of concentrated
juice of the same apple cultivar. An optimized method of purge and
cold trapping injection capillary gas chromatography was applied to the
analysis of some volatile constituents. Profiles of the wine volatiles were
analyzed to determine differences among cultivars. The harsh flavors
and yeasty odors of the wines diminished after 6 months of storage.
Acidity and volatile acidity increased slightly during storage. Tannin
contents, fermentation efficiencies and volatile profiles differed among
varieties. This research indicated that some apple cultivars grown in
the Great Plains produce acceptable single cultivar wines.
(26) Commercial Film Coatings Reduce Weight Loss and
Improve Appearance of ‘Keitt’ Mango Fruits
(Mangifera indica L.)
Manuel Baez-Sañudo*, Jorge Siller-Cepeda,
Rosalba Contreras-Martinez, Laura Contreras-Angulo,
Rosabel Velez, Dolores Muy-Rangel
CIAD,A.C. Culiacan, Postharvest Physiology, Carretera a Eldorado Km. 5.5. Apdo. Postal
32-A., Culiacan, Sinaloa, 80129, Mexico
Mango ‘Keitt’ is characterized by a poor external color development
and a slightly high transpiration rate during ripening, which affect
external quality. When fruit is ripening, the peel turns from a green to
yellowish or dull green color, and the peel has no shine. We evaluated
the effectiveness of three film coatings to reduce weight loss, improve
appearance, and maintain quality during ripening of ‘Keitt’ mango
fruits. Four lots of fruits were obtained from a packinghouse in late
September and transported to the laboratory. Each lot was sprayed
at the commercial recommended rates with SemperFresh™, Natural
Shine™, TFC 210, and FreshSeal™ coatings. Water sprayed fruits
were used as a control. After applications, fruits were stored for 15
days at 22 °C and 85% RH to simulate marketing conditions. Quality
parameters evaluated included weight loss (%), firmness, external and
internal colors (hue, chroma, l), respiration rate (CO2 production), and
chemical parameters such as pH, titratable acidity and °Brix. After 15
days, fruits coated with Natural Shine reduced 50% of the weight loss
as compared to control fruits, while fruits coated with FreshSeal and
SemperFresh reduced only 1.7% and 3.5%, respectively. Firmness
declined from 155 N to 10 N during storage, being more evident on
day 10, when fruits were table ripe. Fruits treated with SemperFresh
were softer as compared with the other treatments. Titratable acidity
decreased from 0.8% to 0.2% during storage and °Brix increased
from 13 to 17–18 in all treatments. Fruit coated with Natural Shine
had reduced weight and firmness loss. Additionally, fruits developed
a better external color, with lower hue values, higher chromaticity and
luminosity, which improve fruit appearance.
(27) Peel Browning Development of Bananas Treated
with SmartFresh™ and Film Coatings Stored under Low
Humidity Conditions
Manuel Baez-Sañudo, Jorge Siller-Cepeda*,
Rosalba Contreras-Martinez, Laura Contreras-Angulo,
Rosabel Velez, Dolores Muy-Rangel
CIAD,A.C. Culiacan, Postharvest Physiology, Carretera a Eldorado Km. 5.5. Apdo. Postal
32-A, Culiacan, Sinaloa, 80129, Mexico
(25) Characterization of Volatile Biosynthesis in
‘Jonagold’ Apples (Malus ×domestica Borkh.) during the
Ripening Process
Nobuko Sugimoto*, Randy Beaudry
Michigan State University, Horticulture, Plant and Soil Science Building, East Lansing,
MI, 48824
The objective of the experiment was to determine developmental
changes in major aroma profiles in ‘Jonagold’ apple (Malus ×domestica Borkh.) and analyze climacteric fruit characteristics. Changes
in internal ethylene production, respiration, skin color, texture, and
aroma concentration were measured during maturation and ripening
of ‘Jonagold’ apple fruit. Patterns for skin color, starch, and internal
ethylene content were typical for the variety. Volatile compounds and
CO2 increased after a rapid increase in ethylene production. Total ester
emission peak coincided with fruit softening. Hexyl acetate, 2-methylbutyl acetate, butyl acetate, and hexyl 2-methylbutanoate were found
to be the major volatile compounds detected by GC/MS. Long chain
esters, such as hexyl acetate and butyl acetate, contributed during the
early stages of ripening and short chain esters such as n-propyl acetate
and butyl propanoate increased later. Esters are formed by combining
alcohol moiety with CoA derivative of fatty acid moiety by the action
of alcohol acyl transferase (AAT). The alcohols butanol, 2-methylbutanol, propanol, and hexanol increased at an earlier developmental
stage than the esters for which they acted as substrates.
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Bananas are usually harvested at the “all green” maturity stage in the
country of origin and exported to main markets. Upon arrival, fruits
are forced to ripen with ethylene and moved to market conditions to
accelerate color change and ripening. Fruits exposed to low relative
humidity conditions at market frequently induce browning of the peel
and diminish quality. To protect fruits marketed under those conditions
and to reduce peel browning, SmartFresh™ (1-MCP) alone or combined
with two film coatings was evaluated. Banana Cavendish type fruits
obtained from a warehouse at all green color stage were applied with
two film coatings: 1) SemperFresh™ (1.2%); or 2) FreshSeal™ (3 °Brix).
Additionally, a set of fruits were left as a control without coatings.
Coated and control fruits were then exposed to 150 ppm of ethylene
for 24 hours at 20 °C. When fruits reached color stage 3 (more green
than yellow), 0 and 300 ppb of 1-MCP were applied for 12 hours at
22 °C. Fruits from all six treatments were stored at 22 °C and 30%
to 40% relative humidity for 5 days to follow quality changes and
browning development. Weight loss, firmness, color, pH, acidity, °Brix
and appearance were evaluated daily. Control fruits, SmartFresh™
alone, FreshSeal™ + SmartFresh™ and both film coatings alone lost
more than 10% of weight after 5 days. Only fruits treated with SemperFresh™ + SmartFresh™ reduced weight loss below 10%. Firmness
tests indicated a higher force penetration due to dehydration of peel.
Pronounced browning was observed on control fruits. SemperFresh™ +
SmartFresh™ delayed yellow color appearance, sugar spot incidence,
and peel browning development, extending shelf-life. No significant
changes were observed on chemical characteristics.
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(135) Planttalk Colorado™: 24-hour Answers for
Gardeners
Jan-Louis Bezuidenhout*, Hannes Robbertse
James Klett*
University of Pretoria, Plant Production and Soil Science, South Africa
Colorado State University, Dept. of Horticulture and Landscape Architecture, Fort Collins, CO, 80523
Discoloration of the lenticels of some mango cultivars is a serious
problem, affecting the economic value of the fruit. Mango fruit
lenticels develop from ruptured stomata on fruit from 20 mm in ‘TA’
and ‘Keitt’ and 30 to 40 mm in ‘Kent’. Lenticels enlarge as the fruit
grow due to stretching of the fruit surface. Adult lenticels of ‘TA’
and ‘Keitt’ are larger in size than those of ‘Kent’. ‘Kent’ lenticels are
also better insulated than ‘TA’ and ‘Keitt’, having a thick cuticle in
the lenticel cavity and, in some instances, a phellogen is also present
where ‘TA’ and ‘Keitt’ lack both of the above mentioned. Resin present
in the skin of the fruit play an important role in the discoloration of
‘TA’ and ‘Keitt’ lenticels. Resin of both ‘TA’ and ‘Keitt’ fruit contain
a considerable amount of an aggressive compound termed terpenes.
These terpenes are volatile and able to move out of the resin ducts
via the sublenticellular cells to the outside of the fruit. The integrity
of tonoplasts situated in sublenticellular cells are lost due to the presence of terpenes, causing vacuolar bound phenols to come into contact
with polyphenol oxidase, present in the cell walls. The product of the
resultant reaction is a quinone, accumulating as a brownish deposit
in the cell walls, the black markings visible from the outside. This is
the spontaneous discoloration process. Lenticel discoloration may also
occur due to maltreatment, i.e., rough handling, to high temperatures,
extended period on brushes on the packline, breaking of the cold chain,
and spilling of resin onto the surface of the fruit.
(136) Survey of Landscape Influence on Spider Migration
into Homes
Poster Session 2—Consumer Horticulture and
Master Gardeners
18 July 2005, 12:00–12:45 p.m.
Carol O’Meara*
Poster Hall–Ballroom E/F
(134) “Plant Propagation” CD-ROM
1
1
2
2
Mary Welch-Keesey , B. Rosie Lerner* , Sharon Katz , Joan Crow ,
Becky Goetz2, Janie Nordstrom Griffiths3
1
Purdue University, Horticulture and Landscape Architecture, 625 Agriculture Mall Drive,
West Lafayette, IN, 47907-2010; 2Purdue University, Agricultural Communications,
615 West State Street, West Lafayette, IN, 47907-2053; 3Purdue University, formerly
Horticulture and Landscape Architecture, 625 Agriculture Mall Drive, West Lafayette,
IN, 47907-2010
“Plant Propagation” is a CD-based course that covers seed propagation, divisions, layering, cuttings, and grafting. It is multimedia at its
best—hundreds of photos, illustrations, and videos show close-up
details of each propagation method and create a fresh and enjoyable way to test the viewer’s knowledge. Although designed for the
amateur gardener, it is detailed enough to be used as a supplemental
text in college-level plant propagation courses. Additional features
include: 1) an extensive Resources section that lists additional book
and internet resources, scientific names of all the plants discussed in
the course, and sources for tools; 2) an extensive Glossary, including
audio of the correct pronunciation of 50 terms; 3) a Basics section
that reviews the different types of plant propagation, plant biology,
and horticultural concepts, such as potting media, lighting, and plant
growth regulators; and 4) a short discussion of the use of tissue culture
for plant propagation. “Plant Propagation” is available for $40 from
Purdue Extension’s online education store at http://www.ces.purdue.
edu/new/. It’s also available by calling (888) EXT-INFO or e-mailing media.order@purdue.edu. The product code is CD-HO-3.A free
preview of the course is available online at http://www.hort.purdue.
edu/plantprop/webversion/Intro.html. If you have questions about
the course content, please contact the authors directly: Mary Welch
Keesey (marywk@purdue.edu) or (317) 630-3257 and B. Rosie Lerner
(rosie@purdue.edu) or (765) 494-1311.
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final6_20July HS.indb 995
Planttalk Colorado™, established in Fall 1997, is a 24-hour toll-free
automated phone service available in English and Spanish and website
that provides gardening consumers with reliable and timely information
on a variety of horticultural and related areas topics. Planttalk Colorado™
is unique in that it is sponsored by Colorado State University Cooperative Extension, Denver Botanic Gardens and the Green Industries of
Colorado. Over 450 topics edited and approved by all entities ranging
from general gardening to emerging issues, such as new disease and
insect concerns. Recent efforts have included translation of a portion
of the scripts into Spanish to reach a larger audience and the rising
Hispanic population in the state and region. Marketing efforts have
evolved to include a website with photos and illustrations along with
linkages to other university research-based information. Other marketing tools have included: free incentives, mass media marketing,
and tabletop and banner displays for use at educational functions. A
review of phone usage vs. web hits will be discussed. Web hits averaged 92,528 monthly in 2004 vs. phone usage averaged 309 monthly
in 2004. Consumers have the ability to post comments on both web
and phone systems. They can rank the overall program on the web.
Funding is a cooperative effort between all three partners. Planttalk
Colorado™ has increased visibility to Cooperative Extension and built
partnerships with the Green Industry of Colorado and Denver Botanic
Gardens for delivering reliable and accurate information to all citizens
of Colorado and beyond.
POSTERS–MONDAY
(28) Lenticel Development and Discoloration of Some
Mango [Mangifera indica (L.)] Cultivars
Colorado State University, BioAgricultural Science and Pest Management, Longmont,
CO, 80501
Claims of disproportionate numbers of spiders in certain homes and
public demand for non-pesticide means of pest control fostered a
closer look at whether landscaping and the manipulation of yards can
have an influence on spider migration into homes. Typically, spiders
are unwanted houseguests, and homeowner concern over potential
contacts with spiders poses challenges to acceptance of these beneficial
animals. A 2-year survey was conducted to determine if the complexity
of landscaping surrounding a home influences the diversity and abundance of spiders entering houses. The survey consisted of simple and
complex landscapes in a regional area. Complexly planted yards had
significantly higher numbers of spiders and greater diversity of spider
taxa in houses, suggesting a correlation between landscape density
and spider invaders. Species data include those that are synanthropic
throughout the United States as well as species that are seasonal home
invaders. In all, 804 spiders were collected, with 26 species and 31
genera. Results of this 2-year survey will be presented.
(137) Cultivar Comparison of Heliconias for Use in Guam
James McConnell*
1
University of Guam, College of Natural and Applied Sciences, Mangilao, GU, 96923
Cultivars of heliconias were evaluated for use in Guam as a cut flower
and in the landscape. Forty-five cultivars were planted at three locations in Guam. Due to insufficient plant material, the evaluation was
preliminary. Noteworthy differences were observed among the cultivars.
Differences were noted in time to establish, frequency of flowering, and
resistance to wind damage. Establishment required large quantities of
water. Once established, some cultivars appeared to be drought-tolerant; however, feral pigs and carabao became a problem due to massive
mechanical damage. Typhoons also caused severe damage to the foliage.
Rhizomes did not suffer obvious damage, resulting in recovery within 1
year. Heliconias as a cut flower does not appear feasible. As a landscape
plant, heliconias should be given further consideration.
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6/20/05 5:00:41 PM
(138) Guam Native Trees and Shrubs for the Landscape
James McConnell*
1
University of Guam, College of Natural and Applied Sciences, Mangilao, GU, 96923
Plants native to Guam are being evaluated for use in the Guam landscape. The selected plants are being propagated by seed and/or cutting.
The genera currently being evaluated and propagated include Scaevola,
Eleaocarpus, Ochrosia, Guamia, Pemphis, and Bikkia. Variation in
flower color and floral fragrance were observed in Scaevola and selections have been made. There has been some difficulty establishing
some of the plants in the landscape environment. There have been some
significant insect problems occurring on established plants.
Poster Session 3—Nursery Crops 1
18 July 2005, 12:00–12:45 p.m. Poster Hall–Ballroom E/F
(54) Response of Betula nigra ‘BNMTF’ to Foliar and
Drench Applications of Nickel
John M. Ruter*
University of Georgia, Horticulture, Tifton, GA, 31794
Mouse ear disorder on container-grown river birch (Betula nigra L.)
is a national problem caused by a deficiency of nickel. Symptomatic
plants have leaves which are small, wrinkled, darker green, cupped,
and have necrotic margins. Research showed that mouse ear could be
cured by applications of nickel sulfate (Ruter, 2004). Further research
was needed to determine optimal rates of application for sprays and
drenches and to determine if phytotoxicity occurs at high rates. A study
was initiated at a nursery in South Georgia on 25 June 2003, using river
birch in their second growing season in #15 containers. Plants were
selected for uniformity of mouse ear disorder. Treatments included a
control, urea (0.24 g·L-1) + surfactant (1.0 mL·L-1), 250, 500, 750, and
1000 mg·L-1 nickel sulfate sprays, and substrate drenches applied at
150 and 300 mg of Ni/pot. After 30 days, all plants treated with nickel
sulfate had 100% normal growth, except the 150 mg of Ni/pot drench,
which had 79% of the canopy showing normal growth. No phytotoxicity
was noted. Plants receiving foliar sprays had a 66% to 72% increase
in leaf area, a 64% to 68% increase in leaf dry mass, a 31% to 44%
increase in stem length, and a 9% to 17% increase in specific leaf area
compared to nontreated plants. Drench treatments increased leaf area up
to 62%, leaf dry mass to 55% and stem length up to 29% over control
plants. Nickel in the foliage of nontreated plants was 2.3 mg·kg-1. For the
spray treatments, foliar Ni ranged from 5.5 mg·kg-1 for the 250 mg·L-1
treatment to 9.3 mg·kg-1 for the 1000 mg·L-1 treatment. Though plants
at the high rate of drench treatment resumed normal growth, foliar Ni
levels were not different from control plants. In general, if plants were
treated with Ni, then foliar B, Fe, and Zn decreased.
(55) Root Pruning Techniques Do Not Help Pot-bound
Plants
Jeffrey H. Gillman*1, Chad P. Giblin1, Gary R. Johnson2
1
University of Minnesota, Dept. of Horticultural Science, St. Paul, MN, 55108; 2University
of Minnesota, Forest Resources, St. Paul, MN, 55108
Plants that have been grown in containers for a long period of time
frequently develop roots that grow in circles, following the contour of
the container in which they have been planted. This condition is commonly referred to as “pot-bound.” It is considered common knowledge
that if a pot-bound plant is transplanted without any treatment, its roots
will continue to follow the contour of the now-removed container.
There are, however, a number of transplanting techniques that are
intended to reorient the roots in a direction that will be conducive to
helping roots to grow out of this potentially harmful situation. These
techniques include: butterflying, or slicing the rootball into two halves
before planting; scoring, or making inch-deep slices around the rootball
at 90° increments and an X-shaped slice across the bottom; or teasing,
where roots are manually pulled out of the shape of the container in a
direction perpendicular to the stem. Severely pot bound Salix alba and
Tilia cordata were treated with one of the three treatments previously
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listed or as a control and were transplanted into an experimental field
and grown for two full seasons. After two seasons, the trees were harvested and the number and size of roots escaping from the pot-bound
region were recorded. None of the treatments allowed roots of any size
to escape the pot-bound mass more effectively than the control.
(56) Transpiration and Photosynthesis of Grafted
Watermelon Transplants as Affected by Environmental
Factors during Graft Union Formation
Sung Kyeom Kim*1, Duk Jun Yu1, Ro Na Bae2, Hee Jae Lee1,
Changhoo Chun1
1
Seoul National University, Dept. of Plant Sciences, Seoul, 151-921, Korea; 2Seoul
National University, National Instrumentation Center for Environmental Management,
Seoul, 151-921, Korea
Grafted transplants are widely used for watermelon culture in Korea
mainly to reduce the yield and quality losses caused by soil-borne
diseases. It is normal practice to cure the grafted transplants under
high relative humidity (RH) and low photosynthetic photon flux (PPF)
conditions for a few days after grafting to prevent the wilting of the
transplants. Transpiration rate (TR) and net photosynthetic rate (NPR),
however, could be suppressed under those environmental conditions. In
the present study, TR and NPR of the grafted watermelon transplants
were compared during graft union formation under 18 environmental
conditions combining two air temperatures (20 and 28 °C), three RHs
(60%, 80%, and 100%), and three PPFs (0, 100, and 200 μmol·m-2·s-1).
Percentages of graft union formation and survival were also evaluated.
TR and NPR dramatically decreased just after grafting but slowly recovered 2 to 3 days after grafting at 28 °C. The recovery was clearer at
higher PPF and lower RH. On the other hand, the recovery of TR and
NPR was not observed in 7 days after grafting at 20 °C. Differences in
TR and NPR affected by RH were nonsignificant. Percentage of graft
union formation was 98% when air temperature, RH, and PPF were
28 °C, 100%, and 100 μmol·m-2·s-1, respectively, which was the highest
among all the treatments. Percentage of survival was over 90% when
air temperature was 28 °C and RH was higher than 80% (when vapor
pressure deficit was lower than 0.76 kPa). In addition, higher PPF
enhanced TR and NPR and promoted rooting and subsequent growth
of grafted transplants. Results suggest that the acclimation process for
grafted watermelon transplants can be omitted by properly manipulating
environmental factors during graft union formation.
(57) Bioassays and Small-scale Greenhouse Experiments
Conducted to Evaluate the Suppression of Phytophthora
cinnamomi Activity on Rhododendron × PJM ‘Elite’ by
Different Composts Incorporated into Growing Media
Jae H. Han1, George L. Good*1, Eric B. Nelson2, Harold M. Van Es2
1
Cornell University, Horticulture, Ithaca, NY, 14853; 2Cornell University, Plant Pathology,
Ithaca, NY, 14853; 3Cornell University, Crop and Soil Science, Ithaca, NY, 14853
Composts vary in their ability to suppress disease activity when incorporated into growing media. Bioassays that enable a reliable and quick
assessment of compost’s ability to suppress disease activity can save
time, funds and space. A bioassay using Lupinus × ‘Russell Hybrid’
seedlings was evaluated as a short-term test for gauging the ability of
three composts to suppress activity of P. cinnamomi. Colonized millet
seeds were prepared via the V-8 agar method. The colonized millet
seed were incorporated into the potting media at 0, 50, 100, 200, and
400 colonized millet seed/200 cc of the media used. Three composts,
including composted sewage sludge, brewer’s waste and cow manure,
were incorporated into the media (50% sand : 50% sphagnum peat, by
volume) at rates of 0%, 10%, 25%, and 50%, by volume. The media,
including the inoculated millet seed, were placed in small plastic pots
(7.6-cm-diameter and 6.7 cm high), after which 10 Lupine seeds were
sowed in each pot. Percentage of seedling loss was determined after
43 days of observation. The composted sewage sludge and the cow
manure proved suppressive at the 50% incorporation rate and the
10% and 25% rate of the latter compost. The brewer’s waste compost
proved ineffective in this regard; thus, research with this product was
discontinued. In a greenhouse study the same inoculation and compost
incorporation rates were used, but rooted cuttings of Rhododendron ×
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(58) Suppression of Phytophthora cinnamomi Activity on
Rhododendron × PJM ‘Elite’ by Two Compost-amended
Container Media under Two Irrigation Regimes and
Nursery Conditions
Jae H. Han1, George L. Good*1, Eric B. Nelson2, Harold M. Van Es3
1
Cornell University, Horticulture, Ithaca, NY, 14853; 2Cornell University, Plant Pathology,
Ithaca, NY, 14853; 3Cornell University, Crop and Soil Science, Ithaca, NY, 14853
Composted municipal biosolids were incorporated into a potting mix
containing sphagnum peat and sand (1:1 by volume) at rates of 0%,
25%, and 50%, by volume. A second medium was prepared by mixing cow manure compost in the same basic mix at rates of 0%, 10%,
and 25% by volume. Each mix was inoculated with P. cinnamomi
colonized millet seed at a rate of 200/200 cc of compost-amended
media. The potted plants were placed outdoors under nursery conditions 14 July 2003. One half of the plants were irrigated every day,
except when natural precipitation occurred; the other half was watered
once each week. Soil water potential of all treatments was measured
daily with tensiometers. Plants were harvested on 18 Aug. and 21 Oct.
2003, when the experiment was terminated. Frequent rainfall during
the period prior to the first harvest masked any impact that the irrigation treatments may have had on disease suppression. Even so, three
compost treatments proved successful in suppressing disease activity.
Between the first and second harvest dates rainfall was significantly
less frequent; thus, differences in P. cinnamomi activity between the
wet and dry regimes was noted at the 21 Oct. harvest. Under the dry
regime, all inoculated compost treatments, except the 25% municipal
biosolid compost, exhibited disease suppression based on root symptom severity and percentage of root infection. Suppression based on
shoot symptoms and percentage of shoot loss was evident only in the
50% and 25% biosolid and cow manure composts, respectively. Under
the wet regime, only one treatment exhibited suppression of disease
activity. All compost treatments held more water particularly at lower
moisture tensions. The presence of more water would tend to favor
more disease activity and not suppression.
(59) An Examination of Irrigation Volumes and
Controlled-release Fertilizer Application Methods
and Rates to Reduce Nursery Container Leachate and
Fertilizer Use
Peter Purvis, Calvin Chong*, Glen Lumis
University of Guelph, Plant Agriculture, Guelph, Ontario, N1G 2W1, Canada
Plug-rooted liners of common ninebark [Physocarpus opulifolius
(L.) Maxim.] were grown in 6-L nursery containers filled with 73%
composted pine bark, 22% sphagnum peat moss, and 5% pea gravel
(by volume). Plants were fertilized with Polyon (Nutryon) 17–5–12
(17N–2P–5K) 6-month controlled-release fertilizer at various rates
(2.5, 4.5, 6.5, and 8.5 kg·m-3) pre-incorporated, topdressed, or dibbled
(placed under the liner at potting). Plants were trickle-irrigated daily
with low (0.4-L), middle (0.8-L), or high (2.0-L) volumes of water to
maintain leaching fractions of <0.15, 0.25–0.35, or >0.60, respectively.
Regression analysis indicated that growth of ninebark increased from
30 to 109 g/plant with increasing rates of incorporated fertilizer (mean
over irrigation volumes), from 27 to 71 g/plant with topdress and from
59 to 103 g/plant with dibble. Electrical conductivity (EC, mean over
five dates) of the leachate throughout the season was highest with
dibble (0.85 dS·m-3), intermediate with incorporated (0.81 dS·m-3),
and least with topdressed (0.76 dS·m-3). With low irrigation volumes,
growth of ninebark increased from 42 to 81 g/plant with increasing
rates of fertilizer (mean over methods), and from 39 to 105 g/plant
with middle or high volumes (common regression curve). With low
irrigation volumes, leachate EC increased from 0.74 to 0.94 dS·m-3
with increasing rates of fertilizer, and from 0.75 to 0.81 dS·m-3 with
middle or high volumes.
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(60) Rooting Stem Cuttings in Compost Tea and
Anaerobic Digestion Wastewater
C. Chong*1, J. Yang1, B.E. Holbein2, R.P. Voroney3, H. Zhou4,
H.-W. Liu2
1
University of Guelph, Dept. of Plant Agriculture, Guelph, Ont., N1G 2W1, Canada; 2Super
Blue Box Recycling Corporation, Etobicoke, Ont., M8V 3Y3, Canada; 3University of
Guelph, Dept. of Land Resource Science, Guelph, Ont., N1G 2W1, Canada; 4University
of Guelph, School of Engineering, Guelph, Ont., N1G 2W1, Canada
Cuttings of sage (Salvia officinalis ‘Tricolor’), currant (Ribes aureum),
euonymus (Euonymus fortunei var. vegetus), and weigela (Weigela
florida ‘Nana Variegata’) were rooted under greenhouse conditions
(40% shade) and mist in aerated hydroponic solutions consisting of
deionized water, or mixtures of deionized water and nutrients with
various levels of electrical conductivity (EC, 0.0625, 0.125, 0.25, and
0.5 dS·m-1) from each of three sources: compost tea from municipal
solid waste; wastewater from anaerobic digestion of municipal solid
waste; and Hoagland’s (control) nutrient solution. Despite differences
in species response, rooting tended to be similar with the three nutrient sources. Euonymus rooting percentage increased linearly with
increasing EC and was similar with all three nutrient sources (common
regression curve, 61% rooting at 0.5 dS·m-1), as did root length (1.4
cm at 0.5 dS·m-1), but root number was unresponsive. Currant rooting
percent increased curvilinearly and similarly with nutrient sources
(87% calculated maximum rooting at 0.25 dS·m-1), but root number and
length were unresponsive. Sage rooting percentage and root number
also increased curvilinearly and similarly with nutrient sources (common regression curve, 100% rooting at 0.34 dS·m-1, and 4.1 roots at
0.38 dS·m-1, respectively), as did also root length with the compost tea
and Hoagland’s (common curve for these two nutrient sources, 11.0
cm at 0.30 dS·m-1), but was unresponsive to wastewater. Weigela was
unresponsive to EC or nutrient sources (mean percentage of rooting,
73; root number, 6.5; and root length, 1.9 cm).
POSTERS–MONDAY
PJM ‘Elite’ were plotted into the various treatments. Suppression of
disease activity by the composts was significant 2 and 4 months after
initiation of treatments. Significance in disease suppression noted between these treatments decreased significantly during the fifth month
of the experiment.
(61) Pot-in-pot Production of Intermountain West Native
Herbaceous Perennials
Guillermo Cardoso1, Roger Kjelgren*1, Teresa Cerny-Koenig2,
Rich Koenig3
1
Utah State University, Plants, Soils, and Biometeorology, Logan, UT, 84322; 2Washington
State University, Horticulture; 3Washington State University, Agronomy
Low water landscapes are increasing popular and important in the urban
areas of the Intermountain West (IMW). Perennial wildflowers are an
essential part of low water landscapes, and are a dominant plant type in
IMW native habitats. We compared pot-in-pot (PIP) vs. conventional
above-ground (CAG) production of six IMW native wildflower species,
Mirabilis multiflora, Aquilegia caerulea, Penstemon palmeri, Polemonium foliosissimum, Sphaeralcea grossularifolia, and Penstemon strictus
in #1 (4-L) containers. Media temperature, container-plant water loss,
stomatal conductance, and growth were measured during two production cycles per year over 2 years. Growing medium temperatures in the
PIP system averaged 10 °C cooler than in the CAG system. Consistent
with cooler growing media, overall water loss of PIP-grown plants
averaged 10% lower than plants grown in the CAG production system.
Lower growing media temperatures apparently affected transpiration,
as stomatal conductance was about 60% higher in the PIP system as
compared to the CAG-grown plants. The integrated effect of lower
growing media temperatures on plant performance resulted in about
one-third greater top and root growth for plants growing in the PIP system compared to those in the CAG system. Pot-in-pot production may
be an economically suitable nursery system for producing IMW native
perennial wildflowers by reducing water loss and enhancing growth.
(62) Field Evaluation of Various Herbicide and Mulch
Combinations for Ornamental Weed Control
Hannah M. Mathers*, Luke T. Case
The Ohio State University, Horticulture and Crop Science, Columbus, OH, 43210-1096
Two experiments were conducted at the The Ohio State University Waterman Farm, Columbus, on efficacy and phytotoxicity with evalautions
at 30, 60, 90, and 120 DAT using dry weights and visual ratings 0–10
with >7 being commercially acceptable for efficacy, and 1–10 with <3
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being commercially acceptable for phytotoxicity. The herbicide-treated
mulches and herbicide–mulch application methods were compared to
sprays of the five chemicals applied directly to the surfaces of the plots
[oryzalin (oryzalin), (AS) Surflan (aqueous solution) 2 lb/acre (a.i.),
flumioxazin (SureGuard WDG), 0.34 lb/acre (a.i.), acetochlor 76%
(Harness 2.5 lb/acre (a.i.), dichlobenil (Casoron CS) 4 lb/acre (a.i.) and a
combination of oryzalin and flumioxazin], two untreated mulches (pine
and hardwood) and a weedy. Mulches were applied untreated, over the
top of soil surfaces sprayed with the different herbicides. Mulches were
also applied untreated to untreated soil surfaces and then sprayed with
the different herbicides. Pretreated bark mulches were also evaluated
and prepared by placing the mulches on a sheet of plastic, as a single
layer thick and sprayed and allowed to dry for 48 hours. Twenty of 38
treatments gave efficacy rating of >7, pooled over all evaluation dates.
One was a direct spray, Surflan + SureGuard (7.6). Three were pretreated
mulches, Surflan + SureGuard (8.2), Harness (7.8) and Surflan (7.4)
treated pine. None of the pretreated hardwood barks provided ratings
of >7. Nine were treatments with the herbicides applied under the
bark. Seven of the nine provided ratings of >8 and only one involved
hardwood bark, Surflan + SureGuard under pine (9.1), Casoron under
pine (8.9), Surflan under pine (8.7), Harness under pine (8.3), Harness
under pine (8.0) and SureGuard under hardwood (8.0).
Poster Session 4—Genetics and Germplasm 1
18 July 2005, 12:00–12:45 p.m.
Poster Hall–Ballroom E/F
(1) Genetic Diversity of Cowpea [Vigna unguiculata
(L.) Walp.] Breeding Lines from Different Countries
Determined by AFLP Markers
Jinggui Fang1, Panchanoor S. Devanand1, ChihCheng T. Chao*1,
Philip A. Roberts2, Jeff D. Ehlers1
1
University of California-Riverside, Botany and Plant Sciences, Dept. BPS, Riverside,
CA, 92521-0124; 2University of California-Riverside, Nematology, Riverside, CA,
92521-0124
Cowpea (2n=2x=22) is a high protein, short-cycle, and essential legume
food crop of the tropics, especially in the low input agricultural areas of
sub-Saharan Africa, Asia, and South America. Lack of genetic diversity
within breeding programs can limit long-term gains from selection. The
cowpea gene pool is thought to be narrow and the genetic diversity
within breeding programs could be even less diverse. Genetic relationships among 87 cowpea accessions, including 60 advanced breeding
lines from six breeding programs in Africa and the United States, and
27 accessions from Africa, Asia, and South America were examined
using amplified fragment length polymorphism (AFLP) markers with
six near-infrared fluorescence labeled EcoR I + 3/Mse I + 3 primer
sets. A total of 382 bands were scored among the accessions with 207
polymorphic bands (54.2%). Overall, the 87 cowpea accessions have
narrow genetic basis and they shared minimum 86% genetic similarities. The data also show that the advanced breeding lines of different
programs have higher genetic affinities with lines from the same
program but not with lines from other programs. The results suggest
that there is a need to incorporate additional germplasm of different
genetic background into these breeding lines and to ensure the longterm genetic gains of the programs.
(2) A Unique Late-blight Resistance Locus from Solanum
pinnatisectum
Monica J. Norby*, Michael J. Havey
University of Wisconsin-Madison, Department of Horticulture, Madison, WI, 53706
Phytophthora infestans is the casual agent of late blight and is a major
threat to potato production worldwide. There are no curative control
agents available and resistance genes offer promise in controlling late
blight. To date, the primary source of late-blight resistance has been
from hexaploid (6x) [4 Endosperm Balance Number (EBN)] Solanum
demissum. Mexican diploid (2x) (1EBN) Solanum species possess a
wealth of late-blight resistances, but have been neglected due to crossing
barriers. Manipulation of EBN and ploidies should allow integration
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final6_20July HS.indb 998
of 2x (1EBN) germplasm into cultivated potato. Synteny between
late-blight resistance loci from Solanum species of disparate ploidies
and EBNs may facilitate the identification of unique resistance alleles
and loci. Isolate MSU96 (US8/A2) of P. infestans revealed a late-blight
resistance locus (Rpi1) from 2x(1EBN) S. pinnatisectum (PI 253214)
that mapped to chromosome seven (MGG 265:977-985). MSU96 was
also avirulent on the late-blight differential R9-Hodgson 2573 (LB3),
revealing the presence of the avirulence gene for R9 originating from S.
demissum. To test the relationship between Rpi1 and R9, we evaluated
a family segregating for R9 and revealed that it does not map to chromosome seven. The independent inheritance of R9 and Rpi1 indicates
that Rpi1 is a unique resistance locus. We are conducting a variety of
crossing schemes to introgress Rpi1 into cultivated potato.
(3) Seed Regeneration of Short-day Onion Accessions in
the U.S. Collection
Christopher S. Cramer*1, Larry D. Robertson2
1
New Mexico State University, Dept. of Agronomy and Horticulture, Las Cruces, NM,
88003; 2ARS, USDA, Plant Genetic Resources Unit, Geneva, NY, 14456-0462
Numerous short-day onion accessions maintained at the Plant Genetic
Resources Unit (PGRU) of Geneva, N.Y., were in danger of being lost
from the U.S. germplasm collection due to sub-standard viability and
low seed supply of those accessions. Seed regeneration of short-day
onions at Geneva, N.Y., has been difficult because of improper daylengths
and environmental conditions. A project was initiated in Sept. 2001
between PGRU and the onion breeding program at New Mexico State
University to regenerate 75 accessions that were in the most danger of
being lost from the collection. Even though germination rates were low
for most accessions, plants were recovered from 72 accessions. Two
accessions did not produce bulbs as it was likely they were long-day
accessions. Of the remaining accessions, two accessions produced
bulbs but did not produce seed. Several accessions bolted during bulb
production and plants were covered with crossing cages, crosses were
made, and seed was collected. Seed of 54 accessions were sent to
PGRU to be incorporated back into the collection and to become available for distribution. Seventeen accessions produced less than 35 g of
seed and were retained in order to produce additional seed in a second
regeneration step. Some of the short-day accessions that have become
available include ‘Amarela Globular Rio Grande’, ‘Babosa’, ‘Baia
Performe Sintese No. 22’, ‘Beth Alpha’, ‘Burgundy’, ‘California Early
Red’, ‘Dehydrator No. 5’, ‘Early Crystal’, ‘Eclipse L303’, ‘Imperial
48’, ‘New Mexico Yellow Grano’, ‘Pusa Red’, ‘Red Bermuda’, ‘Red
Creole’, ‘Red Grano’, ‘Red Patna’, and ‘Rio Grande’.
(4) Genotypic Variability of Iron and Zinc in Sweetpotato
Don La Bonte, Michael Courtney*
Louisiana Stata University, Horticulture Department, Julian C. Miller Hall, Baton Rouge,
LA, 70803
Sweetpotato [Ipomma batatas (L.) Lam.] is a major subsistence crop
in southern Africa, where iron and zinc deficiency in humans is an
important health problem. A cultivar of sweetpotato that is suited for
subsistence farming in this region and that is high in iron and zinc could
be an important means of combatting these deficiencies. As part of a
program of the International Potato Center (CIP) to develop such a
cultivar, we are working to identify the high and low range of iron and
zinc in sweetpotato cultivars grown throughout the world by testing a
number of cultivars for these nutrients. Subsidiary objectives include
determining the heritability of iron and zinc levels and surveying the
variability in the levels of these nutrients from root to root on the same
plant, from plant to plant of the same cultivar, from the proximal to the
distal end of a given root, and from cambium to cortex.
(5) A Comparative Study of SRAP, AFLP, and SSR
Markers for Detecting Genetic Differences among Elite
Broccoli Inbreds
Anna Hale*, Mark W. Farnham
USDA/ARS, U.S. Vegetable Laboratory, Charleston, SC, 29414
Private and public vegetable breeders are interested in using current
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(6) Highly Polymorphic Genes in Cultivated Tomato
Angela Baldo*, Larry Robertson, Joanne Labate
USDA ARS, Plant Genetic Resources Unit, Cornell University, Geneva, NY, 14456
Cultivated tomato varieties are genetically extremely similar. We identified 764 Unigenes with potential single nucleotide polymorphisms
(SNPs) among more than 15 cultivars from public expressed tomato
data. By sequencing regions from 53 of these Unigenes in two to three
cultivars, we discovered an unexpected wealth of nucleotide polymorphism (62 SNPs and 12 indels in 21 Unigenes). This included a high
proportion of predicted nonsynonymous nucleotide (17 of 33 SNPs
in exons) and nonconservative amino acid (6 of 16 nonsynonymous
SNPs) changes. We hypothesize that five of these regions are associated with introgressions from wild relatives. Identifying polymorphic,
expressed genes in the tomato genome will be useful for both tomato
improvement and germplasm conservation.
income from fresh vegetable exportations to the United States, fresh
vegetable production is a very important industry in Sonora. In fact,
growing summer vegetables for exportation during the wintertime in
Sonora, Mexico, is a good business.
(180) Effects of Plant Density on Pickling Cucumber Fruit
Quality
Mathieu Ngouajio*, Erin C. Hill, William Chase
Michigan State University, Horticulture, East Lansing, MI, 48824
Cucumber is an important vegetable in Michigan, where it is grown for
slicing (fresh) or processing. Michigan is the top producer of pickling
cucumbers in the United States, with over 27% of the total national
production. Studies were conducted in 2004 to test the effects of plant
density on cucumber fruit quality. Cucumber var. ‘Vlaspik’ was seeded
in 30.5, 45.7, 61.0, and 76.2 cm rows with 12.7 cm spacing between
plants inside the row, corresponding to final plant populations of 258,
172, 129, and 103 thousand plants/ha, respectively. The experiment used
a randomized complete-block design with 4 replications and four rows
per plot. At harvest, 10 fruits of grade 2 were randomly selected from
each plot for measurement of specific gravity, firmness, soluble solids,
color, and seed size. Cucumber fruit specific gravity, soluble solids, and
seed size were not affected by plant population size. However, fruit
firmness and color varied with plant density. Low plant populations,
when compared to high populations, produced darker green fruits, a
desired trait in pickling cucumber production. On a scale of 0 (yellowish) to 5 (dark green), plants grown under a population of 258 thousand
plants/ha scored an average of 2.8. The score was 4.6 for fruits produced
in plots with 103 thousand plants/ha. Low plant populations increased
fruit firmness as measured by a puncture test. Fruit firmness was 89,
93, 97, and 95 g·mm-2 for 258, 172, 129, and 103 thousand plants/ha,
respectively. Results suggest that cultural practices may affect pickling
cucumber fruit quality.
POSTERS–MONDAY
and emerging PCR-based marker systems in their respective improvement programs. However, before new systems are employed to
replace existing ones, the new systems must prove to be efficient and
cost-effective alternatives. Sequence related amplified polymorphisms
(SRAPs), amplified fragment length polymorphisms (AFLPs), and
simple sequence repeats (SSRs) were compared for their ability to
differentiate individuals of a diverse group of 24 elite broccoli (Brassica oleracea L. italica) inbreds. Genomic DNA was assayed using 24
AFLP, 24 SRAP, and 44 SSR primer pairs. In this assessment, SSRs
produced an average of only two bands per primer, with 25% of these
bands being monomorphic, and the remaining bands detecting very few
differences among the inbreds. Although the AFLP method resulted in
a lower rate (63%) of polymorphism than the SSRs, it produced about
20 bands per primer. SRAPs produced an average of 14 bands per
primer, with 82% of these bands being polymorphic. Since AFLP and
SRAP markers had a higher multiplex ratio and SSRs were frequently
monomorphic, AFLP and SRAPs were more effective in differentiating
the elite broccoli inbreds examined in this study. Similarity matrices
were generated from the AFLP and SRAP data, and resulting dendographs were compared.
(181) Effect of Mulch, Mycorrhizal Inoculation, and
Surround on Late Fall Pepper Production
Donald J. Makus*
1
Poster Session 5—Vegetable Crops Management–
Cropping Systems 1
18 July 2005, 12:00–12:45 p.m. Poster Hall–Ballroom E/F
(179) An Overview of the Sonoran Vegetable Industry
Everardo Zamora*, Jose Cosme Guerrero, Santiago Ayala
Universidad de Sonora, Agricultura y Ganadería, Luis Encinas, Hermosillo, Sonora,
83000, Mexico
Sonora, Mexico, is an outstanding area for growing good quality and
high-yield vegetables, fruits, and nuts for year-round exportation.
Each year, Sonora produces important, large quantities of fruits and
nuts for exportation, including table grape, citrus, pecan, and olive
fruit. Also, fresh vegetable production in Sonora is very important.
Annually, large volumes of melon, pumpkin, summer squash, chili,
husk tomato, tomato, and asparagus are produced for exportation to the
United States, Europe, and Japan. Throughout the year, two important
growing seasons for vegetable production have been established in
Sonora. The most important growing season for vegetable exportation
in Sonora is the autumn-winter season, when higher prices are reached
for summer vegetables in the U.S. markets. The autumn–winter season begins in August and finishes in December. In Sonora, during the
2002–03 agricultural cycle, 39,666 ha (89,000 acres) of vegetables
were established in the field. Many growers in Sonora are investing
in imported high technologies for protected cropping from several
developed countries, such as the United States, Canada, Israel, and
some European countries. Currently in Sonora, high technology is applied by growers for vegetable production, i.e., plastic mulching, low
and high tunnels, greenhouses, and shadow frames, which have been
frequently used on fresh vegetable commercial production to improve
both quality and yield. Because of a large labor force and the attractive
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USDA, ARS, Integrated Farming and Natural Resources Unit, Weslaco, TX, 78596
Four week-old pepper (Capsicum annuum) cultivars Sonora Anaheim
and Capistrano were transplanted on 7 Oct. 2004 into a sandy loam soil
near Weslaco, Texas (lat. 26°08’N). Plants were subject to eight treatments consisting of sweet sorghum mulch, mycorrhizal (Bio Organics)
inoculation, kaolin (Surround) application and their factorial combinations. Mulch was applied at 2.4 kg·m-2 and kaolin weekly at 25 kg·ha-1.
Mulch applications reduced soil temperatures at 5 cm typically 8 °C
during the 1200–1800 HR period of the day during the first 14 days after
planting, but decreased soil temperatures to less than 2 °C by 22 Dec.
Volumetric soil moisture content at 0–20 cm was initially 4% (absolute)
higher in the mulch treatments during the first week after planting but
deceased with time as the mulch deteriorated. Mulching increased root
dry weight 70 days after transplanting. Mycorrhizal association was
evaluated in four treatments, where incidence of mycorrhizal infection
was “mulch + mycorrhizae” > “mycorrhizae only” = ‘“mulch only”
>> “control.” Kaolin reduced plant height, plant top fresh weight, and
improved yield in both cultivars by increasing earlier flowering and,
in the case of ‘Sonora Anaheim’, reducing fruit drop caused by pepper
weevil (Anthonomus eugenii). In both cultivars, mulch reduced yields
and mycorrhizal inoculation gave no agronomic benefit.
(182) Delayed Planting and Plug Cell Volume Effects on
Growth, Development, and Yield of Transplanted Sweet
Corn
Sandra Menasha, Milton Tignor*, David Heleba
The University of Vermont, Plant and Soil Science, Burlington, VT, 05405-0082
Transplanting sweet corn is commonly practiced in the northeast U.S.
to improve stand establishment and promote early harvest. However,
early spring storms and labor constraints can delay transplanting when
establishment is most desirable. ‘Temptation’ sugary enhanced (se)
sweet corn transplants 0-, 2-, 4-, 6-, and 8-days-old beyond the “grower”
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2-week growth period were field planted to explore the effects delayed
planting combined with plug cell volume differences would have on
transplant ear quality and early yields. The transplant treatments were
evaluated in a two-way factorial (five delayed planting dates × three
plug volumes) arranged in a split-plot design with five replications.
Field sites were the whole plot treatment and the factorial treatments
were the split-plots. All transplants were planted on 24 May 2004 at the
two field sites. The final density was ≈22,000 plants/acre. Transplant
cell volume (15, 19, and 29 mL) had no significant effect on ear quality and total marketable yield. Ear length was significantly affected by
field site (P ≤ 0.0001) and ear diameter was significantly affected by
planting delay (P = 0.0145). Field site (P ≤ 0.0001) and planting delay
(P = 0.0090) both significantly affected the number of early marketable
ears/acre. The results indicate that transplants can remain in the plug
cells up to 20 days (2 weeks + 6 day delay) before the delay negatively
impacts ear diameter, tip fill, and early marketable yield.
(183) Effects of Colored Plastic Mulches on Tomato
Growth and Yield
Maurice Ogutu*
University of Illinois at Urbana-Champaign, Extension, Countryside, IL, 60525
Different colored plastic mulches can influence tomato (Lycopersicon
esculentum L.) growth and yield. A study was carried out to compare the
effects of different colored plastic mulches and bare ground on growth
and yield of tomato. Ten treatments, namely, control (bare ground),
and plastic mulches (black smooth, red, black embossed, blue, olive,
yellow, clear, white, and reflective) were replicated four times in a randomized complete-block design. Tomato variety ‘Sunstart’ seeds were
planted in flats filled with Jiffy Mix in a greenhouse in late Apr. 2004
and seedlings transplanted in early June 2004. The seedlings planted in
white and reflective plastic mulches were taller than seedlings planted
in black smooth, black embossed, clear, blue, red, and olive mulches
by 24 July 2004. Weeds were growing underneath clear, yellow, and
red plastic mulches, and squash bugs were observed in yellow plastic
mulch treatment on 2 July. Cumulative marketable tomato yield was
highest in plants grown in reflective and white plastic mulches, and
lowest in plants grown in yellow plastic mulch. Marketable fruits from
plants grown in reflective and white mulches were larger than fruits
from other treatments. In comparison with black embossed plastic
mulch, plants grown in reflective and white plastic mulches had 2 and
1.2 tons/acre higher marketable yields, respectively, than plants grown
in black embossed plastic mulch.
(184) Effects of Colored Plastic Mulches on Muskmelon
Growth and Yield
Maurice Ogutu*
University of Illinois at Urbana-Champaign, Extension, Countryside, IL, 60525
Colored plastic mulches can influence muskmelon (Cucumis melo L.)
growth and yield. A study was carried out at the St. Charles Horticulture
Research Center, St. Charles, Ill., to compare the effects of different
colored plastic mulches on vine length and yield of muskmelons. An
experiment was carried out with 10 treatments, namely, control (bare
ground), and plastic mulches (black smooth, red, black embossed, blue,
olive, yellow, clear, white, and reflective) in a complete randomized
block and replicated four times. Muskmelon variety ‘Athena’ seeds
were started in the greenhouse in late Apr. 2004 in flats filled with
Jiffy Mix, and transplanted in mid-May 2004. Seedlings planted in
black embossed, olive, red, blue, and white plastic mulches had longer
vines than seedlings transplanted in black smooth, reflective, clear,
and yellow mulches by 24 July. Seedlings planted on the control (bare
ground) had much shorter vines compared to seedlings in other treatments. The cumulative fruit number and weight was higher in blue,
olive, red, and black embossed plastic mulches than in plants grown
in clear, yellow, and reflective plastic mulch treatments. Plants grown
in white and reflective mulch treatments had larger fruits than plants
in other treatments. In comparison with black embossed plastic mulch,
plants grown in blue, olive, and red plastic mulches had higher fruit
number and yields.
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(185) Response of Vegetable Crops to Mycorrhizal
Inoculation in a Calcareous Soil in the Tropics
Mari Marutani, Joseph Tuquero, Robert Schlub, James McConnell*
University of Guam, College of Natural and Applied Sciences, UOG Station, Mangilao,
GU, 96923
The effects of a vesicular–arbuscular mycorrhizal fungus, Glomus
aggregatum inoculation were examined on growth of vegetable crops
in pot culture and field experiments with Guam cobbly clay loam soil
(clayey, gibbsitic, nonacid, isohyperthermic Lithic Ustorthents). In pot
experiments, the growth response of yard-long beans (Vigna unguiculata
subs. sesquipendalis), sweet corn (Zea mays), watermelon (Citrullus
lanatus), cucumber (Cucumis sativus), okra (Abelmoschus esculentus),
green onion (Allium fistulosum), eggplant (Solanum melongena), and
papaya (Carica papaya) were significantly improved with mycorrhizal
inoculation. A pot experiment was also conducted to evaluate effects
of G. aggregatum inoculation on the growth of corn seedlings at four
different water regimes. Seedlings inoculated with G. aggregatum
significantly improved the plant growth and the mineral uptake at all
levels of water treatments. In the first field trial, prior to seed sowing
the media in seedling trays were either inoculated or not inoculated
with G. aggregatum. Treated watermelon and eggplant seedlings were
transplanted in field. It was found that inoculating seedlings did not
improve the harvest yield of two fruit-bearing crops. The second field
experiment was conducted to study G. aggregatum inoculation and
different levels of inorganic fertilizer application on growth of corn.
Mycorrhizal colonization had positive effects on corn development and
uptake of some minerals such as Fe. Experiments in the study suggested
potential uses of a mycorrhizal fungus in an alkaline soil in the tropics.
(186) Vegetable Yields under Sustainable Production Systems
Greg D. Hoyt*
1
North Carolina State University, Dept. of Soil Science, Mtn. Hort. Crops Res.& Ext.
Center, Fletcher, NC, 28732
This experiment was designed to compare best management practices
for conventional and conservation tillage systems, chemical IPM vs.
organic vegetable production, and rotation effect on tomatoes. Four
vegetables were grown under these management practices with peppers (first year), yellow squash and fall broccoli (second year) on half
of the field plots and tomatoes on the other half. For the third year,
both sections of the field plots were tomatoes. The treatments were: 1)
conventional-tillage with chemical-based IPM; 2) conventional-tillage
with organic-based IPM; 3) conservation-tillage with chemical-based
IPM; 4) conservation-tillage with organic-based IPM; and 5) conventional-tillage with no fertilizer or pest management (control). This poster
describes pepper, yellow squash, fall broccoli, and tomato yields from
the various treatments over the 3-year rotation. These results are for
the third rotation sequence (years 79). Pepper yields were higher in
treatments with chemical fertilizer and pest control. Fall broccoli yields
were in the order: strip-tilled-chemical ≥ strip-till-organic ≥ conventional-tilled-chemical ≥ conventional-tilled-organic ≥ control. Yellow
summer squash yields were in the order: conventional-tilled-chemical ≥
conventional-tilled-organic ≥ strip-till-chemical ≥ strip-tilled-organic ≥
control. Tomato yields were in the order: conventional-tilled chemical
≥ strip-till-chemical ≥ conventional-tilled-organic ≥ strip-tilled-organic
≥ control for each of the 3 years.
Poster Session 6—Propagation 1
18 July 2005, 12:00–12:45 p.m. Poster Hall–Ballroom E/F
(168) Long-term Growth of Live Oak from Seed or Cutting
Yin-Tung Wang1, Genhua Niu*2
1
Texas A&M University System, Horticultural Sciences, Texas Agricultural Experiment
Station Weslaco, TX, 78596; 2Texas A&M University System, Horticultural Sciences,
Texas Agricultural Experiment Station, El Paso, TX, 79927
Live oak trees raised from acorns are highly non-uniform and many
produce numerous undesirable rhizomic shoots. The objectives of this
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(169) Root Formation on Stem Cuttings of Yellowflowered Cultivars of Magnolia Is Influenced by Timeafter-budbreak and IBA
Jyotsna Sharma*, Gary Knox, Maria Ishida
1
University of Florida, Environmental Horticulture, Quincy, FL, 32351
We propagated six yellow-flowered cultivars of Magnolia vegetatively
by applying 0, 8, 16, or 30 g·kg-1 indole-3-butyric acid (IBA) in talc
to bases of terminal stem cuttings collected 5, 7, 9, or 11 weeks after
budbreak. Mean rooting percentage increased from 12% (in the absence
of IBA) to 34% (after applying 30 g·kg-1 IBA). Rooting percentage also
increased with increasing basal caliper (r2 = 0.25; P < 0.0001) of a cutting.
For each collection date, more cuttings of ‘Ivory Chalice’ and ‘Yellow
Lantern’ developed roots than did other cultivars. When data were analyzed separately for selected cultivars, 63% rooting was observed among
cuttings of ‘Ivory Chalice’ collected 7 weeks after budbreak. Rooting
percentage was higher (22%) among cuttings of ‘Hot Flash’ collected
5 or 7 weeks after budbreak in comparison to later collection dates, but
harvest date did not influence rooting, which ranged from 44% to 59%,
among cuttings of ‘Yellow Lantern’. Collection of stem cuttings early
in the growing season (5 weeks after budbreak) was beneficial (31%
rooting) for inducing root formation among cuttings of ‘Golden Sun’.
We conclude that ‘Ivory Chalice’ and ‘Yellow Lantern’ are promising
choices for growers interested in clonal propagation of yellow-flowered
cultivars of Magnolia. To maximize rooting, terminal cuttings should
be collected within 5 to 11 weeks after budbreak and should be treated
with 16 or 30 g·kg-1 IBA in talc. Early collection dates improved rooting
frequencies among cuttings of other cultivars but these, particularly
‘Butterflies’, remain variably recalcitrant and merit further study.
(170) Scion Bud Removal Delays Leaf Development, But
Decreases Graft Success in Pecan Four-flap Graft
Patrick Conner*
1
University of Georgia, Horticulture Department,Tifton, GA, 31793-0748
Pecan is a highly heterozygous outcrossing species that is normally
propagated by grafting or budding onto seedling rootstocks. The
four-flap or banana graft is commonly used by growers or researchers
because of its high percentage of success, especially when employed by
novice grafters. We removed scion buds before grafting in an attempt
to delay budbreak, thus providing more time for vascular connections
to form before leaf development and its associated demand for water
takes place. Removal of buds from the scion wood was successful in
delaying bud and leaf development, but did not increase graft success,
and in one treatment actually lowered graft success.
(171) Auxin Affects Adventitious Rooting of Snowbells
(Styrax L.)
Jason J. Griffin*1, F. Todd Lasseigne2
1
Kansas State University, Dept. Horticulture, Forestry and Recreation Resources, John C. Pair
Horticultural Center, Haysville, KS, 67060; 24325 Pickwick Dr., Raleigh, NC, 27613
The snowbells (Styrax L.) are a group of flowering shrubs and trees
distributed throughout the warm-temperate regions of the northern
hemisphere. In all, there are about 120 species, of which only Styrax
japonicus Sieb. & Zucc. (Japanese snowbell) and its cultivars are
currently of commercial significance. Other species may also posses desirable horticultural traits that could be valuable on their own
merit, or used in plant improvement programs. Currently there is
little information regarding asexual propagation of the lesser known
species. The results herein show that propagation of a diverse collection of Styrax (15 taxa) is possible by stem cuttings. However,
species and cultivars within a species do not respond to auxin treatment similarly. The percentage of rooting of many taxa was improved
when cuttings were treated with 3000 or 8000 ppm (0.3% or 0.8%) of
the potassium salt of indolebutyric acid (K-IBA). However, rooting
was unaffected by K-IBA treatment in some taxa, while rooting was
negatively affected by K-IBA in others. Additionally, the number of
roots produced per rooted cutting were affected by K-IBA treatment.
In some instances, K-IBA increased the number of roots per rooted
cutting. However, in most of the taxa, root number was unaffected.
POSTERS–MONDAY
study were to 1) compare the growth rates between (Quercus virginiana
Mill.) trees from seed and cutting in four production systems and 2)
determine if trees from cuttings produce rhizomic shoots. Rhizomic
shoot cuttings 25–30 cm long were taken from a single tree about 50
years old in late Aug. 1990, rooted, and planted in 2.6-L pots after 2
months. During the same week, acorns were collected from the same
tree and germinated. All trees were planted into 13-L pots in July 1991
and then to a field in July 1992. Trees from both sources were planted
either directly in the ground, in 36.6- or 45.7-cm-diameter polypropylene fabric bags buried in the ground, or in 13-L pots on the ground.
Trunk circumference 10 cm above the soil line was roughly measured
yearly between 1992 and 1999. Initially, trees from cuttings grew
slightly slower than seedlings, having a smaller trunk circumference,
diameter, and cross-sectional area. These differences diminished and
all trees had similar circumferences after 1996. In 1992, trees in 36.6cm bags and pots had more growth than trees in the ground. In 1993,
trees in pots had better growth than those in the ground. After 1993, all
trees had similar circumferences until the end of this study, probably
due to roots extending beyond the bags and pots into the surrounding
soil. About one-third of the seedling trees produced rhizomic shoots,
whereas none of the trees from cuttings did. The rhizomic shoots of
trees in pots were contained within the pot and none from the ground.
Another significance of this research is that the cloned trees from cuttings were extremely uniform in growth habit and form.
(172) The Influence of Environment, Media, and Zerotol
on Forcing and In Vitro Establishment of Softwood
Shoots from Large Stem Segments of Acer saccharinum
and Fraxinus pennsylvanica
Faheem Aftab1, Katayoun Mansouri2, John E. Preece*2
1
University of the Punjab, Department of Botany, Q.A. Campus, Lahore, 54590, Pakistan;
Southern Illinois University, Plant, Soil and Agricultural Systems, Carbondale, IL, 62901
2
The objectives of this research were to study the effects of three environments (lab, mist, or fog), four media treatments [perlite, vermiculte,
1 perlite : 1 vermiculite (by volume), or a control (empty flats)] and
zerotol treatments on shoot forcing and subsequent transfer of explants
to in vitro conditions. Stem segments from field-grown trees were cut
to 40-cm lengths before being placed in flats with the media treatments.
Half of the flats under mist and fog were drenched weekly with zerotol
(0.18% H2O2). In a separate study, silver maple was forced under mist
and drenched weekly with zerotol at 0%, 0.09%, 0.108%, 0.135%,
0.18%, 0.27%, or 0.54% H2O2. Shoots (≥5 cm) were harvested and nodal
and shoot tip explants were surface disinfested and placed in vitro on
DKW medium with 10-8 M thidiazuron plus 1.0 μM indolebutyric acid.
Species did not interact with environment, media, or zerotol treatment,
and silver maple produced a mean of 6 shoots per stem segment, while
green ash produced a mean of 1.2 shoots. There was a significant interaction among perlite, vermiculite and environment, with the most shoots
(6.7/stem segment) produced under mist in the perlite : vermiculite mix.
Silver maple explants from the lab had only 4% microbial contamination, whereas 68% of explants from fog and 92.2% of explants from
mist were contaminated. When forcing was under fog, in perlite, and
drenched with zerotol, explants had a 43% rate of contamination. In a
separate study, when silver maple stems were placed under mist and
drenched weekly with 0.18% H2O2, 46% (18 of 39 explants) established cleanly in vitro. Contamination was higher with misted explants
that were drenched with higher or lower concentrations of zerotol.
Poster Session 7—Ornamental Plant Breeding
18 July 2005, 1:15–2:00 p.m.
Poster Hall–Ballroom E/F
(234) Self-incompatibility in Pink Tickseed, Coreopsis
rosea Nutt.
Marietta Loehrlein*1, Sandy Siqueira2
1
Western Illinois University, Agriculture, Macomb, IL, 61455; 2Stellenbosch University,
Botany, Matieland, 7602, South Africa
Coreopsis rosea is important as a landscape plant and is of some impor-
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tance for restoration of native species. In both situations it is important
to understand the breeding system so that the pollination process may
be controlled for optimal seed production. The study of the incompatibility system is important to seed production. In commercial crops,
seeds may be products of open pollination or F1 hybrids. In the former,
genetic variability exists. In conservation and recovery programs of
local flora, seeds with genetic variability are desirable. In development
of commercial crops, uniform seeds and plants are desirable. Regardless
of whether seeds will ultimately be used for commercial crops or for
species restoration, an understanding of self-incompatibility will allow
the pollination process to be manipulated for optimal seed production.
The purpose of this research was to investigate the sexual reproduction
mode in Coreopsis rosea. The objectives were to determine whether
Coreopsis rosea operates with a self-incompatibility system, and, if
so, to discover whether it is a sporophytic or gametophytic mode. The
sporophytic form of self-incompatibility has been found in other plants
in the Asteraceae family, but no one has studied self-incompatibility
in Coreopsis rosea. The purpose of this research was to identify the
self-incompatibility system in Coreopsis rosea. A series of self- and
cross-pollinations were made in situ, and in vivo pollinations were
made and the pistils studied under the microscope. Results indicate
that Coreopsis rosea is self-incompatible and operates under the
sporophytic mode.
(235) Genetic Diversity Analysis of Five Passiflora
Genotypes
Eric Stafne*, Jon Lindstrom, John Clark
University of Arkansas, Horticulture, 316 Plant Sciences, Fayetteville, AR, 72701
Passiflora is an important ornamental genus, mainly within tropical
zones. However, two cold-hardy, North American Passiflora species
exist. Previous work has been done to incorporate these species into
breeding programs with some success. The intent of this study was to
evaluate the extent of genetic diversity among five different Passiflora
genotypes, including the two native North American species, P. incarnata L. and P. lutea L. Results indicate low genetic similarity among all
genotypes with none at 50% or greater. P. incarnata and the ornamental
cultivar ‘Lady Margaret’ displayed the highest relationship at 49%. P.
incarnata averaged 35.5% similarity with the other genotypes and P.
lutea was 29.5%. Average overall similarity among all genotypes was
31.1%. These and other results show that the Passiflora genus has a
high degree of genetic variation and breeding efforts could expand
interest within North America.
(236) Evaluation of Styrax japonicus for Time of Budbreak
and Susceptibility to Spring Freeze Damage
Sandra Reed*
USDA-ARS, Floral and Nursery Plants Research Unit, McMinnville, TN, 37110
Japanese snowbell (Styrax japonicus Sieb. & Zucc.) is an outstanding
small ornamental tree that is underutilized in the United States. Many of
the cultivars of this Asian native frequently suffer spring freeze damage,
especially when grown in the areas of the country that routinely experience dramatic fluctuations in late winter and early spring temperatures.
The objectives of this study were to determine if there was variability
within S. japonicus for time of budbreak and if this variability could
be used for selecting plants with reduced susceptibility to spring freeze
damage. In 1998, 224 open-pollinated seedlings were planted in the
field. Percent budbreak was evaluated weekly during a 6-week period in
Spring 1999 and 2000. While weather conditions varied greatly between
the 2 years, there was good consistency between mean budbreak ratings
in 1999 and 2000. There was a 4-week difference between the earliest
and latest plants to break dormancy. Based on the 1999 and 2000 data,
28 plants were selected and propagated. A replicated trial involving these
selections and three cultivars was carried out in 2002, 2003, and 2004.
All of the selections broke bud later and suffered less freeze damage
than ‘Emerald Pagoda’ and ‘Carillon’, but many performed similarly
to ‘Pink Chimes’. Variation in height, width, caliper, and canopy shape
was observed among the selections. There is an opportunity to utilize
the genetic variability in S. japonicus for developing cultivars with
reduced susceptibility to spring freeze damage.
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(237) Hybridization of Hydrangea arborescens and
H. involucrata
Keri Jones*, Sandra Reed
USDA-ARS, Floral and Nursery Plants Research Unit, McMinnville, TN, 37110
Hydrangea arborescens L., or smooth hydrangea, is a shrub native to
the eastern United States that produces large corymbs of pure white
flowers in early summer. Rated as hardy to USDA cold hardiness zone
4, it is one of the most cold-hardy members of the genus. Hydrangea
involucrata Sieb. is an Asian species that produces lavender-blue
flowers in midsummer. This species, which is not widely cultivated in
the United States, is only rated as hardy to zone 6 to 7. The objective
of this study was to hybridize H. arborescens and H. involucrata for
the purpose of combining cold hardiness and flower color. Reciprocal
crosses were made between H. involucrata and H. arborescens during
Summer 2003. No seed were obtained when H. involucrata was used as
the maternal parent. Approximately 500 seeds were collected from H.
arborescens × H. involucrata hybridizations, 36 of which germinated.
Several of these seedlings were extremely weak and died at a young
age. The remaining eight plants have not flowered and all possess reduced growth rates. Hybridity was verified using RAPD markers and
morphological comparisons of hybrids and parents.
(238) The Inheritance of Blue Flower Color in
Phalaenopsis pulcherrima
Robert J. Griesbach*
1
U.S. National Arboretum, Floral & Nursery Plants Research, USDA, ARS, BARC-W,
Beltsville, MD, 20705-2350
Flower color results from the interaction of a pigment (anthocyanin)
with a co-pigment (usually a flavonone or flavonol) at a specific pH.
At more alkaline pHs (pH 5 to 6), an anthocyanin/co-pigment complex
is blue; while at more acidic pHs (pH 3-4), the same anthocyanin/copigment complex is red. In Phalaenopsis pulcherrima, a mutation in
pH resulted in a bluer flower color. The difference in pH between the
normal-colored magenta flowers (pH 5.8) and mutant violet flowers
(pH 5.5) was due to a single co-dominantly inherited gene.
(239) Genetics, Anatomy and Biochemistry of Flower
Color in Anagallis monelli (L.) ‘Pimpernel’
Andrea Quintana*1, Jana Albrechtova2, Tom Davis3, Robert J. Griesbach4, Rosanna Freyre1
1
Univ. of New Hampshire, Plant Biology, Durham, NH, 03824; 2Charles University, Plant
Physiology, Vinicna 5, Prague 2, 128 44, Prague, Czech Republic; 3Univ. of New Hampshire,
Plant Biology, 46, Durham, NH, 03824; 4U.S. National Arboretum, U.S. Department of
Agriculture, Agricultural Research Service, Floral and Nursery Plant Research, Beltsville,
MD, 20705-2350
Wild Anagallis monelli has blue or orange flowers. Hybrids with red
flowers were developed at the Univ. of New Hampshire. Orange is due
to pelargonidin, but delphinidin and malvidin can also be present; red
is due to delphinidin and malvidin; and blue is due to malvidin only. In
this study, blue and orange wild diploid accessions were used to develop
four F2 populations (n = 46 to 81). In three populations, segregation
ratios supported a previously proposed three-gene model for flower color
in this species (P > 0.01). In the fourth population, white flower color
was obtained in addition to blue, orange, and red. Molecular studies
of genes in the anthocyanin pathway using a candidate gene approach
are in progress. In a separate F2 population, blue, violet, lilac, and red
flower colors were obtained. One hybrid per color was studied on three
replicate plants. Cells with vacuoles containing anthocyanins in upper
and lower petal epidermis peels were counted in five flowers per clone
using light microscopy (M = 200×). Blue and red hybrids had mostly
blue and red cells, respectively, on both surfaces. Lilac and violet hybrids
included cells that were blue and intermediate (containing both red and
blue) on both surfaces, and also had red cells on the lower epidermis
only. Violet hybrids had more blue cells on the upper epidermis than
the lilac hybrids. Anthocyanins were determined by HPLC for each
petal epidermis in the four flower colors. The blue hybrid had only
malvidin in both upper and lower epidermis, and the red hybrid had
mainly delphinidin in both surfaces. Lilac and violet hybrids had small
amounts (2% and 2.5%, respectively) of delphinidin on upper surfaces,
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while lower surfaces had 25% to 33% delphinidin.
Zhanao Deng*, Brent Harbaugh
University of Florida, Gulf Coast Research and Education Center, Wimauma, FL, 33598
Caladiums (Caladium ×hortulanum) are ornamental aroids often forced
in containers or grown in the landscape for their colorful leaves. The
aesthetic value of caladium plants is largely determined by their leaf
characteristics. Caladium breeding can be traced back to the mid-1800s
when Gregor Mendel conducted his plant hybridization experiments,
but information on the inheritance of caladium traits has been rather
scant. To understand the mode of inheritance for three typical leaf
shapes and three main vein colors in caladium, controlled crosses were
made among commercial cultivars and breeding lines, and segregation
of leaf shape and/or main vein color in the progeny was analyzed. The
observed segregation ratios indicated that a single locus with three alleles seemed to determine the main vein color in caladium. The white
vein allele was dominant over the green vein allele, but recessive to
the red vein allele, which was dominant over both white and green
vein alleles. The three leaf shapes (fancy, lance, and strap) in caladium
seemed to be controlled by two co-dominant alleles at one locus. Leaf
shape segregation was skewed in some crosses, which might imply the
existence of other factors involved in caladium leaf shape development.
Chi-square tests revealed that leaf shape and main vein color were
inherited independently in caladium.
(241) Genotyping of Ornamental Flowering Cherry
Germplasm (Prunus species) using SSR Technology
Hongmei Ma, Margaret Pooler*
USDA/ARS U.S. National Arboretum, Floral and Nursery Plants Research Unit, Washington, DC, 20002
Ornamental flowering cherry trees (Prunus species) are popular landscape plants that are used in residential and commercial landscapes
throughout most temperate regions of the world. Most of the flowering
cherry trees planted in the United States represent relatively few species.
The U.S. National Arboretum has an ongoing breeding program aimed
at broadening this base by developing new cultivars of ornamental
cherry with disease and pest resistance, tolerance to environmental
stresses, and superior ornamental characteristics. Knowledge of the
genetic relationships among species would be useful in breeding and
germplasm conservation efforts. However, the taxonomy of flowering
cherry species and cultivars is complicated by differences in ploidy levels
and intercrossing among species. We have used simple sequence repeat
(SSR) markers developed for other Prunus species to screen a diverse
collection of over 200 ornamental cherry genotypes representing 70 taxa
in order to determine the genetic relationships among species, cultivars,
and accessions. Data were generated from 9–12 primer pairs using an
automated DNA genetic analyzer (ABI3770), and subjected to UPGMA
cluster analysis. Extremely high levels of polymorphism were exhibited
among the materials studied, thus indicating that ornamental flowering cherry germplasm has substantial inherent genetic diversity. This
information, combined with traditional morphological characteristics,
will be useful in determining genetic relationships among accessions
in our collection and for predicting crossability of taxa.
(242) ‘Black Pearl’: A New Ornamental Capsicum
John R. Stommel*1, Robert J. Griesbach2
1
USDA, ARS, Vegetable Laboratory, Beltsville, MD, 20705; 2USDA, ARS, National
Arboretum, Floral and Nursery Plant Research Unit, Beltsville, MD, 20705
Considerable diversity exists in Capsicum L. germplasm for fruit and
leaf shape, size and color, as well as plant habit. This morphological
diversity, together with diverse ripe fruit color and varying hues of
green to purple and variegated foliar pigmentation, affords myriad
opportunities to develop unique cultivars for ornamental applications.
The Agricultural Research Service of the United States Department
of Agriculture announces the release of a new pepper [Capsicum annuum (L.)] cultivar named ‘Black Pearl’. ‘Black Pearl’ is intended for
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(240) Mode of Inheritance for Leaf Shape and Main Vein
Color in Caladium
ornamental applications and affords growers a new crop to add to their
bedding and landscape plant assortment. ‘Black Pearl’ combines black
foliage with erect clusters of small round red-pigmented fruit. The
vibrant fruit and foliage colors of this new cultivar add interest to the
summer and fall garden. Black Pearl’ has been trialed extensively for
use as a bedding plant where its compact growth habit, black foliage,
and brightly colored fruit provide an attractive ornamental display.
Limited evaluations suggest that this cultivar is equally well suited for
pot culture under high light conditions. ‘Black Pearl’ was designated
a 2006 All America Selection award winner after completion of national trials in 2004. ‘Black Pearl’ is a release made available from a
cooperative research and development agreement with Pan American
Seed Company. Seed of ‘Black Pearl’ is available from Pan American
Seed Company, 622 Town Road, West Chicago, IL 60185. Plant Variety
Protection for ‘Black Pearl’ is pending.
(243) Ovule and Embryo Culture of ×Chitalpa
tashkentensis Hybrids
Richard T. Olsen*, Thomas G. Ranney, Zenaida Viloria
N.C. State University, Horticultural Science, Mountain Horticultural Crops Research and
Extension Center, Fletcher, NC, 28732-9244
A series of studies were conducted to determine medium components
necessary for ovule and embryo culture of ×Chitalpa tashkentensis Elias
& Wisura hybrids in order to improve recovery of interploid crosses.
Ovules were collected at 2, 3, 4, 5, and 6 weeks after pollination (WAP)
from selfed tetraploid ×Chitalpa (S) and tetraploid ×Chitalpa × diploid
Catalpa bignonioides Walt. (3×) hybrids. Excised ovules were placed
in petri dishes with Schenk and Hildebrandt (SH) medium and 0.7%
agar, with or without coconut-water (2%) and three sucrose concentrations (20, 40, or 80 g·L-1). No ovules germinated for either cross in any
treatment at 2, 3, and 4 WAP. Selfed ovules germinated at 5 WAP, in
both 20 and 40 g·L-1 sucrose. At 6 WAP, 3× ovules germinated in 20
g·L-1 sucrose. Coconut water provided no apparent benefit. Embryos
were apparent at 6 WAP, so a new study was initiated to compare ovule
vs. embryo culture at this sample date. Excised embryos germinated
in greater percentages than ovules, in all treatment combinations at 6
WAP. Germination in 80 g·L-1 sucrose was observed only for S embryos
without coconut water. Greatest 3× germination (16.7%) was observed
for embryos in 20 g·L-1 sucrose without coconut water. A final study
was conducted to investigate the effect of gibberellic acid (GA3) on
embryo germination. Embryos were harvested at 7 WAP for both crosses
and grown in SH medium supplemented with 20 g·L-1 sucrose and 0,
1, 2, or 4 μm GA3. The addition of GA3, regardless of concentration,
increased germination from 30.6% to 99.1% for S embryos and from
11.1% to 99.1% for 3× embryos.
(244) Interspecificic Hybridization of a White-flowered,
Cold-hardy Alstroemeria
Elizabeth L. Kollman*, Mark P. Bridgen
Cornell University, Horticulture, Ithaca, NY 14853.
Alstroemeria, the Inca Lily or Lily-of-the-Incas, is becoming a popular
garden plant in the United States. In past years, the primary interest in
Alstroemeria has been for its cut flowers. However, recent cold-hardy
introductions (USDA hardiness zone 5) have expanded the interest of
this colorful plant as a garden perennial throughout the United States.
Previously, garden interests were restricted to warmer zones in the
southern United States where Alstroemeria could overwinter. This
research describes a breeding procedure that has been used with the
objective to develop a cold-hardy, white-flowered Alstroemeria. The
interspecific hybrids were bred with the use of in ovulo embryo rescue.
Reciprocal crosses were made between several white-flowered cultivars
and the cold-hardy Chilean species Alstroemeria aurea during Summer
2004. Ovaries were collected 10–23 days after hand pollination and
their ovules were aseptically excised. Ovules were placed in vitro on
25% Murashige and Skoog (MS) medium under dark conditions until
germination. Three weeks after germination, they were then placed on
100% MS medium, and subcultured every 3–4 weeks thereafter until they
were large enough for rooting. After rooting and acclimation, plants were
transferred to the greenhouse. Successful hybrids that were produced
1003
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in 2004 were evaluated under greenhouse and field trials during 2005,
and the number of plants with white-colored flowers was noted. Although certain morphological characteristics indicate if plants are coldhardy, the hybrids will be overwintered outside in Ithaca, N.Y. (USDA
zone 5), during the next several years to determine winter hardiness.
velopment. Samples from V49 cracked heavily during 8 weeks in freezer
storage compared to the samples from other fields. A significant interaction
between field and time was also observed in processed samples, indicating that CDF is dependent on both field parameters and freezer storage
time. Significant differences were observed among different fields in
terms of crack morphology, especially after 8 weeks in freezer storage.
Poster Session 8—Postharvest: MCP/Ethylene/Fresh Cut
(31) Quality Changes in Oriental Melon as Affected by
Washing after Fruit Harvest and 1-MCP Treatment
18 July 2005, 1:15–2:00 p.m.
Poster Hall–Ballroom E/F
(29) MCP Treatment Makes Delayed Application of
Ethoxyquin Effective in Control of Superficial Scald of
‘d’Anjou’ Pears
Jinhe Bai*
Oregon State University, Mid-Columbia Agricultural Research and Extension Center,
Hood River, OR, 97031-9512
Superficial scald of ‘d’Anjou’ pears usually develops after storage
of 2 months or longer. MCP application controls scald; however,
fruit lose their ripening capacity if the dosage is >30 ppb, but lower
dosages cannot control scald substantially. In this study, fruit treated
with or without 25 ppb MCP within 2 d after harvest were stored at
–1 °C for up to 5 months. After 1, 7, 30, or 70 d of storage, part of the
fruit were pulled from storage and treated with 1000 ppm ethoxyquin
line spray and immediately returned to the storage, left untreated as
non-ethoxyquin control. Incidence of superficial scald along with the
concentrations of α-farnesene and conjugated trienes (CTs), and the
ripening capacity of fruit were investigated after 3, 4, and 5 months
storage. All fruit ripened properly within 7 d of conditioning at room
temperature regardless of treatments. Both of MCP or ethoxyquin-1d
(ethoxyquin was applied after 1 day storage at –1 °C) alone controlled
scald for only 3 months; however, MCP + ethoxyquin controlled scald
for 5 months, whenever ethoxyquin was applied between 1 to 70 d
after storage. Thus, with 25 ppb MCP treatment, which is simple,
with rapid and mass treatment available, a delayed application (up to
70 d) of ethoxyquin becomes effective to control scald. Furthermore,
the later application of ethoxyquin within 70 d after MCP treatment,
the less incidence of scald was observed. Scald is caused by the CTs
oxidation products of α-farnesene. MCP and ethoxyquin inhibited accumulation of CTs of fruit peel by different mechanisms. MCP inhibited
the production by influencing ethylene production through control of
α-farnesene synthesis; however, ethoxyquin worked by inhibiting the
oxidation of α-farnesene to the CTs.
(30) Edaphic Factors on Crack Development of Cut and
Peel Carrots
Phillip Joy*1, Rajasekaran Lada1, Cameron Fullerton2,
Brian Williams2, Angus Ells3
1
Nova Scotia Agricultural College, Plant and Animal Sciences, Truro, Nova Scotia, B2N
5E3, Canada; 2Oxford Frozen Foods Ltd., Hillaton Foods; 3Oxford Frozen Foods Ltd,
Bragg Lumber
The quick-frozen (QF) cut and peel processing industry is growing and
has significant economical importance. Crack development formation
(CDF) and enhancement is a major obstacle in QF carrot processing
since it lowers product quality, profitability and consumer preference.
Studies were initiated to determine the role of edaphic factors on crack
development. Carrot samples (var. Sugarsnax) were collected from nine
different fields before processing, after processing, and after 8 weeks
of -8 °C freezer storage. Samples were tested for the percent cracked;
the length, width, and depth of cracks; and membrane stability using
electrical conductivity per gram (EC/g). Membrane injury index (MII)
was also analyzed on freezer-stored samples. Very few cracks and low
EC readings were observed in treatments prior to processing, with the
exception of field VC38. Samples taken at the end of the processing line
had a higher percentage of visual cracks and significant differences were
found between fields in EC/g and length, but not in width or depth of
cracks. Freezer-stored samples had significant differences in all parameters, including EC/g, MII, crack length, width, and depth, indicating that
the length of freezer storage time can increase the potential for crack de-
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final6_20July HS.indb 1004
Yu-Jin Park*, Duk-Hee Cha, Ki-yun Jung, Bong-Hwa Kang,
Jung-Myung Lee
KyungHee Univ., Horticulture, KiHeung-up, YongIn-Si, Gyeonggi-Do, 449701, Korea
Washing oriental melon (Cucumis melo var. makuwa Makino) is a standard procedure because it facilitates the precise elimination of defective
fruit, such as fruit having internal decay symptoms, and also facilitates
easier handling of fruit by the elimination of gummy substances on the
fruit surface. In most fresh fruits and vegetables, however, washing has
never been recommended unless it is related to other practices, such
as waxing or immediate processing. Harvested oriental melons were
placed in a big water tank and washed with a brush machine immediately
before grading, using an automatic grader. Fruit that had sunk down
to the bottom of the tank were discarded, as they were premature-fermented fruit with no commercial value. Fruit, intact or washed, were
treated with 1-MCP at 0.5–2.0 ppm for 12 hours and stored at room
temperature for 3 weeks. Flesh firmness, soluble solids contents, fruit
petiole color, and changes of surface suture color were measured to
evaluate storability of the fruit. The washed fruit exhibited poor skin
color and early suture-browning as compared to the non-washed fruit,
regardless of 1-MCP pretreatment. 1-MCP treatment was also effective
in maintaining fresh fruit quality as compared to the non-treated fruit.
1-MCP effects were, however, more pronounced in relatively smaller
and less mature fruit as compared to the fully mature fruit. 1-MCP was
also effective in maintaining white suture color, the most important
visual factor currently used for quality evaluation in oriental melon.
(32) Effects of 1-MCP Treatments on Several Major Apple
Cultivars Grown in Korea
Seok-Kyu Jung*, Jung-Myung Lee
Kyunghee University, Horticulture, Seocheon-ri Giheung-eup, Yongin-si, Gyeonggi-do,
449-701, Korea
Fruits of ‘Tsugaru’ (an early maturing cultivar), ‘Hongro’ (mid-season
cultivar), and ‘Fuji’ (late cultivar), were harvested at different times
of the year, depending upon their maturity, and treated with 1-MCP
at 0.0, 0.5, 1.0, and 2.0 ppm for 8-24 hours. Fruits were also treated
with 1-MCP at different times after harvest. Portions of 1-MCP-treated
apples were also treated with ethylene in order to study the interaction
between 1-MCP and ethylene. In other experiments, fruits were treated
with ethylene first and then treated again with 1-MCP. Major results
are as follows. Treatment of 1-MCP greatly retarded the senescence
of ‘Tsugaru’ apple stored at room temperatures as compared with the
control. The sooner the time of 1-MCP treatment after harvest of fruit,
the greater was the 1-MCP effect. In contrast to the time of 1-MCP treatment, the concentration of 1-MCP and duration of 1-MCP infiltration
in a closed chamber exhibited only a minor effect. Ethylene treatment
immediately before and/or after the 1-MCP treatment showed only the
1-MCP effect, thus clearly showing that 1-MCP treatment could completely reverse or counter the ethylene effect in ‘Fuji’ apples. Repeated
treatments of 1-MCP after a certain period of low temperature storage
of ‘Fuji’ apples were more effective than a single treatment. Parameters
related with fruit quality will be discussed in detail.
(33) Effect of Natural Products on Decay and Antioxidant
Activities of Fresh-cut Papayas
Chien Wang*1, Korakot Chanjirakul2, Shiow Wang3,
Jingtair Siriphanich2
1
U.S. Department of Agriculture, Produce Quality and Safety Laboratory, BARCW, Beltsville, MD, 20705; 2Kasetsart University, Department of Horticulture;
3
U.S. Department of Agriculture, Fruit Laboratory
The effect of naturally occurring volatile compounds on decay and
HORTSCIENCE, VOL. 40(4), JULY 2005
6/20/05 5:00:53 PM
(34) Maintaining the Analytical and Microbial Quality of
Fresh-cut Apple Slices using Hot Water Pretreatment and
a Low pH Dip Treatment
Robert Saftner*, Judith Abbott, Arvind Bhagwat
USDA Agricultural Research Service, Produce Quality and Safety Laboratory, Beltsville,
MD, 20705
A calcium ascorbate processing formulation is commercially used to
prevent browning on fresh-cut apple slices but has little to no antimicrobial activity. Intact apples were surface-sanitized with chlorine water at
20 °C or water at 60 °C, processed into fresh-cut slices, and the slices
dipped in a calcium ascorbate formulation or a solution of isoascorbic
acid, calcium, and N-acetylcysteine at pH 2.0. The commercial and
experimental dip treatments similarly maintained cut surface color,
Kramer firmness, and aromatic volatile concentrations during 3 weeks
of storage at 5 °C in air. Freshly prepared experimental dip treatment
reduced the native bacterial population of the apple slices prepared
from sanitized apples better than the calcium ascorbate treatment.
With repeated use, the experimental dip solution became adulterated
with apple tissue and juice and rapidly lost its antibacterial activity.
Concomitantly the pH of the dip solution increased to 2.6 or higher.
The lost antibacterial activity could be restored in highly contaminated
experimental dip solutions by back titrating to pH 2.0. The experimental dip treatment also reduced the overall yeast and mold population,
but specifically enhanced growth of Penicillium expansum on slices
prepared from chlorine-sanitized apples. A hot water pretreatment of
intact apples at 60 °C for 3 min prior to fresh-cut processing essentially
eliminated P. expansum contamination on the slices. The results indicate
that the experimental dip treatment is a promising alternative to calcium
ascorbate treatment for analytical and microbial quality retention of
fresh-cut apple slices during storage, especially when the apple slices
are processed from hot water-treated apples.
(35) The Influence of 1-MCP on Firmness, Soluble Sugar
Levels, Chlorogenic Acid, and Total Phenolic Compounds
in Ripening Banana Fruit
Daniel A. Stanley*, Donald J. Huber
University of Florida, Horticultural Sciences, Gainesville, FL, 32611-0690
In previous studies, 1-methylcyclopropene (1-MCP) was shown to
significantly suppress peel degreening and appearance of senescent
spotting of banana fruit (Stanley and Huber, 2004). In the present study,
the effect of the ethylene antagonist on banana pulp soluble sugar levels
and on peel soluble and total phenolics was measured. One hundred
and sixty hands (10 boxes) of banana fruit (Musa acuminata cv. Cavendish) were treated with ethylene (300 μL·L-1, 24 h, 15 °C, 90% RH)
at a commercial ripening facility in Bradenton, Fla., and transported
by truck (15 °C) to the University of Florida. Fruit were sorted and
placed in 174-L ripening chambers, where 80 hands received 500
nL·L-1 1-MCP for two 12-h periods at 18 °C, while the other 80 hands
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final6_20July HS.indb 1005
(controls) were maintained in identical containers without 1-MCP for
equal time periods at 18 °C. Mean whole fruit firmness in both treatment
groups was 140 N and decreased to 15 N (controls) and 30 N (1-MCP)
by day 12. Soluble sugars in the pulp of control fruit achieved levels
between 160–180 mg·g-1 fresh weight by day 8, while 1-MCP treated
fruit required about 12 days to achieve similar soluble sugar levels.
Total phenolic compounds present in peel tissue of control and 1-MCP
treated fruit required 10 and 14 days, respectively, to achieve levels
of about 4000 μg·g-1 fresh weight. Chlorogenic acid levels, a subset
of total peel phenolic compounds, peaked above 500 μg·g-1 by day 10
in control fruit and by day 12 in 1-MCP treated fruit. Maintenance of
fruit firmness along with the achievement of acceptable sugar levels
of 1-MCP treated fruit demonstrate possible benefits of suppression of
ethylene action for retail and processing markets for banana fruit.
POSTERS–MONDAY
antioxidant activities in fresh-cut papayas (Carica papaya L.) was
studied. Exposure to methyl jasmonate (MJ), methyl salicylate (MS) or
allyl isothiocyanate (AITC) substantially delayed the onset and reduced
the severity of decay during and after storage at 5 °C. Treatment with
tea tree oil (TTO) or ethanol (ETOH) was also effective in retarding
decay, but to a lesser extent. No beneficial effect was obtained with the
use of vinegar vapor. MJ and MS increased oxygen radical absorbance
capacity and elevated the activities of several antioxidant enzymes,
including glutathione reductase, glutathione peroxidase, guaiacol
peroxidase, ascorbate peroxidase, monodehydroascorbate reductase,
dehydroascorbate reductase, and superoxide dismutase. The nonenzyme
components in the ascorbate-glutathione cycle were also increased
by MJ and MS treatments, including ascorbate and glutathione. It is
possible that MJ and MS treatments enhanced the antioxidant system
and increased the resistance of tissue to decay. However, while AITC
also suppressed the development of decay in papaya slices, it had little
effect on antioxidant levels and antioxidant enzyme activities. Apparently, AITC exerted its effect through different mechanisms. Studies
are in progress to determine if AITC inhibits decay directly via its
antimicrobial properties.
(36) The Influence of 1-Methylcyclopropene (1-MCP) on
‘Athena’ Cantaloupe Fruit Harvested at the Pre-ripe,
Half-slip, and Full-slip Development Stages
Jiwon Jeong*, Donald Huber
1
Institute of Food and Agricultural Sciences, Horticultural Sciences Department, University
of Florida, Gainesville, FL, 32611
The present study was performed to characterize the physiological
responses of cantaloupe [Cucumis melo (L.) var. reticulates ‘Athena’]
fruit harvested at preripe (1/4 slip), half-slip, and full-slip stages of
development and treated with 1-methylcyclopropene (1-MCP) prior
to storage at 13 or 15 °C. Cantaloupe fruit (1/4 to full-slip stage) were
treated with 1-MCP (0.01 and 1 μL·L-1) for 18 hours at 20 °C and
then stored at 15 °C (pre-ripe fruit) or 13 °C (half- and full-slip fruit).
The firmness of pre-ripe ‘Athena’ fruit was significantly retained in
response to 1 μL·L-1 1-MCP, but did not differ greatly from control
fruit in response to 0.01 μL·L-1 1-MCP. Control fruit reached an edible
condition (≈70 N) after 6 days of storage at 15 °C and persisted until
day 12 (50 N), whereas 1 μL·L-1 1-MCP-treated fruit reached an edible
stage after 17 days and persisted through 21 days (over 60 N). Fruit
treated with 1-MCP exhibited slightly (0.01 μL·L-1) or dramatically (1
μL·L-1) lower electrolyte leakage throughout storage. 1-MCP (1 μL·L-1)
significantly suppressed ethylene production and respiratory rates of
pre-ripe cantaloupe during storage at 15 °C. Firmness retention was
also highly significant for cantaloupe harvested and treated with 1-MCP
(1 μL·L-1) at the half-slip and full-slip stages of development. 1-MCP
treatment had a significant effect at reducing decay incidence and the
occurrence of depressed or sunken regions of the fruit surface.
(37) Metabolism of Apple Peel Constituents during
Ripening is Differently Regulated by Ethylene
James Mattheis*, David Rudell
1
USDA, ARS, TFRL, Wenatchee, WA, 98801
Metabolism of peel constituents was assessed during ripening of ‘Delicious’ and ‘Golden Delicious’ apples. The ethylene action inhibitor
1-methylcyclopropene (1-MCP) and/or controlled atmosphere storage
(CA) were used to limit ethylene activity during and after storage at
1 °C. ‘Delicious’ apples not exposed to 1-MCP developed a brownish discoloration (not superficial scald) during the initial 2 months of
storage in air. LC/MS analyses of peel components indicated 1-MCP
and/or CA inhibited the degradation of compounds responsible for red
peel color (i.e., idaein) as well as other flavonoids. Ethylene regulation
of metabolism of other phenolic and related constituents including
(-)epicatechin and chlorogenic acid appears to be compound specific.
The (-)epicatechin content is not impacted by 1-MCP or CA, while
chlorogenic acid accumulation is reduced in fruit exposed to 1-MCP
and/or stored in CA. β-carotene and lutein content in peel of ‘Delicious’ fruit stored in air was lower compared with untreated controls.
Chlorophyll degradation was enhanced in air-stored fruit previously
exposed to 1-MCP; however, this result was not observed in 1-MCP
exposed fruit from CA. Results for ‘Golden Delicious’ apples also
indicated that exposure to 1-MCP and CA, as well as storage duration,
impacts metabolism of peel constituents. Chlorophyll degradation was
delayed in fruit previously exposed to 1-MCP and then stored in CA.
Impacts of 1-MCP and storage environment on concentrations of other
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6/20/05 5:00:54 PM
‘Golden Delicious’ peel constituents increased with storage duration.
The results indicate metabolism of apple fruit peel constituents during
fruit ripening is differentially regulated by ethylene.
Poster Session 9—Sustainable/Organic and Water
Utilization in Horticulture
18 July 2005, 1:15–2:00 p.m.
Poster Hall–Ballroom E/F
(160) Are All Vermicomposts Created Equal?
Gray R. Bachman*
Illinois State University, Department of Agriculture, Normal, IL, 61790-5020
The horticulture industry continues to show interest in using stabilized
organic wastes as a component of container media. Vermicompost,
also known as worm-worked waste or worm castings, is one of these
materials of interest and can be produced from a number of organic
wastes, including manure wastes. One issue that has not been addressed
is the uniformity of vermicomposts produced from wastes of different
sources. Are all vermicomposts created equal? The uniformity of vermicompost is important for growers to consider when using as a medium
amendment. This research project investigated the physical properties of
vermicompost 1) from different sources of wastes and 2) from a single
waste source sequentially sampled over time. The first stage determined
the physical properties of vermicompost from beef manure, hog manure, and peat-based media used by two earthworm growers. There
were significant differences between the four vermicomposts in bulk
density, air volume, percent air volume, percent volumetric moisture,
total porosity, and water holding capacity. The second stage involved
determining the physical characteristics of vermicompost produced
from beef manure collected at the Illinois State University Research
Farm from cattle receiving a consistent diet through the year. Manure
was collected bimonthly. There was no difference in vermicompost
bulk density among the samples. There were significant differences
in air volume, percent air volume, percent volumetric moisture, total
porosity, and water holding capacity. These changes in vermicompost
physical characteristics must be quantified for growers to accurately
predict performance as a growth medium amendment.
(161) Use of Food Waste Composts in Ornamental Plant
Production in Florida
Olivia Riffo, Monica Ozores-Hampton*
1
Universidad de las Americas, Horticulture, Santiago, Chile; 2University of Florida/SWFREC, Horticulture, Immokalee, FL, 34143-9515
The nursery industry in Florida relies entirely on peat as a major component in potting soil. Escalating peat costs are a major concern, so
alternative media are attractive in Florida. The objectives of the project
were to study the feasibility of using food waste compost (FWC) to
replace peat in different annual ornamental crops. The experiments
were conducted in Spring 2004 at the University of Florida/SWFREC
Immokalee, Fla. The crops basil (Ocimum basilicum L.), marigold
(Calendula officinalis L.), and periwinkle (Vinca rosea L.) were grown
in mixes of FWC. The treatments were: 1) 100% FWC; 2) 60% FWC,
25% vermiculite, 15% perlite; 3) 30% FWC, 30% peat, 25% vermiculite,
15% perlite; and 4) 0% FWC, 60% peat, 25% vermiculite, 15% perlite,
by volume. Basil ‘U.H’ was direct seeded; marigold and periwinkle
were transplanted (5 cm tall) in pots (2 inches). All treatments received
4 g per pot of Osmocote (19-6-12) for 4 months. Percentage of basil
germination and biomass were higher in mixes with 60% and 30%
FWC as compared with 100% FWC and the control. Lower basil biomass in the control media was due to high weed biomass grown in the
peat control media. There were no differences in biomass and number
of flowers per plant among marigold treatments. But, periwinkle dry
biomass and number of flowers per plant were higher in the control and
30% FWC than in 60% and 100% FWC, indicating a negative effect
of FWC in periwinkle. It can be concluded that FWC may become a
viable alternative to replace peat in basil and marigold when included
in potting mixes between 30% and 60% by volume, but a negative
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final6_20July HS.indb 1006
effect was reported in periwinkle production.
(162) Edible Fungal Growth and Fruiting on Composted
Containerized Inedible Crop Biomass
Leopold M. Nyochembeng*, Caula A. Beyl, Rodulfo P. Pacumbaba
Alabama A&M University, Department of Plant and Soil Science, Normal, AL, 35762
Current goals for space exploration are predicated upon long-term
manned space flights and colonization of planetary habitats. Long periods
in space without payloads of necessary items from Earth require the
development of a self-sustaining ecosystem that will allow astronauts to
grow their own food and efficiently recycle the waste products. Crops
suggested for growth in space include wheat, rice, carrots, soybean,
mushrooms, etc. Optimal and rapid biodegradation of lignin and other
cellulosic material of crop residues by candidate edible white rot fungal
strains is paramount in the use of these organisms to achieve effective
biomass recycling in an advanced life support system (ALS). The incorporation of organic N into the substrate and pairing crop residues may
enhance growth and fruiting of the edible fungi, thus increasing the rate
of biodegradation of the substrates and biomass recycling. We investigated the mycelial growth of two strains of Pleurotus ostreatus (‘Grey
Dover’ and ‘Blue Dolphin’) on processed single vegetative residues of
soybean, cowpea, tomato, sweetpotato, or their 1:1 combination with
wheat or rice straw. Growth and fruiting of the two strains including
another strain (‘Pohu’) on rice straw mixed with solid thermophilic
aerobic reactor (STAR) effluent for degradation and recycling were
also studied. Mycelial growth and fruiting in ‘Grey Dover’ and ‘Blue
Dolphin’ were significantly repressed on sweetpotato and basil; however,
growth of the two strains was improved when sweetpotato and basil
substrates were paired with rice or wheat straw. Fruiting was prolific
in paired combinations of soybean with wheat or rice straw. High
concentration of STAR residue enhanced mycelial growth; however,
a relatively lower concentration was required for abundant fruiting.
(163) Influence of Single or Mixed Cover Crops on
Biomass Production and Fruit Yields of Eggplant Grown
with or without Synthetic Nitrogen
Wayne F. Whitehead*, Bharat P. Singh
1
Fort Valley State University, Agricultural Research Station, Fort Valley, GA, 31030-4313
The purpose of this study was to evaluate how leguminous and nonleguminous cover crops alone or in mixture with synthetic nitrogen rates
affect aboveground biomass, fruit number, and yield of eggplant. The
following fall–spring fertility treatments were applied using randomized complete-block design with three replications: 1) fall-0 N, fallow;
spring-0 N; 2) fall-0 N, abruzzi rye; spring-0 N; 3) fall-0 N, hairy vetch;
spring-0 N; 4) fall-0 N, abruzzi rye+hairy vetch; spring-0 N; 5) fall-0 N,
fallow; spring-70 kg·ha–1 N; 6) fall-0 N, abruzzi rye; spring-70 kg·ha–1
N; 7) fall-0 N, hairy vetch; spring-70 kg·ha–1 N; 8) fall-0 N, abruzzi
rye+hairy vetch; spring-70 kg·ha–1 Na; 9) fall-0 N, fallow; spring-140
kg·ha–1 N, 10) fall-0 N, abruzzi rye; spring-140 kg·ha–1 N; 11) fall-0 N,
hairy vetch; spring-140 kg·ha–1 N; and 12) fall-0 N, abruzzi rye+hairy
vetch; spring-140 kg·ha–1 N. In Spring 2004, ‘Megal’ eggplant seedlings were transplanted. Total yield and fruit number were compiled
over 7 weeks, while total vegetative dry matter was measured at final
harvest. Maximum aboveground biomass (227.6 g/plant), total yield
(28.7 Mg·ha–1) and fruit number (13/plant) were produced by fall-0
N, hairy vetch; spring-70 kg·ha–1 N. Minimum aboveground biomass
(53.0 g/plant) was produced by fall-0 N, abruzzi rye; spring-0 N, while
minimum total yield (7.8 Mg·ha–1) and fruit number (5/plant) were
produced by fall-0 N, fallow; spring-0 N. Results imply that hairy vetch
supplemented with N at 70 kg·ha–1 is most effective in supporting fruit
number and yield of eggplant.
(164) Effect of a Non-leguminous Cover Crop, Tillage
Practices, and Inorganic Nitrogen on Aboveground
Biomass Production and Yields of Southernpea
Wayne F. Whitehead*, Bharat P. Singh
1
Fort Valley State University, Agricultural Research Station, Fort Valley, GA, 31030-4313
The objective of this study was to examine how a non-leguminous
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(165) Use of Chicken Manure as Source of Nutrients for
Sweet Corn Production
1
1
2
Muddappa Rangappa* , Harbans Bhardwaj , Harry Dalton
1
2
Virginia State University, Agricultural Research, Petersburg, VA, 23806; VA Dept. of
Cons. & Rec., Water Conservation & Recreation, Richmond, VA, 23219
An on-farm animal manure, such as chicken manure, can be a source of
nutrients for the growth and production of agricultural crops. However,
use of manures at rates that are considered adequate for crop production
may cause excessive accumulation of phosphorus (P) and also result in
leaching of nitrogen (N), thus leading to potential pollution of ground
and surface water. Composting of manures with a carbon (C) source
can reduce P and N to manageable levels to support production of
crops. In order to determine the potential of composted manure for crop
production, we studied growth and production of sweet corn by using
poultry manure composted with a carbon source of crimson clover hay
or wheat straw. These experiments, conducted during 2002 and 2003,
compared six treatments: 1) uncomposted chicken manure alone; 2)
composted with wheat straw turned weekly; 3) composted with wheat
straw turned bi-weekly; 4) composted with crimson clover hay turned
weekly; 5) composted with crimson clover hay turned bi-weekly; and
6) a control with a commercial recommendation rate of N fertilizer.
These treatments resulted in 9244; 13,866; 15,688; 16,734; and 11,977
marketable ears/acre, respectively, indicating significant superiority of
treatments 4 and 5 over all others. Similar results were obtained for
ear length, ear fresh weight, and plant height. Results indicated that
composting of poultry litter with wheat straw or crimson clover hay
is a viable way to utilize poultry manure for production of sweet corn
and other agricultural crops. This study implies that composting of
on-farm animal manure with organic material, such as hay and straw,
could play an important role in development of an environmentally
friendly, economically feasible, and sustainable organic production
of agricultural crops.
(166) Economic Return in Production of Lettuce and
Cantaloupe Is Affected by Cropping System and Value of
Hand Weeding
Edmund J. Ogbuchiekwe1, Mathieu Ngouajio2,
Milton E. McGiffen*1
1
University of California, Botany and Plant Sciences, Riverside, CA, 92521; 2Michigan
State University, Horticulture, East Lansing, MI, 48824
Field experiments were established at the University of California
Desert Station in Coachella Valley from 1998 to 2000. The main
plot treatments included: 1) summer cowpea used as mulch in the
fall; 2) summer cowpea incorporated into soil in the fall; 3) summer
sudangrass incorporated into the soil in the fall; and 4) summer fallow (bare-ground). An economic comparison of cover crop treatments
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and crop management programs vs. the effect on yield, crop value,
value of hand weeding, costs of production and net return, and dollar
investment from each treatment was determined. Among the cropping systems tested in 1999, lettuce following the incorporation of
a cowpea cover crop produced the highest yield (1082.43 boxes/ha),
with a net return of $883.04/ha. The return for each dollar invested in
the cowpea-incorporated system was an additional $0.65 if cowpeaincorporated was chosen over cowpea mulch. In 2000, the net return
from lettuce following cowpea-incorporated was much higher with
1294.23 boxes/ha and a net return of $1698.46/ha. In 1999, cantaloupe
grown in the cowpea-incorporated system had the highest net return
of $973.34/ha, with 874.58 boxes. An additional $0.93 was made for
choosing cowpea-incorporated over sudangrass. In 2000, cantaloupe
grown in the cowpea-incorporated system had even higher yields than
in 1999, producing 1522.89 boxes/ha and returning over $3000.00.
And an additional $0.93 was made for choosing cowpea-incorporated
over sudangrass cover crop. Overall, the rate of return on investment
favored cowpea-incorporated over all cover crops.
POSTERS–MONDAY
cover crop, three tillage practices, and two synthetic nitrogen rates
influence aboveground biomass, and yields of southernpea. The following fall–spring fertility treatments were applied using randomized
complete-block design with four replications: 1) fall-0 N+abruzzi rye;
spring-conventional till+0 N; 2) fall-0 N+abruzzi rye; spring-strip till+0
N; 3) fall-0 N+abruzzi rye; spring-No till+0 N; 4) fall-0 N+abruzzi rye;
spring-conventional till+30 kg·ha–1 N; 5) fall-0 N+abruzzi rye; springstrip till+30 kg·ha–1 N; 6) fall-0 N+ abruzzi rye; spring-No till+30 kg·ha–1
N. In Spring 2004, ‘Mississippi Purple’ southernpea was drill planted
in all plots. Pod yields were harvested at the fresh-market mature green
stage and dry pod stage, while total vegetative dry matter was collected
at the mature green stage. Optimal aboveground biomass (32.7 g/plant)
was produced by fall-0 N+abruzzi rye; spring-strip till+30 kg·ha–1 N
treatment, while maximum fresh-market pod yield (4.9 Mg·ha–1) and
dry pod yield (2.2 Mg·ha–1) were produced by fall-0 N+abruzzi rye;
spring-strip till+0 N. Minimum aboveground biomass (15.6 g/plant),
fresh-market pod yield (2.6 Mg·ha–1) and dry pod yield (0.9 Mg·ha–1)
were produced by fall-0 N+ abruzzi rye; spring-conventional till+0 N
treatment. Spring-strip till at 0 N produced fresh-market pod yield, dry
pod yield, and plant biomass similar to spring-strip till at 30 kg·ha–1 N.
Results suggest strip-till provided adequate tilth and nitrogen fertilizer
was not needed for producing southernpea in middle Georgia.
(167) The Effect of Cover Crops and Alternative
Management Practices for the Management of Soil-borne
Diseases in Sweet Onions
Hector Valenzuela*, Robin Shimabuku, John Cho
University of Hawaii at Manoa, CTAHR, Honolulu, HI, 96822
Pink root (Phoma terrestris) is among the major limiting factors for the
production of sweet onions on Maui, Hawaii. Few management options
exist for the control of pink root in onions. Two split-plot experiments
were conducted in the area of Kula, Maui, over 2 years to evaluate
several alternative management practices. In Expt. 1, the main plots
were a rotation with cabbage, solarization with a clear plastic mulch,
and a fallow period. Subplots were plus or minus Vapam fumigation.
Sub-subplots were biomass application of Sudex or rape, inoculation with
an EM biostimulant, and control. Each treatment had four replications
for a total of 96 plots. In the follow-up experiment, the main plots were
Vapam fumigation, rotation with either a Sudex or rape cover crop, and
controls. The subplots were plus or minus EM biostimulant application.
In Expt. 1, three separate treatments: solarization, cabbage rotation, and
Sudex incorporation had a synergistic effect with Vapam fumigation.
Fumigation and solarization also decreased pink root incidence. Rape
contributed to a decreased disease incidence while EM contributed to
increased bulb size. In Expt. 2, EM and rape contributed to increased
yields. Rape and sorghum rotations contributed to decreased pink root
incidence. EM inoculation had differential effects on several diseases,
contributing to reduced bacterial bulb rot levels. The data indicate
that growers may have several alternative management tools at their
disposal, in addition to proper varietal selection, to improve yields and
reduce disease incidence in sweet onions.
Poster Session 10—Fruit and Nut Breeding
18 July 2005, 1:15–2:00 p.m.
Poster Hall—Ballroom E/F
(228) ‘Golden Hills’ Pistachio—A Replacement for
‘Kerman’
Dan E. Parfitt1, Craig E. Kallsen*2, Joe Maranto2
1
Univ. of California, Davis, Dept. of Plant Sciences, Davis, CA, 95616; 2Univ. of California,
Kern Co. Farm Advisors Office, Bakersfield, CA, 93307
‘Golden Hills’ is a new female pistachio cultivar with improved
performance characteristics compared to the standard female cultivar
Kerman. ‘Golden Hills’ produces a greater yield and higher percentage of split, edible nuts than ‘Kerman’ while maintaining a similar
low percentage of loose shells and kernels. Harvest date is 2–4 weeks
earlier than ‘Kerman’, which will permit growers to extend their harvest
period and better utilize their harvesting equipment and personnel.
Earlier harvest may reduce disease in the northern production areas
of California by permitting an earlier harvest before fall rains, as well
as reducing navel orangeworm infestations. The cultivar requires less
chilling than ‘Kerman’, which improves uniformity of foliation, bloom,
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nut set, nut fill, and uniformity of nut maturity at harvest in years with
insufficient chilling for ‘Kerman’. Based on all of our evaluations, this
cultivar appears to be an exceptional producer and has the potential to
increase grower profits by more than 40%.
(229) ‘Lost Hills’ Pistachio—A New and Improved
Cultivar
Dan E. Parfitt*1, Craig E. Kallsen2, Joe Maranto2
1
Univ. of California, Davis, Dept. of Plant Sciences, Davis, CA, 95616; 2Univ. of California,
Kern Co. Farm Advisors Office, Bakersfield, CA, 93307
‘Lost Hills’ is a new female pistachio cultivar that is being released
as a potential replacement for ‘Kerman’, the industry standard female
cultivar. ‘Lost Hills’ produced substantially higher percentages of split,
edible nuts than ‘Kerman’ in 2003 when split percentages for ‘Kerman’
were very poor due to reduced winter chilling, a condition that is likely
to be more frequent in the future. Nut size for ‘Lost Hills’ is larger than
for ‘Kerman’. Harvest date is 2–4 weeks earlier than ‘Kerman’, which
will permit growers to extend their harvest period and better utilize
their harvesting equipment and personnel. Earlier harvest may reduce
disease in the northern production areas of California by permitting an
earlier harvest before fall rains, as well as reducing navel orangeworm
infestations. The cultivar requires less chilling than ‘Kerman’, which
improves uniformity of foliation, bloom, nut set, nut fill, and uniformity
of nut maturity at harvest in years with insufficient chilling for ‘Kerman’. This cultivar could increase grower profits by more than 20%
above that received for ‘Kerman’.
(230) Genetic Differences in Sweet Cherry Fruit Size Are
Determined by Cell Number and Not Cell Size
James W. Olmstead*1, Amy F. Iezzoni1, Matthew D. Whiting2
1
Michigan State University, Department of Horticulture, East Lansing, MI, 48824;
Washington State University, Irrigated Agriculture Research and Extension Center,
Prosser, WA, 99350
2
Although maximizing fruit size is critical for profitable sweet cherry
(Prunus avium L.) production, little is known about the cellular differences among and between cultivars that contribute to fruit size differences. A wide range of fruit size exists among sweet cherries, and, due
to cultural and environmental differences, significant variation exists
among genetically identical fruit from the same cultivar. To determine
the relative contributions of flesh cell number and cell size to final fruit
size in sweet cherry, equatorial sections of three cultivars with a wide
range in final average fruit size [‘New York 54’ (NY54; 1.4 g fresh
weight, 11.8 mm diameter), ‘Emperor Francis’ (EF; 6.1 g, 21.0 mm),
and ‘Selah’ (12.8 g, 25.5 mm)] were created from mature fruit. Cells
intersecting a transverse line were counted and average cell length
was calculated. The average cell numbers were significantly different
(P ≤ 0.05) between ‘NY54’, ‘EF’, and ‘Selah’ (26.7, 47.4, and 83.2,
respectively), indicating that flesh cell number is the major contributor to differences in fruit size between cultivars. Flesh cell numbers of
‘NY54’, ‘EF’, and ‘Selah’ were similar at bloom and increased rapidly
for a short duration after fertilization, suggesting a key developmental
period for fruit size differences. To determine the contribution of cell
number differences to variation in fruit size within a cultivar, fruit from
‘Bing’ and ‘Regina’ trees exhibiting a range of size due to cultural and
environmental differences were measured. In both cases, average cell
number was not significantly different (P = 0.9, P = 0.3, respectively),
while average cell size was (P ≤ 0.05), further indicating fruit flesh cell
number is a genetically controlled trait.
(231) Correlation of Cluster Number and Tendril Density
in Grapevines
Peter Cousins*
1
USDA-ARS, Plant Genetic Resources Unit, New York State Agricultural Experiment
Station, Cornell University, Geneva, NY, 14456
The grapevine shoot has a zone in which leaf-opposed clusters are found
at the nodes. Beyond the cluster zone, leaf-opposed tendrils are borne at
the nodes in a patterned distribution. Cluster number is a primary yield
component and selection programs for increasing yield in grapevine
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frequently consider cluster number. However, selection for increased
cluster number requires direct observation, which is only possible once
the vine matures. Clusters and tendrils are developmentally related, so it
may be that tendril density (tendrils per node) reflects cluster number. In
contrast to cluster number, tendril density can be observed on plants of
all ages. The hypothesis that tendril density is related to cluster number
was tested here. Cluster numbers and tendril density were assessed
on 10 primary shoots each of 180 grapevine (Vitis) accessions. The
accessions analyzed are cultivars and wild species collections held in
the United States National Plant Germplasm System. The correlation
coefficient of the number of clusters and tendril density was calculated
using the means of 10 observations per accession. Tendril density was
determined by calculating the mean number of tendrils per node in
the nodes beyond the cluster zone. Cluster number and tendril density
were positively correlated; the correlation coefficient was 0.35. This
implies that vines with more tendrils per node also tend to have more
clusters. The positive correlation of cluster number and tendril density
has implications for grapevine improvement, pointing to the possibility
of indirect selection for higher cluster number through selection for
higher tendril density. Correlation between juvenile tendril density and
mature cluster number is yet to be tested.
(232) ‘Randy’ Pistachio—A New Early Flowering Male
Cultivar
Dan E. Parfitt1, Craig E. Kallsen*2, Joe Maranto2
1
Univ. of California, Davis, Dept. of Plant Sciences, Davis, CA, 95616; 2Univ. of California,
Kern Co. Farm Advisors Office, Bakersfield, CA, 93307
‘Randy’ is an early flowering male pistachio that will be used as a
pollenizer for ‘West Hills’ and ‘Lost Hills’. It has excellent flowering
synchrony with ‘West Hills’ and ‘Lost Hills’ and can be used to cover
the earlier part of the ‘Kerman’ flowering period during seasons in which
‘Kerman’ flowering is extended. This generally occurs during seasons
of low chill, which are expected to become more frequent in the future
due to continued global warming. ‘Peters’, the standard male used to
pollenize ‘Kerman’, often flowers too late to cover the earlier part of
the ‘Kerman’ bloom period under these conditions or to serve as an
effective pollenizer for the new female cultivars. ‘Randy’ was selected
for high pollen viability, pollen durability, and a high level of pollen
production (based on visual evaluation). ‘Randy’ flowers 1–3 weeks
earlier than ‘Peters’, the standard pollenizer for ‘Kerman’.
(233) Relationship of European Persimmon Cultivars to
Asian Cultivars Is Characterized using AFLPs
Keizo Yonemori1, Chitose Honshu2, Malli Aradhya3,
Edgardo Giordani4, Elvio Bellini4, Dan E. Parfitt*5
1
Kyoto University, Graduate School of Agriculture, Sakyo-ku, 606-8502, Kyoto, 6068502, Japan; 2University of Miyazaki, Facuty of Agriculture, Miyazaki, 889-2192, Japan;
USDA-ARS, National Clonal Germplasm Repository, Univ. of California, Davis, CA,
95616; 4University of Florence, Department of Horticulture, Polo Scientifico, Viale delle
Idee, 30, 50019, Sesto Fiorentino (FI), 30, 50019, Italy; 5Univ. of California, Davis, Dept.
of Plant Sciences, Davis, CA, 95616
3
Sixty-two persimmon selections, including 16 Italian, 9 Spanish, 16
Japanese, 6 Korean, and 5 Chinese cultivars, were evaluated for genetic differences by AFLP analysis. Four-hundred-seventy characters
were scored. Similarities were calculated by the method of Nei and
Li. Relationships among cultivars were evaluated by UPGMA clustering and neighbor joining. Most cultivars were quite diverse (0.60 to
0.80 similarity between cultivars), while similarities among groups
were generally less than 0.60. Both UPGMA and neighbor joining
produced clusters for the European and Asian cultivars. Spanish and
Italian cultivars did not cluster, while Chinese and Korean cultivars
formed distinct groups. The diversity within groups was greater than
the diversity between groups. In addition, the presence of several
Japanese cultivars in the European group and Spanish cultivars in the
Asian group suggest that similar, but diverse progenitors were used in
the development of the current cultivars. Duplicate accessions of ‘Kaki
Tipo’ from different sources were clearly different by AFLP pattern
(similarity less than 0.85).
HORTSCIENCE, VOL. 40(4), JULY 2005
6/20/05 5:00:58 PM
Poster Session 11—Controlled Environments
Poster Hall–Ballroom E/F
(294) Radiation Cycle Affects Biomass Production and
Carotenoid Accumulation in Kale
Mark G. Lefsrud*, Dean A. Kopsell
University of Tennessee, 252 Plant Sciences Building, Knoxville, TN, 37996-4561
Plant growing systems have consistently utilized the standard Earth day
as the radiation cycle for plant growth. However, the radiation cycle
can easily be controlled by using automated systems to regulate the
exact amount of time plants are exposed to irradiation (and darkness).
This experiment investigated the influence of different radiation cycles
on plant growth, chlorophyll and carotenoid pigment accumulation
in kale (Brassica oleracea L. var. acephala D.C). Kale plants were
grown in growth chambers in nutrient solution culture under radiation
cycle treatments of 2, 12, 24, and 48 h, with 50% irradiance and 50%
darkness during each time period. Total irradiation throughout the experiment was the same for each treatment. Radiation cycle treatments
significantly affected kale fresh mass, dry mass, chlorophyll a and b,
lutein, and beta-carotene. Maximum fresh mass occurred under the 2-h
radiation cycle treatment. The maximum dry mass occurred under the
12-h radiation cycle treatment, which coincided with the maximum
accumulation of lutein, beta-carotene, and chlorophyll a, expressed on
a fresh mass basis. The minimum fresh mass occurred during the 24 h
radiation cycle treatment, which coincided with the largest chlorophyll b
accumulation. Increased levels of chlorophyll, lutein and beta-carotene
were not required to achieve maximum fresh mass production. Environmental manipulation of carotenoid production in kale is possible.
Increases in carotenoid concentrations would be expected to increase
their nutritional contribution to the diet.
(295) Measuring and Reporting Growing Conditions in
Controlled Environments
Marc W. van Iersel*
University of Georgia, Department of Horticulture, Athens, GA, 30602
Do you accurately measure and report the growing conditions of
your controlled environment experiments? Conditions in controlled
environment plant growth rooms and chambers should be reported
in detail. This is important to allow replication of experiments on
plants, to compare results among facilities, and to avoid artefacts due
to uncontrolled variables. The International Committee for Controlled
Environment Guidelines, with representatives from the U.K. Controlled Environment Users’ Group, the North American Committee
on Controlled Environment Technology and Use (NCR-101), and
Australasian Controlled Environment Working Group (ACEWG), has
developed guidlines to report environmental conditions in controlled
environment experiments. These guidelines include measurements of
light, temperature, humidity, CO2, air speed, and fertility. A brochure
with these guidelines and a sample paragraph on how to include this
information in a manuscript will be available.
(296) Effects of Lighting Intensity on the Yield of Tomato
and Pepper Crops Grown under Space Station (ISS)
Environmental Conditions
Matthew Sisko*1, Jeffrey Richards1, Sharon Edney1, Neil Yorio1,
Gary Stutte1, Raymond Wheeler2
1
Dynamac Corporation, Food and Crop Systems, Kennedy Space Center, FL, 32899;
NASA Biological Sciences, Kennedy Space Center, FL, 32899
2
Of the many environmental variables, light intensity (PPF) has primary
effect on photosynthesis and significantly influences crop yield. With
the eventual use of a crop production system on the International Space
Station (ISS), Mars transit vehicle, or in a lunar/Martian habitat, there
exists certain engineering constraints that will likely affect the lighting
intensity available to plants. Tomato and pepper are candidate crops being
considered by NASA that were selected based on their applicability to
such mission scenarios. To study the effects of lighting intensity, tomato
HORTSCIENCE, VOL. 40(4), JULY 2005
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POSTERS–MONDAY
18 July 2005, 1:15–2:00 p.m.
(Lycopersicon esculentum L. cv. Red Robin) and pepper (Capsicum
annuum L. cv. Hanging Basket) plants were grown under cool-white
fluorescent (CWF) lamps with light intensities of 8.6, 17.2, or 26 mol·m2 -1
·d , with a constant air temperature of 25 °C, 65% relative humidity,
and CO2 supplementation of 1200 μmol·mol-1 in order to duplicate
conditions plants might be subjected to in an open environment of a
space cabin. Following 105 days of growth, edible and total mass for
both tomato and pepper increased with increasing light levels. Fruit
development and time to ripening was also affected by light treatments.
The effects of lighting when combined with other environmental factors typical of spaceflight systems will help define crop production for
future missions that incorporate plant-based life support technologies.
(297) Continuous Fogging using a Nozzle with an Upward
Air Stream Contributes to Steady Air Temperature
during Greenhouse Cooling
Hiromi Toida*1, Toyoki Kozai1, Handarto 1, Katsumi Ohyama2
1
Chiba University, Faculty of Horticulture, Matsudo, Chiba, 271-8510, Japan; 2Tottori
University, Arid Land Reserch Center, Tottori, 680-0001, Japan
Fogging systems are still not widely used for greenhouse cooling,
primarily due to their low fog : evaporation ratio, resulting in a low
cooling efficiency and a high risk of pathogen expansion caused by
excess wetness of plant foliage. The fogging is operated intermittently
because of these problems. Consequently, the air temperature and
relative humidity fluctuates inside the greenhouse. If nozzles with a
high fog : evaporation ratio are employed, the fogging can be operated
continuously. By continuous fogging, steady air temperature and relative
humidity can be achieved inside the greenhouse. In our previous study
under indoor conditions, a high fog : evaporation ratio was achieved
by installing two small fans close to a conventional upright nozzle in
order to obtain an upward air stream. The objective of this study was
to draw a comparison between the environmental conditions inside a
greenhouse with the continuous fogging with small fans and that with
the conventional intermittent fogging without fans. Reduced fluctuation of the air temperature and relative humidity inside the greenhouse
were observed in the case of continuous fogging as compared with that
observed in the case of intermittent fogging. The air temperature inside
the greenhouse during cooling was lower than that before cooling in
both methods. In the case of continuous fogging, the adjustment of
the amount of fogged water will provide the desired environmental
conditions inside the greenhouse.
(298) Lighting Intensity and Temperature: How They
Affect the Yield of Salad Crops Grown under ISS Baseline
Environmental Conditions
Jeffrey Richards1, Sharon Edney1, Neil Yorio*1, Gary Stutte1,
Matthew Sisko,1 Raymond Wheeler2
1
Dynamac Corporation, Food and Crop Systems, Kennedy Space Center, FL, 32899;
NASA Biological Sciences, Kennedy Space Center, FL, 32899
2
Environmental factors such as light intensity (PPF) and/or air temperature
may be limiting engineering constraints in near or long-term space missions. This will potentially affect NASA’s ability to provide either dietary
augmentation to the crew or maintain a large-scale bioregenerative life
support system. Crops being considered by NASA to provide supplemental food for crew consumption during such missions consist primarily
of minimally processed “salad” species. Lettuce (Lactuca sativa L. cv.
Flandria), radish (Raphanus sativus L. cv. Cherry Bomb II), and green
onion (Allium fistulosum L. cv. Kinka) are being evaluated under a range
of PPF and temperature environments likely to be encountered in space
systems. Plants were grown for 35 days under cool-white fluorescent
(CWF) lamps with light intensities of 8.6, 17.2, or 26 μmol·m-2·d-1, at
air temperatures of 25 and 28 °C, and 50% relative humidity, and 1200
μmol·mol-1 CO2. Regardless of temperature, all three species showed
an increase in edible mass with increasing light levels. When grown at
28 °C, edible mass of radish was significantly reduced at all lighting
intensities compared to 25 °C, indicating a lower optimal temperature
for radish. Understanding the interactions of these environmental factors
on crop performance is a critical element to defining future missions
that incorporate plant-based life support technologies.
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(299) Comparison of Growth of Salad Crops under ISS
Baseline Environmental Conditions in Mixed Crop versus
Monoculture Hydroponic Systems
Sharon Edney*, Jeffrey Richards1, Matthew Sisko1, Neil Yorio1,
Gary Stutte1, Raymond Wheeler2
1
Dynamac Corporation, Food and Crop Systems, Kennedy Space Center, FL32899; 2NASA
Biological Sciences, Kennedy Space Center, FL 32899
Development of a crop production system that can be used on the
International Space Station, long duration transit missions, and a lunar/Mars habitat, is a part of NASA’s Advanced Life Support (ALS)
research efforts. Selected crops require the capability to be grown
under environmental conditions that might be encountered in the open
cabin of a space vehicle. It is also likely that the crops will be grown
in a mixed-cropping system to increase the production efficiency and
variety for the crew’s dietary supplementation. Three candidate ALS
salad crops, radish (Raphanus sativus L. cv. Cherry Bomb II), lettuce
(Lactuca sativa L. cv. Flandria) and bunching onion (Allium fistulosum L. cv. Kinka) were grown hydroponically as either monoculture
(control) or mixed-crop within a walk-in growth chamber with baseline
environments maintained at 50% relative humidity, 300 μmol·m-2·s-1
PPF and a 16-hour light/8-hour dark photoperiod under cool-white
fluorescent lamps. Environmental treatments in separate tests were
performed with either 400, 1200, or 4000 μmol·mol-1 CO2 combined
with temperature treatments of 25 °C or 28 °C. Weekly time-course
harvests were taken over 28 days of growth. Results showed that none
of the species experienced negative effects when grown together under
mixed-crop conditions compared to monoculture growth conditions.
the National Aeronautics and Space Administration’s (NASA) goal of
supporting humans on near-term space missions, such as on the International Space Station. Small areas of salad crops are ideal candidates
for growing in limited volumes, and would provide a source of fresh
food to enhance the crew’s nutrition. Baseline controlled environment
studies were initiated to evaluate the response of eight carrot cultivars
(‘Baby Mini’, ‘Nantes Touchan’, ‘Danvers 126’, ‘Kundulus’, ‘Nanco
Hybrid’, ‘Thumbelina’, ‘Early Nantes’, and ‘Juwarot’) to growth
and yield in hydroponics. Seeds were sown in moist arcillite and
transplanted into growth troughs (0.15 × 0.15 × 1.2 m) after 18 days
in reach-in growth chambers, and nutrients continuously supplied by
a half-Hoagland solution. Growth chambers conditions included 300
μmol·m-2·s-1 photosynthetic photon flux, 16/8 photoperiod, a constant
25 °C and relative humidity of 50%. Plants were harvested at about
80 days. All eight cultivars grew well in the hydroponic system. Seven
cultivars produced greater shoot fresh than root mass except ‘Baby Mini’,
which showed the reverse. ‘Danvers 126’, followed by ‘Nanco Hybrid’
and ‘Nantes Touchan’, produced highest root yields. The β-carotene
content varied by cultivars. The highest level of 10,400 IU/100 g was
obtained for ‘Thumbelina’, followed by ‘Baby Mini’ (8040 IU/100 g),
‘Juwarot’ (6160 IU/100g), and ‘Early Nantes’ (5210 IU/100 g), and
the lowest by ‘Nantes Touchan’ (3510 IU/100 g). These results show
that while carrots adapted well to growth in hydroponics, carotene, a
major nutrient, was at relatively low levels.
(302) Photoautotrophic Micropropagation Systems
Demonstrate Rooting Stage Improvement of Laelia
purpurata var. alba
(300) Effect of Planting Density, CO2, and Harvest
Intervals on Biomass of Three Allium Species
Hope Jones*, Chieri Kubota
Amanda L. Broome*, Ellen B. Peffley
In vitro culture of orchid plantlets within conventional photomixotrophic micropropagation (PMM) systems (sucrose containing media in
a non-enriched CO2 environment) often induces vigorous growth and
multiplication. However, transition to ex vitro conditions frequently
results in significant plantlet loss during the acclimatization process.
Recent studies investigating micropropagation within photoautotrophic
(PAM) systems (sucrose-free media in enriched CO2 conditions) have
demonstrated improved plantlet survival during the acclimatization
period due to greater root growth and stomata adaptation. Laelia
purpurata var. alba, an orchid with many endangered relatives, was
chosen as a model orchid species to investigate if plantlet culture within
PAM in vitro systems has the potential to improve propagation success
and ex vitro survival of endangered Laelia species. Protocorm-like
bodies with developed two fully extended leaves were transferred
into PMM (photosynthetic photon flux 50 μmol·m-2·s-1 under nonenriched CO2 conditions) and PAM (photosynthetic photon flux 150
μmol·m-2·s-1, CO2 level enriched to 1500 μmol·mol-1) systems. After
6 weeks, plantlet rooting within the PMM system was variable and
inconsistent, while all PAM plantlets produced healthy robust root
systems. Average fresh weights and percent shoot development were
not significantly different between treatments. Induction of improved
root growth by PAM systems may improve orchid plantlet survival
rates during acclimatization and advance our ability to increase endangered orchid populations.
Texas Tech Univeristy, Plant & Soil Science, Lubbock, TX, 79409
This research evaluated, for the NASA ALS program, the effect of
spacing and harvest intervals on edible biomass of green salad onions grown at two CO2 levels. Shoot biomass of Japanese bunching
onion (Allium fistulosum), bulbing onion (A. cepa), and chives (A.
schoenoprasum) grown at 10-, 15-, and 20-mm spacings harvested at
7- and 14-day intervals, seven and four harvests, respectively, over 70
days were compared. Onions were grown hydroponically in growth
chambers, 16-hour light/8-hour dark, 24/20 °C, 75/99% at ~450 and
1200 ppm CO2. The design was a completely randomized block with
repeated measures; subsamples were plants completely surrounded by
neighboring plants. Weekly shoot removal began 28 days after planting
(dap); destructive harvest was 70 dap. Length and diameter of longest
leaf, weight, and number of leaves/tillers were taken at each harvest;
bulb caliper and weight were taken 70 dap. Bunching and bulbing
onion leaves were longest at 28 dap and decreased over time; chives
were slow to establish but 70 dap had longest leaves. Leaf diameter
of all species increased as spacing increased. At 56 through 70 dap
chives at all three spacings produced more leaves. Mean weight of
shoots differed significantly at 20-mm spacing: chives the least, bulbing
onion the most. Bulb weight for bulbing onion and chives increased
with increased spacing; bulbing onion weighed significantly more at
15- and 20-mm spacings compared to the other species and spacings.
Chives grown at 20-mm spacing had tillering clumps of rhizomes. Total
edible biomass weight (bulb, pseudostem, and shoots) of bulbing onion
grown at 10-mm spacing exhibited similar ontogeny to chives grown at
10- and 15-mm spacings; bulbing onion grown at 20-mm spacing had
the most edible biomass. On average, biomass was greatest in plants
grown at 1200 ppm CO2.
(301) Screening Carrot Cultivars for Adaptability to
Growth in a Nutrient Film Hydroponics System
Desmond Mortley*1, Jill Hill2, Conrad Bonsi2, Walter Hill2,
Carlton Morris2
1
Tuskegee University, Agricultural Sciences, Tuskegee, Alabama, 36088; 2Tuskegee
University, Agricultural Experiment Station, Tuskegee, AL, 36088
Tuskegee University is conducting research on salad crops as part of
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The University of Arizona, Department of Plant Sciences, Tucson, AZ, 85721
(303) Challenges of Organic Hydroponic Production of
Strawberries (Fragaria ×ananassa)
Brandon Jewell*, Chieri Kubota
The University of Arizona, Department of Plant Sciences, Tucson, AZ, 85721
Feasible protocols for organic hydroponic production of strawberry
are necessary and this study compares the yield and fruit quality of
organic and conventional inorganic hydroponic production. Some
issues identified with organic hydroponic strawberry production are:
1) dominant ammonium nitrogen form; 2) solution alkalinity; and
3) dissolved oxygen level of nutrient solution. Eighty bare-rooted
‘Diamante’ plantlets were planted in coconut fiber pots with a mixture
of coconut coir (30%) and perlite (70%) and grown in a modified
nutrient film technique system inside a polycarbonate greenhouse.
The organic nutrient solution contains mostly ammonium nitrogen
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(304) Effects of Supporting Material and Nutrient Supply
Cycle on the Growth of Potato Plantlets in a Nutrientcirculated Micropropagation System
Jung Eek Son*, Yil Jang, Jung Hyuk Seo
Seoul National University, Plant Science, Silim 9-dong, Seoul, 151-921, Republic of
Korea
Supporting materials for rooting have a considerable influence on the
growth and quality of in vitro plantlets. Various supporting materials
(rockwool, perlite, vermiculite, and polyurethane) and nutrient supply
cycles (12, 24, 36, and 48 hours) were examined to find the optimum
conditions for photoautotrophic micropropagation of potato plantlets in
the nutrient-circulated micropropagation (NCM) system. In the NCM
system, nutrient solution was circulated between the culture vessel and
the nutrient reservoir. A plug cell tray with 70 plantlets was placed inside.
The number of air exchanges was 10 hours under forced ventilation.
Nodal leafy cuttings of plantlets were cultured at CO2 concentrations
(mol·mol-1)/PPFs (mol·m-2·s-1) of 350/80, 700/120, and 1500/250 on
day 5-11, 12-18, and 19-28, respectively, for all treatments. All growth
factors of in vitro plantlets grown for 28 days using rockwool, perlite
and vermiculite were greater than those grown using polyurethane. Dry
weight of plantlets grown using rockwool was eight times greater than
those grown using polyurethane. The same results were obtained in
the growth and survival percentages 14 days after transplanting to ex
vitro conditions. Optimum nutrient supply cycles were 12, 24, and 48
hours when perlite, rockwool, and vermiculite were used as supporting
materials, respectively. It was considered that the range of optimum
nutrient supply cycle was affected by water retention characteristics
of supporting materials. This study proved that the supporting material and the nutrient supply cycle were very important environmental
factors in photoautotrophic mass propagation.
(305) Influence of Hypobaria on Gas Exchange and
Growth of Lettuce for Advanced Life Support Systems
(ALS)
Chuanjiu He1, Fred T. Davies*1, Ronald Lacey2
1
Texas A&M University, Dept. of Horticultural Sciences, College Station, TX, 778432133; 2Texas A&M University, Biological and Agricultural Engineering, College Station,
TX, 77843-2133
There are advantages in growing plants under hypobaric (reduced
atmospheric pressure) conditions in biomass production for extraterrestrial base or space-flight environments. Elevated levels of the plant
hormone ethylene occur in enclosed crop production systems and in
space-flight environments—leading to adverse plant growth and sterility. Objectives of this research were to characterize the influence of
hypobaria on growth and ethylene evolution of lettuce (Lactuca sativa
L. cv. Buttercrunch). Growth was comparable in lettuce grown under
low (25 kPa) and ambient (101 kPa) total gas pressures. However, tip
burn occurred under ambient, but not low pressure—in part because
of adverse ethylene levels. Under ambient pressure, there were higher
CO2 assimilation rates and dark respiration rates (higher night consumption of metabolites) compared to low pressure. This could lead
HORTSCIENCE, VOL. 40(4), JULY 2005
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to greater growth (biomass production) of low pressure plants during
longer crop production cycles.
(306) NFT versus Subirrigation: I. Yield and Water Use
Efficiency of Tomato Grown in Closed Soilless Systems
under Salinity or Water Stress
Francesco Montesano*1, Gianfranco Favuzzi1, Angelo Parente2,
Francesco Serio2, Pietro Santamaria1
1
2
University of Bari, Department of Crop Science, via Amendola 165/A, Bari, 70126, Italy;
CNR, Institute of Science of Food Production, via Amendola 122/o, Bari, 70126, Italy
Sustainability of the soilless greenhouse system is under discussion
in open cycle systems, where excess nutrient solution (NS) draining
from the substrate is released into the environment. Closed growing
systems (CGS) lead to the saving of water and fertilizers. The aim
of this research was to compare two CGS: nutrient film technique
(NFT) and trough-bench technique [Subirrigation (SUB)]. We report
the results of yield and water use efficiency (WUE) of tomato (Lycopersicon esculentum Mill. cv. Kabiria) plants. NFT plants were grown
with two electrical conductivity (EC) levels (2-4 and 6-8 dS·m-1) of
NS (its highest EC was obtained by increasing all the ions therein).
In the SUB system, two water tensions (-4 and –8 kPa) of susbtrate
were compared; a NS with an electrical conductivity level of 2 dS·m-1
was used. The tensions were measured through tensiometers. Tomato
plants were transplanted at the fourth to fifth true-leaf stage into pots
containing 8 L of perlite for SUB. In both CGS, the plants were placed
on steel gullies (slope of 2%). Six clusters per plant were harvested.
Total and commercial yield were not influenced by the CGS (on
average, 1959 and 1853 g/plant, respectively). The average weight
of the fruit was lower in the SUB system’s plants (40 vs. 43 g/fruit,
respectively, for SUB and NFT). Salinity and water stresses resulted
in a reduction of 26% of the yield and 16% of the average weight of
fruits. The WUE was higher in SUB than NFT (30.7 vs. 26.0 g·L-1,
respectively). Salinity stress reduced WUE (29.4 v.s 22.6 g·L-1 with
2–4 and 6–8 dS·m-1, respectively), whereas water stress did not.
POSTERS–MONDAY
and little nitrate nitrogen. To enhance colonization and activities of
nitrifying bacteria, coconut fiber mats were placed in the organic nutrient solution reservoir. A similar system was also introduced for stock
solution pre-conditioning where nitrification and pH stabilization were
achieved before application to the strawberry plantlets. The organic
nutrient solution prior to pre-conditioning had only 1.53 mg·L-1 nitrate
nitrogen, although the nitrate nitrogen level increased to 63.2 mg·L-1
after pre-conditioning. The organic nutrient solution pH was 4.5 initially, 8.5 after 24 hours of pre-conditioning, and finally, shifted to and
stabilized at 5.7–5.9 after 3 days. Dissolved oxygen level is critical for
both nitrifying bacteria activities and plantlet root growth; therefore,
oxygen enrichment was achieved by constantly aerating the nutrient
solution in the reservoir, which raised the oxygen level from 2.5 to 7.4
mg·L-1. Comparisons of yield and quality of strawberry fruits between
organic and inorganic nutrient solutions will be presented and further
improvements of hydroponic systems will be discussed.
(307) NFT versus Subirrigation: II. Tomato Fruit Quality
Grown in Closed Soilless Systems under Salinity or
Water Stress
Francesco Montesano*1, Cristina Ferulli,1 Angelo Parente2,
Francesco Serio2, Pietro Santamaria1
1
2
University of Bari, Department of Crop Science, via Amendola 165/A, Bari, 70126, Italy;
CNR, Institute of Science of Food Production, via Amendola 122/O, Bari, 70126, Italy
Nutrient solutions (NS) containing moderate to high concentrations
of salts are frequently supplied to improve the taste of tomato fruits
grown in soilless systems. The aim of this study was to determine
whether salinity and water stress affect the tomato fruit quality
similarly. The research was conducted in Mola di Bari, Italy, during
Autumn 2004, and compared the nutrient film technique (NFT) with
the trough-bench technique [Subirrigation (SUB)] in terms of tomato
(Lycopersicon esculentum Mill. cv. Kabiria) fruit quality. In the NFT,
the plants were grown with two electrical conductivity (EC) levels (2–4
and 6–8 dS·m-1) of NS. The highest EC was obtained by increasing all
the ions in the NS. In the SUB system, two water tensions (-4 and -8
kPa) of substrate (perlite) were examinated. At harvest, in each cluster
(six/plant), fruit dry matter (DM) and total soluble solids (TSS) were
determinated. In the fourth and sixth cluster, vitamin C content and
titratable acidity were determined. Total yield was not influenced by
either soilless system, while the average weight of the fruit was lower
in the SUB. The DM and TTS were influenced by soilless system
(on average, 6.6 vs 7.3 g/100 g of fresh matter and 5.3 vs. 5.9 °Brix,
with NFT and SUB, respectively). Both of the stresses resulted in the
increase of DM and TSS, principally in SUB (water stress) in respect
to NFT (salinity stress), while vitamin C and titratable acidity were
not influenced by soilless system or water/salinity stress (25.2 mg/100
g fresh matter and 0.45 g/100 mL of citric acid juice, respectively).
Results of NFT with the highest EC of NS exceeded 9 dS·m-1, without any stress symptoms in the plants, while EC in the SUB system
remained unchanged (about 2.5 dS·m-1).
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(308) Irrigation Strategies for Rockwool-grown
Greenhouse Tomatoes
(64) Effect of Plug Flats on Posttransplant Growth and
Prevention of Stunting
Athanasios Papadopoulos1, Uttam Saha*1, Xuiming Hao1,
Shalin Khosla2
Aliya Donnell*, John Dole
1
Agriculture and Agri-Food Canada, Greenhouse and Processing Crops Research Centre,
Harrow, Ontario, N0R 1G0, Canada; 42 Ontario Ministry of Agriculture and Food, Harrow,
Ontario, N0R 1G0, Canada
In rockwool-grown greenhouse vegetables, unsatisfactory spatial root
development, rapid root collapse, and increased incidence of root diseases are very common. Improved water management could alleviate
these problems to some extent, because this could favorably modify
water-air distribution in the slab, thereby improving greenhouse vegetable yield and quality. The present study tested six irrigation strategies
on the productivity of rockwool-grown tomatoes (cv. Rapsodie) during
Jan.º–Aug. 2004. The four treatments, based on electronic Grodan?
water content meters (WCMs), received irrigations when the slab
water content (SWC) was ≈60%, 70%, 80%, and 90% while the other
two treatments, based on balances, applied irrigations after a 700- or
500-g loss in the daily-adjusted slab weight (LDASW). Initially, we
noticed a heterogeneous EC build-up in the slabs across various treatments, which probably distorted the expression of treatment effects (if
any) on plant growth, yield, and water use. To minimize this problem,
an EC control strategy of applying extra irrigation was devised and
adopted in two sequential phases: 1) application of a 30-minute-long
extra irrigation twice a week (for 7 weeks); and 2) extra irrigation(s)
using the irrigation control routine of an Argus computer when the
slab EC was ≈3.5 mS/cm (for 5 weeks). Slab EC was well controlled
in both these phases and we observed significant treatment effects on
root growth and marketable yield. Analyzing the results, we concluded
that irrigating at 70% to 80% SWC was best for maximum root growth
as well as marketable yield. The two irrigation treatments based on the
700- and 500-g LDASW were well maintained and performed equally
well, producing marketable yields comparable to those produced by
irrigating at 70% and 80% SWC.
North Carolina State University, Horticultural Science, Raleigh, NC, 27695
Plug production is an integral part of today’s floriculture industry.
However, if seedlings are held in plug flats for too long, they may not
return to a normal growth rate after transplanting. Stunting may render
plants unsuitable for sale. Common bedding plant and cut flower species were grown in 288-plug flats to determine how long plugs could
be held in the flats and still regain a normal growth rate and desirable
growth form after transplanting. Species surveyed included: Antirrhinum, Begonia, Brassica, Callistephus, Celosia, Consolida, Dianthus,
Eustoma, Gazania, Helianthus, Impatiens, Lycopersicon, Matthiola,
Tagetes, and Viola. Ten randomly selected plugs were transplanted to
15- or 17-cm pots every 1 or 2 weeks for 10 weeks, when root balls
were sufficiently developed to hold together after removal from the flat.
Overall plant height was recorded for all species every 1 or 2 weeks.
Plant diameter was recorded every 2 weeks for Begonia, Celosia,
Eustoma, Helianthus, Impatiens, Lycopersicon, and Tagetes. A plug
was considered to be stunted if it died after transplanting or did not
resume a normal growth rate. Species that exhibited stunting included
Brassica, Callistephus, Celosia, Consolida, Dianthus, and Tagetes. For
example, Consolida seedlings held in the plug flat for 7 weeks after
optimal transplanting time were six times smaller than those that were
transplanted at the optimal time. Several factors were investigated to
determine how they affected the degree of stunting, including: light
quality, root obstruction, nitrogen enrichment prior to transplanting,
gibberellic acid addition prior to transplanting, teasing of the root ball
prior to transplanting, and length of drainage column.
(69) Effects of Photoselective Shadecloths on Growth and
Flowering of Potted Chrysanthemum
Kent D. Kobayashi*
University of Hawaii at Manoa, Tropical Plant & Soil Sciences, Honolulu, HI, 96822
Poster Session 12—Floriculture Production
18 July 2005, 1:15–02:00 p.m.
Poster Hall–Ballroom E/F
(63) Production Systems for Celosia in a Tobacco
Transplant Greenhouse
Carl E. Niedziela, Jr.*, Guochen Yang
North Carolina A&T State University, Natural Resources and Environmental Design,
Greensboro, NC, 27411
Plug seedlings of Celosia cristata L. ‘Persimmon Chief’ were planted
in four production systems (harvest lugs, lay-flat bags, pots, and polystyrene trays) on 7 May 2004. Production systems were randomized
in a Latin-square design with four replications of each system. Each
treatment plot was 0.7 m × 1.1 m. Planting density was 31 plants/m2.
The harvest lugs were 55 cm × 37 cm × 16 cm. The lay-flat bags were
114 cm × 30 cm × 3 cm. The pots were 25 cm bulb pans. The polystyrene trays were 67 cm × 34 cm × 5 cm and contained 32 square cells.
All of the containers were filled with the same tobacco germination
media. The plants in the harvest lugs, lay-flat bags and pots were irrigated daily with 150 mg·g-1 N from 20N–4.4P–16.6K. The plants in
the polystyrene trays were floated on a solution of 150 mg·g-1 N from
20N–4.4P–16.6K. Float solutions were monitored and adjusted weekly
for volume and fertilizer concentration. Individual stems were harvested
at the appropriate stage of development for market. The fresh weight,
stem length and flower diameter of individual stems were recorded.
Stems produced in float trays had the lowest fresh weight (162.2 g).
Stems grown in harvest lugs (363.5 g) weighed more than those in pots
(298.4 g) but not lay-flat bags (338.4 g, LSD0.05 = 42.7). Stems grown
in float trays (88.8 g) were shorter than lay-flat bags (121.5 g), harvest
lugs (120.5 g), and pots (113.5 cm, LSD0.05 = 10.5). Flower diameter did
not differ between production systems (mean diameter = 7.2 cm).
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final6_20July HS.indb 1012
Controlling plant height is an important practice in the ornamental
plant industry. Though commonly used, growth regulators are expensive, and there are concerns about environmental consequences
and safety of workers. Alternative ways of controlling growth may
be advantageous. The objective of this study was to determine the
effects of photoselective shadecloths on the growth and flowering of
‘Arezzo’ chrysanthemum. One-month-old potted ‘Arezzo’ chrysanthemum plants were grown in a saranhouse in chambers built with PVC
(polyvinyl chloride) pipe covered with 30% shadecloths—red, blue,
gray, and black (control). The blue shadecloth was more effective in
reducing plant height, with no differences among the other shadecloths.
Plant canopy dimensions—greatest canopy width and average canopy
width—did not show any differences among the shadecloths. The red
shadecloth was more effective in hastening flowering, followed by the
blue shadecloth. This was evident by flowering first occurring with
the red shadecloth and initially the greatest number of buds showing
color. Additionally, the red shadecloth had the highest proportion of
the number of flowers to the combined number of flowers and buds
showing color. Specifically, the total number of flowers was similar
to the total number of buds showing color. In contrast with the other
shadecloths, there was a greater number of buds showing color than the
number of flowers. The most buds showing color occurred with the gray
shadecloth. The three shadecloths resulted in a greater number of the
combined buds showing color and flowers than the black shadecloth.
In conclusion, photoselective shadecloths may provide an alternative
to controlling plant height and altering the flowering pattern of potted
chrysanthemums.
(65) Evaluation of Curcuma as Potted Plant and Cut
Flower
Mark Roh*1, Roger Lawson2, Jong Suk Lee3, Jeung Keun Suh,4
Richard A. Criley5, Pimchai Apavatjrut6
1
Floral and Nursery Plants Research Unit, USDA, ARS, National Arboretum, B-010A,
Beltsville, MD, 20705; 2Retired; 3Dept. of Horticulture, Chungnam National University,
HORTSCIENCE, VOL. 40(4), JULY 2005
6/20/05 5:01:04 PM
Sixteen accessions of Curcuma germplasm and several selected accessions of Curcuma were evaluated for use as potted plants or as
cut flowers. Curcuma alismatifolia Gagnep. and C. thorelii Gagnep.
‘Chiang Mai Snow’ met standards for cut flower and pot plant use,
respectively. Furthermore, C. parviflora Will. ‘White Angel’ proved
to be a good selection for potted plant production. Optimum storage
temperatures of rhizomes were studied in relation to greenhouse forcing
and carbohydrate changes. It is recommended to store rhizomes at 25
to 30 °C after harvest for 2 to 3 months to break dormancy. Plants of
C. parviflora ‘White Angel’ flowered in 50 to 89 days and C. ‘CMU
Pride’ flowered in 104 days after potting, and were acceptable as
potted plants. Plants of C. alismatifolia flowered 96 to 133 days after
potting with floral stem length suitable for use as a cut flower. A high
level of boron or manganese may cause the burn at the margin of the
leaves (marginal leaf burn) observed on old leaves of ‘CMU Pride’ at
flowering. The level of ethanol-soluble fructose, glucose, and sucrose
in elongated rhizomes with emerged short shoots of Curcuma was
higher than the level in rhizomes and increased as storage temperatures increased. Accelerated leaf emergence may be associated with
the increase in the glucose and fructose content. Based on the similar
morphological characters between C. thorelli ‘Chiang Mai Snow’ and
C. parviflora ‘White Angel’, identification of Curcuma accessions is
required in future studies.
(66) Modeling Flower Bud Development of Impatiens
hawkeri and I. walleriana
James E. Faust*, Kelly P. Lewis
Clemson University, Horticulture, Clemson, SC, 29634
Three cultivars of New Guinea impatiens (Impatiens hawkeri) and two
cultivars of double impatiens (I. walleriana) were grown in greenhouses
maintained at 15, 20, and 25 °C. Bud diameter was measured twice
weekly on five plants per cultivar from the time of visible bud to open
flower. The experiment was repeated twice. For New Guinea impatiens,
the time from visible bud (1-mm diameter) to open flower was 31, 43,
and 72 days at 25, 20 and 15 °C, respectively. Flower bud diameter
increased linearly as the bud expanded from 1 to 9 mm. For double
impatiens, the time from visible bud (1-mm diameter) to open flower
was 25, 30, and 58 days at 25, 20 and 15 °C, respectively. Flower bud
diameter increased at an increasing rate (curvilinear response) as the
bud expanded from 1 to 8 mm. These models are currently in commercial use to aid greenhouse growers in accurately timing crops for
specific market dates.
(67) Survey at Poinsettia Open House Reveals Preferred
Cultivars
C. Catanzaro, S. Bhatti*, S. Muhammad, S. Abdullah
Tennessee State University, Institute of Agricultural and Environmental Research, Nashville, TN, 37209
A high quality finished plant from each of 22 cultivars was displayed at
a poinsettia [Euphorbia pulcherrima Willd. ex Klotzsch] open house at
Tennessee State University in Dec. 2004. The cultivars represented the
range of flower colors, flower traits, and plant vigor available through the
major suppliers Dummen USA, Ecke, Fischer, and Oglevee. Attendees
of the open house completed a written survey (n = 101) in which they
were asked to rate their cultivar preferences. Cultivars (identified only
by an alphabetic letter) were rated by respondents on a Likert-type
scale (1 = strongly dislike to 5 = strongly like). Highly rated cultivars
(mean ≥4) included ‘Freedom Red’, ‘Premium Red’, ‘Nutcracker
White’, ‘Early Orion’, ‘Cortez Electric Fire’, and the new cultivars
‘Visions of Grandeur’ and ‘Kris Krinkle’. Cultivars were also rated
on the price range potential consumers were willing to pay. Respondents were willing to pay the most to purchase ‘Visions of Grandeur’,
which is a vigorous cultivar with large, pillowy, peach-colored bracts.
Overall, traditional red cultivars and large, non-red cultivars were
HORTSCIENCE, VOL. 40(4), JULY 2005
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preferred. Most of the respondents indicated that they purchased red
plants, and color was the most important selection criterion. Results
suggest that although most consumers prefer traditional red cultivars,
women prefer some alternative inflorescence colors and unique bract
shapes more than men.
(68) Ceratostigma plumbaginoides Is an Intermediate-day
Plant
Ki Sun Kim*1, Arthur C. Cameron2, Erik S. Runkle2
1
Seoul National University, Horticulture, Seoul, 151-921, Korea; 2Michigan State University,
Horticulture, East Lansing, MI, 48824
We performed experiments to determine the photoperiodic response of
Ceratostigma plumbaginoides Bunge., or leadwort, which is a low-growing hardy herbaceous perennial native to China with deep gentian-blue
flowers. Tip cuttings were rooted in 72-cell trays and grown under a
24-hour photoperiod for 2 weeks and then transplanted into 11.4-cm
pots and grown for one more week. Plants were then placed under different primary photoperiods (10, 16, or 24 hours) for 4, 6, or 8 weeks,
then transferred to secondary photoperiods (10, 14, 16, or 24 hours) at
a constant 20 °C. Pots were also placed under continuous 10, 14, 16, or
24 hours. Nearly all plants flowered under all treatments except under
continuous 10- or 24-hour photoperiods, in which no plants flowered.
Plants grown under 14 hours flowered earliest (50 days), followed by
plants under the 16-hour primary treatment. The 10-hour primary treatment delayed flowering for as long as its duration, whereas the 16-hour
primary photoperiod initiated rapid flowering, regardless of duration and
subsequent secondary photoperiod. Flowering was also delayed when
the primary photoperiod was 24 hours. Collectively, these responses
indicate that Ceratostigma is an intermediate-day plant.
POSTERS–MONDAY
College of Agriculture and Life Sciences, Daejeon, 305-764, Korea; 4 College of BioResources Science, Laboratory of Floriculture, Dankook University, Cheonan, 330-714,
Korea; 5 Department of Horticulture, University of Hawaii, Honolulu, HI, 96822; 6
Department of Horticulture, H.M. the King’s Initiative Center, Chiang Mai University,
Chiang Mai, 50200, Thailand
(70) Hydroponic Sunflower Production as Influenced by
Cultivar, Nitrogen Fertilization, and Root-knot Nematode
Infestation
Yan Chen*1, Donald Merhaut2, J. Ole Becker3
1
LSU AgCenter, Hammond Research Station, Hammond, LA, 70403; 2UC Riverside,
Botany and Plant Sciences; 3UC Riverside, College of Natural and Agricultural Sciences
Nematology
Nitrogen (N) fertilization is critical for successful production of cut
flowers in a hydroponic system. In this study, two sunflower cultivars:
single-stand ‘Mezzulah’ and multi-stand ‘Golden Cheer’ were grown
under two N fertilization rates: 50 mg·L-1 and 100 mg·L-1 in a recirculating hydroponic system. At the same time, ‘Mezzulah’ sunflowers
were biologically stressed by exposing each plant to 2000 second-stage
juveniles of the plant parasitic nematode Meloidogyne incognita, race 1.
The experiment was conducted in May and repeated in Sept. 2004, and
plant growth and flower quality between control and nematode-infested
plants were compared at the two N rates. The two cultivars responded
differently to fertilization treatments. With increasing N rate, the dry
weight of ‘Mezzulah’ increased, while that of ‘Golden Cheer’ decreased.
Flower size and harvest time were significantly different between the
two cultivars. However, N had no effect on flower quality and harvest
time. Flower quality rating suggests that quality cut stems can be
obtained with 50 mg·L-1 N nutrient solution. Nematode egg count suggests that plants in the nematode treatment were successfully infested
with Meloidogyne incognita, however, no significant root galling was
observed, and plant growth and flower quality were not affected by
nematode infestation.
(71) Day Length Controls Flowering and Height of
Sunflower
Meriam Karlsson*, Jeffrey Werner
University of Alaska Fairbanks, Department of Plant, Animal and Soil Sciences, Fairbanks,
AK, 99775-7200
Flowering in response to day length was identified for sunflower (Helianthus annuus L. ‘Pacino Gold’). Germination and seedling development occurred at 20 °C and long days (LD, 16 hours) following direct
seeding into 10-cm pots. Sixteen days after seeding, plants were placed
at LD or short days (SD, 8 hours), 20 °C and 8 mol·d-1·m-2. Flowering
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was recorded at the stage of reflexed petals after 48 SD. At the time
of flowering in SD, flower buds were of minute size under LD. Plants
started at LD, and moved to SD after 1, 2, or 3 weeks, flowered at similar
times as those grown under uninterrupted SD conditions. Four initial
weeks of LD delayed flower development with 7 days, compared to a
continuous SD environment. On the other hand, 2 to 3 weeks of initial
SD followed by LD hastened flowering with 5 to 10 days. With increasing number of early LD from 1 to 4 weeks, plant height at flowering
doubled from 20 to 40 cm. Average plant height in continuous SD was
18 cm. Plants grown exclusively or moved to LD after 1 to 4 weeks of
SD were similar in height to plants finished at SD with 4 initial weeks
of LD. Combinations of SD and LD may be used to manage height and
rate of development in the sunflower ‘Pacino Gold’.
(72) Effects of Photoselective Shadecloths on Growth of
Potted Orchids
Kent D. Kobayashi*1, Edwin F. Mersino2
1
University of Hawaii at Manoa, Tropical Plant & Soil Sciences, Honolulu, HI, 96822;
University of Hawaii at Manoa, Plant & Environmental Protection Sciences, Honolulu,
HI, 96822
2
The objective of this study was to determine the effects of photoselective
shadecloths on the growth of potted orchids. At an orchid nursery in
Waianae (Oahu), 10 kinds of orchids were grown under four 30%
shadecloths—red, blue, gray, and black (control). At the University of
Hawaii Magoon Facilities (Oahu), two kinds of orchids were grown in
a saranhouse in chambers built with PVC pipe and covered with the
four 30% shadecloths. At the orchid nursery, for the two orchids that
plant height measurements were taken, 11055 (Epi. Joseph Glow-Star
Valley) × Epc. Pele’s Flame ‘Orange Star’ had the greatest percentage
of increase in height under the gray shadecloth. For M-11347 Epidendrum Pompon ‘Pink Ruby’, the three shadecloths resulted in greater
height increases than the control, with the blue shadecloth having the
greatest increase. At the Magoon Facilities, for M-10973 Rhv. Herbert
Kurihara ‘Flori’, the red shadecloth resulted in the largest increase in
plant height compared to the black shadecloth. The gray shadecloth
and blue shadecloth resulted in a smaller increase in plant height. The
black shadecloth had the largest increase in leaf number compared to
the other treatments. Slight leaf loss occurred with the red shadecloth.
For M-10878 Colmanara Sphacetante ‘Evelyn’ AM/AOS, the smallest
increase in plant height was under the blue shadecloth compared to the
black shadecloth, which was similar to the other two shadecloths. Leaf
loss occurred for all treatments, with the three shadecloths having less
leaf loss than the black shadecloth. All treatments had similar numbers
of new shoots. Thus, photoselective shadecloths influenced vegetative
growth, but their effects varied with the orchid.
(73) Is the Shorter Time to Flower for Late-planted
Curcuma alismatifolia Real?
Richard A. Criley*1, Jeff S. Kuehny2
1
University of Hawaii, Tropical Plant and Soil Sciences, Honolulu, HI, 96822; 2Louisiana
State University, Dept. of Horticulture, Baton Rouge, LA, 70803-2120
Several reports suggest that late-planted rhizomes of Curcuma alismatifolia produce their inflorescences in less time than those that have
been planted earlier in the forcing season. Two cultivars of this ginger
species were removed from the ground in late February following a
lengthy dormancy period in the field. About 6 weeks later, after air
drying, weekly plantings were initiated through the end of June. Five
rhizomes per cultivar were planted singly in 15-cm pots in ProMix
BX medium. All plants were forced outdoors under full sun conditions
and an overhead spray stake irrigation system that delivered 200 ppm
each of nitrogen and potassium with each watering. Cultivar differences were apparent. Plant-to-sprout days for the DP and LP cultivars
ranged from 20–51 and 21–57 days, respectively, with means of 3 8 ±
9.2 and 44 ± 11.9 days, respectively, over the 10-week planting cycle.
Sprout-to-flower days showed much less difference with ranges of
61–75 and 58–72 days for DP and LP and means of 69 ± 4.3 and 66 ±
4.0 days, respectively. Plant to flower times differed largely because
of the length of time required for the rhizomes to sprout rather than for
the amount of time spent in inflorescence initiation and development.
Plant heights at flowering and inflorescence counts were not different
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within cultivars over the 10-week planting period. Degree days and
solar integrals will be presented for the 10 growing periods.
(74) Effect of Temperature on Axillary Bud
Formation and Polyamine Contents of Nonbranching
Chrysanthemum
Yeun Joo Huh*1, Seoung Youl Choi1, Hak Ki Shin,1 Chun Ho Pak2
1
National Horticultural Research Institute, Dept. of Floriculture, Top Dong 540-41, Suwon,
Kyungkido, 441-440, Korea; 2Korea Univ, Division of Bioindustrial Science
Nonbranching chrysanthemums [Dendranthema × grandiflorum
(Ramat.) Kitamura] are preferred because they require less labor
in disbudding. High temperature is responsible for this phenotype
of not having axillary buds or poor lateral shoot development. This
study attempted to find out the effect of temperature and identify
the involvement of endogenous polyamine contents in axillary bud
formation of nonbranching chrysanthemum cv. Iwanohakusen. Plants
were treated at 22, 26, 30, 34, and 38 °C for 9 hours midday for 2
months. Polyamine content [putrescine (Put), spermidine (Spd),
spermine (Spm)] was analyzed 1 month after treatment and axillary
buds were counted when the flowers opened. Results revealed that
viable axillary buds decreased remarkably at 30 and 34°C. It was also
found out that not only low temperature, but also the excessively high
temperature of 38 °C induced axillary bud formation. Exposure to 38
°C increased the Put contents and resulted in high Put/(Spd + Spm)
ratio as 22 °C, 26 °C. Temperature of 30, 34 °C lowered Put/(Spd +
Spm) ratio. Results further showed that not polyamine contents, but
polyamine ratio (Put/Spd + Spm) or transformation of Put to Spd and
Spm may be involved in the axillary bud formation in nonbranching
chrysanthemum.
(75) Quantifying the Vernalization Response of Dianthus
gratianopolitanus ‘Bath’s Pink’
Sonali Padhye*, Erik S. Runkle, Arthur C. Cameron
Michigan State University, Horticulture, East Lansing, MI, 48824
Two experiments were conducted to quantify the effect of vernalization
temperature and duration on flowering of Dianthus gratianopolitanus
‘Bath’s Pink’. In Expt. 1, plants were vernalized at 5 °C for 0, 3, 6,
9, 12, or 15 weeks and in Expt. 2, plants were vernalized at 0, 5 or
10 °C for 0, 2, 4, 6 or 8 weeks. After treatments, plants were forced
in a greenhouse at 20 °C. Node development, days to first visible
bud (DVB), days to first open flower (DFLW), number of buds and
height at FLW were recorded. In Expt. 1, 10% of nonvernalized plants
flowered and 100% of vernalized plants flowered. As vernalization
duration increased from 3 to 15 weeks, DTVB decreased from 24 to
13. Average DFLW were 114, 41, 34, 33, 33, and 28 for 0-, 3-, 6-, 9-,
12-, and 15-week treatments, respectively. In Expt. 2, 40% of plants
flowered without vernalization. Following 2 weeks of vernalization
at 0 °C, 80% of plants flowered and as the duration of vernalization
increased to ≥4 weeks, all plants flowered. Average DFLW decreased
from 38 to 28 following 2 or 4 weeks of vernalization at 0 °C. Longer
vernalization did not further reduce DFLW. All plants cooled at 5 °C
flowered and vernalization duration did not affect DFLW. Percent
flowering after vernalization at 10 °C for 2, 4, 6, and 8 weeks was
20%, 60%, 90%, and 100%, respectively, and average DFLW were 46,
45, 35, and 33, respectively. In conclusion, vernalization is required to
force D. ‘Bath’s Pink’. To achieve complete flowering, plants should be
vernalized at 5 °C for ≥2 weeks or at 0 °C for 4 weeks or at 10 °C for 8
weeks. Qualitative effects of vernalization such as node development
and number of buds and height at FLW will be discussed.
(76) Thermal Effects on Vegetative Growth and
Reproductive Behavior of Phalaenopsis Orchids
Yin-Tung Wang*
Texas A&M University System, Horticultural Sciences, Texas Agricultural Experiment
Station, Weslaco, TX, 78596
Since Phalaenopsis orchids are CAM plants, learning how they respond to night temperature warmer than the day would help regulate
their production. On 1 Apr. 2003, P. amabilis plants were subjected to
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(77) Tolerance to Rhizoctonia solani and Garden
Performance of Wax Begonia Cultivars
Carlos E. Bogran1, H. Brent Pemberton*2, Thomas Isakeit3,
William R. Roberson2
1
Texas A&M University, Entomology, College Station, TX, 77843; 2Texas A&M University,
Texas Agricultural Experiment Station, Overton, TX, 75684; 3Texas A&M University,
Plant Pathology and Microbiology, College Station, TX, 77843
A strain of Rhizoctonia solani was isolated from wax begonia (Begonia Semperflorens-Cultorum hybrids) plants in garden evaluation
trial plots. This strain was then used to test for disease tolerance in a
controlled environment experiment. Inoculated plants of 12 cultivars
were evaluated for disease development and the area under the disease
progress curve was calculated. No plants were disease free, but ‘Stara
White’, ‘Stara Pink’, and three colors from the Party series exhibited
greater disease tolerance than ‘Ambassador Coral’, ‘Ambassador Deep
Rose’, and two experimental varieties. ‘Stara White’, ‘Party Pink
Bronze Leaf’, and ‘Party White Bronze Leaf’ were more tolerant than
‘Cocktail Vodka’, an industry standard. When the same cultivars were
grown in field garden evaluation plots, ‘Cocktail Vodka’, four colors
from the Stara series, and three colors from the Party series exhibited
superior garden performance and flowering ratings to ‘Ambassador
Coral’ and an experimental ‘Rose’ cultivar. For most cultivars, garden
performance was correlated to disease tolerance. However, ‘Cocktail
Vodka’ exhibited good garden performance despite having a high level
of disease in the inoculation experiment, indicating that other factors
may be involved in determining garden performance.
(78) Establishment and Growth of Begonias in the
Landscape as Affected by Root Ball Condition at
Transplant
Sloane M. Scheiber*, Richard C. Beeson, Jr., Sudeep Vyapari
University of Florida, Environmental Horticulture, Mid Florida Research and Education
Center, Apopka, FL, 32703
Root ball slicing is often recommended for root-bound woody ornamentals to promote new root development during establishment in the
landscape. It is a common practice among gardeners, but not necessarily landscapers, to disrupt root-bound annuals during transplant.
However, little if any evidence exists for such practices. Therefore,
this study evaluated the effect of root ball condition of annual bedding
plants on landscape establishment and growth. Begonia semperflorens
were transplanted from 0.72-L (#1) containers into field plots in an
open-sided clear polyethylene covered shelter and managed with
Best Management Practices. Three root ball conditions were evaluated: non root-bound (6-week-old plants), root-bound (10-week-old
plants), and root-bound with the bottom 1 cm of the root ball removed.
Shoot and root dry masses and growth indices were collected weekly
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for 12 weeks and evaluated relative to root ball condition by linear
regression analysis. Nonroot-bound plants had significantly greater
biomass, growth indices, height, and root dry weights than the other
treatments tested. No significant differences were found between
root-bound and manipulated root-bound plants for any parameter
examined. The data indicate that the practice of disrupting root-bound
plants has no benefit on establishment or growth of annual bedding
plants in the landscape.
Poster Session 13—Plant Biotechnology 1
18 July 2005, 1:15–2:00 p.m.
Poster Hall–Ballroom E/F
POSTERS–MONDAY
day/night temperatures at 30/25, 25/30, 25/20, 20/25, 20/15, or 15/20
°C under 140 μmol·m-2·s-1 PPF. After 4 months, the total length of new
leaves was shorter as a result of fewer and shorter new leaves when
nights were cooler than the days and as the average daily temperature
declined. More spikes were produced at 25/20 and 20/25 °C than at
20/15 or 15/20 °C. In another experiment, P. amabilis plants were
moved to the above conditions on 12 Aug. Plants exposed to 30/25
or 25/30 °C had more leaf growth than at lower temperatures, but no
flowering. Plants that were exposed to 25/20 or 20/25 °C spiked in 2
weeks; but plants took 20 and 18 d to spike under 20/15 or 15/20 °C,
respectively. Again, as average daily temperature decreased, there
was less leaf growth. Cooler day than the night reduced vegetative
growth, regardless of temperature. Plants at 25/20 or 20/25 ºC had
higher flower count (12) than those at 20/15 or 15/20 °C (8). In a third
experiment, plants of a large-flowered Doritaenopsis hybrid spiked at
22–24 d when exposed to 25/20 or 20/25 °C, whereas 30-33 d were
needed to spike under 20/15 or 15/20 °C. In a fourth experiment, a
Doritaenopsis hybrid spiked after 22, 21, or 25 d under 25/25, 25/20,
or 20/20 °C. However, 37 d was required to spike under 20/15 °C.
These results suggest that the best temperature range for spiking these
orchids is 25 to 20 °C and a day/night temperature differential is not
needed for spiking when temperature is at or below 25 °C.
(262) Transgenic Tomato Lines Expressing Plant Defense
Genes Show Resistance to Early Blight Disease
Scott C. Schaefer, Ksenija Gasic, Schuyler S. Korban*
University of Illinois, Department of Natural Resources & Environmental Sciences,
Urbana, IL, 61801
Several plant defense genes, including an iris ribosomal-inactivating
protein (I-RIP) and a maize β-glucanase (M-GLU) as well as a small
antimicrobial peptide (5 kd) from Mirabilis jalapa (Mj-AMP) were
separately introduced into tomato (Lycopersicon esculentum) cv. Sweet
Chelsea using Agrobacterium tumefaciens-mediated transformation.
Transgenic lines carrying each of the transgenes were confirmed for
integration into the tomato genome using Southern blot hybridization. Transcription of I-RIP, M-GLU, and Mj-AMP genes in various
transgenic lines was determined using Northern blot analysis. Plants of
some transgenic lines were inoculated with a 2 × 104 to 3 × 104 conidial
spores/mL suspension of the fungal pathogen Alternaria solani, the
causal agent of tomato early blight disease. Several transgenic lines
carrying either a M-GLU or Mj-AMP transgene showed a higher level
of resistance to early blight than control (nontransgenic) plants. The
implications of this approach on developing disease resistance in
tomato will be discussed.
(263) Temperature Effects on Meristem Identity
Genes Controlling the Reproductive Development of
Cauliflower (Brassica oleracea var. botrytis) and Broccoli
(Brassica oleracea var. italica)
Denise V. Duclos*, Thomas N. Björkman
Cornell University, Department of Horticultural Sciences, NYSAES, Geneva, NY, 14456
Brassica oleracea species differ in the developmental stage of their
reproductive meristems at harvest. The stage that characterizes each
variety depends on its genetic makeup, environment and the interaction
between them. We tested a model of arrest in B. oleracea to determine
functional redundancy among the paralogous genes CAL, AP1a, AP1c,
FULa, FULb, FULc, and FULd; and to resolve the immediate effect
of temperature on gene expression in meristems whose developmental
fate is temperature regulated. By varying temperature during reproductive development, three stages of arrest were obtained: inflorescence
meristem (cauliflower), floral meristem (intermediate) and floral bud
(broccoli), the latter initiated by low temperature. Gene expression was
measured by quantitative real time PCR (qRT-PCR). The LFY/TFL1
ratio increased as the reproductive development advanced, mainly
due to decreased TFL1 expression; influenced by a dramatic increase
in AP1c toward floral bud formation. The expression patterns of the
FUL paralogs indicate different roles in reproductive development.
FULa was more abundant in the floral primordia, while FULb, FULc,
and FULd were associated with earlier arrest at the inflorescence
meristem stage. The high expression of FULc and FULd at all stages
of arrest differs from their homolog in Arabidopsis. High temperature
reduced AP1 and LFY expression but the meristem did not revert from
reproductive to vegetative. Floral bud formation in plants recessive
for AP1a and CAL reaffirm that functional redundancy among some
of these genes can complement the mutations. Varying temperature
alone, at a fixed developmental stage, caused little variation in the
expression of genes studied, causing small significant differences in
TFL1 and AP1c.
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(264) In Vitro Pollen Germination of Wild Type and
Transgenic ‘Galia’ Male Parental Line Melon [Cucumis
melo (L.) var. reticulatus Ser.]
Hector G. Nunez-Palenius*, Daniel J. Cantliffe, Harry J. Klee,
Don J. Huber
University of Florida, Horticultural Sciences Department, Gainesville, FL, 32611-0690
Pollen germination timing has a paramount role in fertilization of
a flower. Rapid germination and outgrowth of a pollen tube that
penetrates the stigma is required. Physical and biological factors can
affect pollen germination timing. The objective of this study was to
determine if ACC oxidase antisense gene expression could influence
in vitro pollen germination and in vitro pollen tube length growth. A
transgenic (ACC oxidase antisense) ‘Galia’ male parental line had a
reduced fruit set compared to its wild type. Likewise, embryo abortion
and empty seeds after self-pollination in a ‘Galia’ male parental line
were observed. Wild type and transgenic ‘Galia’ male parental line
melon plants were grown in a greenhouse according to the practices
of Rodriguez (2003). Male flowers were collected from these plants
between 10 to 12 am; pollen was obtained by dipping the anther
in germination medium (10.25% sucrose, 0.031% calcium nitrate,
0.015% boric acid, 0.0075% KNO3, and 0.016% MgSO4) at 25 °C
and analyzed immediately, either for total percentage of germination
after 5 minutes of incubation or to measure pollen tube growth rate
every 5 minutes during 1 hour. Each flower provided an average of
250 pollen grains. Assays were conducted by using the “Hanging Drop
Method” (Okay and Ayfer, 1994). Percentage of pollen germination
in WT ‘Galia’ male parental line was greater than the transgenic line.
Likewise, in vitro pollen tube growth in wild type ‘Galia’ melon was
greater than pollen from the transgenic line. Possibly the ACC oxidase
antisense gene expression in ‘Galia’ male parental line may have had
an influence on the reduced fruit set observed.
(265) HSP101 in the Model Strawberry Fragaria vesca
Janet Slovin*
USDA/ARS, Fruit Laboratory, BARC-W Bldg 010A, Beltsville, MD, 20705
Our lab has initiated a project to determine if specific proteins expressed
by strawberry function as part of the thermotolerance system. We
have developed tools for investigating the role of heat shock proteins
(HSPs) and other gene products in strawberry thermotolerance. These
tools include an inbred diploid testing system, EST sequence data,
and molecular markers for heat tolerance. We developed an inbred
line, 5AF7, of the diploid strawberry Fragaria vesca for testing gene
function because the diploid genome is small (164Mbp), the life cycle
of the plant is short (about 4 months), the plant size is small (a plant
will produce fruit in a 4-inch pot), some genetic work is already done,
F. vesca is transformable with Agrobacterium tumefaciens, and results
should be transferable to the commercial octoploid varieties. A cDNA
library was constructed in the pCMVsport 6.1 vector using combined
RNA from batches of aseptically grown F. vesca seedlings treated to
various elevated temperature regimes. Over 1500 EST sequences from
the library have been deposited in GenBank and are available annotated
at the ESTAP Fragaria database (http://staff.vbi.vt.edu/estap/index.
shtml). HSP101 affects thermotolerance in Arabidopsis (Queitsch et al.,
2000, Plant Cell 12:479). A PCR fragment for HSP101 was generated
from F. vesca with degenerate primers, and used to obtain a full-length
cDNA clone from the library. Primers spanning an intron were designed
for RTPCR from the sequence of the cDNA. Semi-quantitative RTPCR
indicates that HSP101 is expressed constitutively in young leaves at
25 °C and is not induced at moderately higher temperatures (32 °C)
even after 5 hours. Induction occurs within 1 hour at 37 °C.
(266) Gene Discovery in Octoploid Strawberry
Philip J. Stewart*, Dawn H. Bies, Kevin M. Folta
University of Florida, Horticultural Sciences, Gainesville, FL, 32611
Fragaria ×ananassa, the cultivated octoploid strawberry, is an intensively cultivated fruit crop in which relatively small variations in
disease susceptibility and flowering habit can have significant economic impacts. In order to facilitate future studies of the molecular
1016
final6_20July HS.indb 1016
mechansisms governing these characters, we have initiated studies
to identify and sequence the strawberry homologs of a number of
important genes known to be critical to pathogenesis response and
photoperiodism in model systems such as arabidopsis, rice, and
tomato. Using the primary Florida cultivar Strawberry Festival, we
have employed a variety of techniques to identify such genes, including EST sequencing of a salicylate-induced cDNA library, PCR with
degenerate primers, and colony hybridization. Possible homologs of
the targeted genes and their relationships to similar genes in other
species are presented. These results will form the basis of future
studies of gene expression and evolutionary relationships among the
Rosaceae and other species.
(267) A Rapid Transformation System for Octoploid
Strawberry
Leighan Howard, Philip Stewart*, Amit Dhingra, Craig Chandler,
Kevin Folta*
University of Florida, Horticultural Sciences Department, Gainesville, FL, 32611
Cultivated strawberry (Fragaria ×ananassa) is a valuable crop, yet has
benefitted little from recent advances in biotechnology and genomics.
A high-throughput system for transformation and regeneration would
hasten elucidation of gene function for strawberry and possibly the
Rosaceae in general. In this report, a protocol for high-frequency
octoploid strawberry transformation and regeneration is presented.
The protocol uses leaf, petiole, and stolon as explants from a newly
selected genotype, ‘Laboratory Festival #9’. This genotype was selected
from progeny of a ‘Strawberry Festival’ self-cross exclusively for its
rapid regeneration and robust growth in culture. Direct organogenesis
has been achieved from the leaf or from prolific callus with multiple
shoots being visible in as few as 14 days. Over 100 viable regenerants
may be obtained from a single leaf explant of about 3-cm2 size. This
laboratory-friendly genotype allows high-throughput, statistically
relevant, studies of gene function in the octoploid strawberry genetic
background as well as generation of large transgenic populations.
(268) Nonspecific Fusarium Wilt Resistance in
Watermelon Using Copper Inducible IPT Gene
Fahrettin Goktepe*, Harrison Hughes
Colorado State University, Dept. of Horticulture & Landscape Architecture, Fort Collins, CO 80525
‘Crimson Sweet’ watermelon was transformed with a copper inducible ipt gene. Clonally propagated transformed and non-transformed
plants were sprayed with three different concentrations (0, 50, 100
mM) of CuSO4 at the 2–3 leaf stage twice in a 24-hour period prior to
their inoculation with fusarium wilt organisms. Plants were inoculated
via root dip with two different isolates of Fusarium oxysporum sp.
niveum Race 2. The pathogenic strains of Fusarium oxysporum sp.
niveum Race 2, Fl 99-1, and Calg 15-19, were cultured on PDA solid
medium and then transferred to a sterile flask filled with 50 mL of
potato dextrose broth (PDB) liquid medium. These flasks were placed
on a shaker at 100 rpm for 4–5 days before the inoculation date and
the final concentration of 106 spores/mL was adjusted for inoculation.
Roots of the experimental units were gently washed and were then
infected by dipping them in to the beaker containing the isolates for
1 min. Inoculated plants were transferred to planting trays and maintained under growth chamber conditions. Plants then were watered as
needed. Fusarium wilt symptoms initially appeared approximately 7–10
days after the infection. The Cu-ipt transformants exhibited a clear
and significant resistance over non-transformed plants. The severity
of disease development was relatively higher in the control Cu-ipt
and non-transformed plants when compared to the plants treated with
CuSO4. The control Cu-ipt plants were comparatively healthier than
the control non-transformed plants. Infected plants were removed
from soil 2 weeks after inoculation, washed and the stems were cut
vertically for rating of browning of the vascular system.
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(269) Taxonomic Relationship of Korean Native Aster,
Based on Internal Transcribed Spacer (ITS) Sequences of
Nuclear Ribosomal DNA
(353) University of California Water Quality Program for
Floriculture and Nursery Growers in Ventura and Los
Angeles Counties
Su-Young Hong*1, Kwang-Soo Cho1, Ki-Oug Yoo2, Jong-Taek Suh1,
Dong-Lim Yoo1
Julie Newman*1, Kristine Gilbert1, Ben Faber1, Donald Merhaut2,
Laosheng Wu3, Jay Gan3, Richard Evans4
1
1
National Institute of Highland Agriculture, Horticulture, Heonggae, Doam, Pyeongchang,
Gangwon Province, 232-955, Rep. South Korea; 2Gangwon National University, Department
of Biology, Chuncheon, Gangwon Province, 200-701, Rep. South Korea
Poster Session 14—Water Utilization in Horticulture
Nursery growers must implement “Best Management Practices” (BMPs)
to mitigate runoff and leaching of pollutants. However, there is little data
on the effectiveness of BMPs, and further research is needed. Growers
require training to minimize runoff and capital to comply with evolving
regulations. We collected irrigation efficiency data at 26 nursery sites
using catch cans. Uniformity value was calculated as: DU = 100 ×
(Average of the “Low Quarter”/Average of All Measurements). Results
showed that one-third of the nurseries had irrigation uniformities below
67%, and only one nursery exceeded 82%. Continuous flow monitoring
at 10-minute intervals was conducted at three nursery sites to determine
daily and monthly variation. One hundred samples of the runoff were
taken four times at each nursery and analyzed for nitrate, chloride, and
sulfate. We developed a 29-page checklist of BMPs to reduce runoff,
which we used to survey 53 growers in Ventura County. After completing the survey, 20 growers applied for funds from a 1.2 million dollar
cost-share program that we initiated. This program provides funds to
implement improved technologies to reduce runoff and/or conserve
water; funds were awarded to 18 nurseries. We are collecting monitoring
data from each cooperating nursery implementing improvements. These
data measure the number of BMPs used by growers, provide a current
“snapshot” of the industry, and document the effectiveness of future BMP
implementation. We offer on-farm consulting, and conducted eight water
quality/irrigation educational programs—four in Spanish. We elevated
grower awareness concerning regulations and options for reducing
runoff, and the data will be useful in evaluating future improvements.
19 July 2005, 12:00–12:45 p.m. Poster Hall–Ballroom E/F
(354) A Novel Automated System for Irrigation and
Simulating Drought Stress in Potted Plants
(352) Genetic and Environmental Effects Related to
Water Use Efficiency in Peach
Krishna S. Nemali*, Marc W. van Iersel
D. Michael Glenn*1, Ralph Scorza1, William R. Okie2
1
Appalachian Fruit Research Station, USDA, Kearneysville, WV, 25430; 2Fruit and Tree
Nut Research Laboratory, USDA-ARS, Byron, GA, 31008-1008
Two unpruned willow leaf and two unpruned standard leaf peach
[Prunus persica (L.) Batsch.] selections were evaluated for physiological components related to water use efficiency (WUE). The purpose
of the study was to assess the value of willow leaf phenotypes to
improve water use efficiency in peach and separate the environmental
from the genetic components. The willow leaf characteristic itself did
not confer improved water use efficiency. Light interception was a
key determinant of WUE in these genotypes and the relationship of
WUE with intercepted photosynthetically active radiation (PAR) by
the entire canopy indicated a significant negative correlation. Internal
shading of the tree by excessive leaf area reduced WUE and canopies
that intercept more than 60% of the PAR have reduced WUE. While
WUE is improved by reducing the amount of PAR interception of the
canopy, productivity is reduced. Neither of the willow leaf genotypes
had a significant correlation of WUE with yield (leaf and fruit weight);
however, the standard leaf type cultivars, ‘Bounty’ and ‘Redhaven’, had
significantly different regressions that indicate greater productivity in
‘Bounty’ for a given level of WUE. ‘Redhaven’ was the least productive
cultivar; ‘Bounty’ was the most productive, and the two willow leaf
genotypes were intermediate in the relationship of intercepted PAR
with yield. Therefore, genetic differences in peach growth types can
be selected for both increased WUE as well as increased productivity. Future work in peach breeding to improve WUE and productivity must take into consideration light interception, productivity, and
WUE in an integrated manner to make progress in the efficient use
of water and light.
University of Georgia, Horticulture Department, 1111 Miller Plant Sciences Building,
Athens, GA, 30602
We have developed a completely automated irrigation system that measures and maintains substrate volumetric water content (θ) at a target
level for any length of time. Advantages of this system include complete
automation of irrigation and simulation of precise levels of drought stress
for potted plants. This system uses ECH2O moisture sensors interfaced
with a CR10X datalogger and solenoid valves connected to the datalogger by a SDM CD16 AC/DC controller. The datalogger measures the
θ of the substrate hourly. When the θ of the substrate drops below the
set point, the datalogger opens the solenoid valves, which results in
irrigation. Substrate θ is maintained at a constant level as the datalogger is programmed to increase θ by 2% to 3% during each irrigation.
When the system was validated for its accuracy, we determined that the
θ measured in the substrate within the range of 0.15 to 0.35 m3·m-3 was
close (2% to 3%) to the θ determined by the conventional volumetric
analysis. The daily average θ maintained in the substrate was slightly
higher (within 3%) than the target level. Using this system, we were able
to maintain four distinct levels of substrate θ for a prolonged period (40
days), regardless of differences in plant size and environmental conditions. Significant increases in number of irrigations, total water-use, and
transpiration rate of impatiens, salvia, vinca, and petunia were noticed
with increasing target θ of the substrate. For all species, highest and
lowest water-use efficiency (WUE) were seen at 0.09 and 0.32 m3·m-3,
respectively, while WUE was not different between 0.15 and 0.22 m3·m-3.
(355) Evaluation of Three Models for Estimated Potential
Evapotranspiration under Sonoran Desert Conditions
Fabián Robles-Contreras, Raul Leonel Grijalva-Contreras*, Manuel de Jesus Valenzuela-Ruiz, Rubén Macias-Duarte
1
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POSTERS–TUESDAY
There are 25 species of aster in Korea. There is a controversy about
the taxonomical classification of Aster. The genus Aster was classified
into four genera, Aster, Gymnaster, Kalimeris, and Heteropappus, by
morphological characters. In order to clarify the phylogenetic position
of aster, the nucleotide sequence of the nuclear ribosomal DNA internal
transcribed spacer (ITS) region was compared among 11 taxa in Korean
native aster. The size of ITS1 and ITS2 ranged from 283 to 286 bp and
from 251 to 257 bp, respectively. The size of 5.8S region was 164 bp
in 11 taxa. The total length of ITS1, 5.8S and ITS2, A. tripolium was
shown to be the shortest length, 701 bp; and A. scaber was shown to
be the longest length, 706 bp. The G+C content of ITS1 ranged from
47.9% to 51.2% and ITS2 ranged from 52.2% to 55.1%. The range of
each taxon was narrow. The total length of the character matrix was 708
characters. Among them, total indel showed 9; in the ITS1 region indel
showed 6 it was 67%; and in the ITS2 region, indel showed 3. Most
of the indels showed deletion or insertion of only one base pair, but
in A. spathulifolius deleted two base pairs and in A. tripolium deleted
five base pairs. But in A. yomena, A. hayatae, A. koraiensis, and A.
hispidus, the indel was not detected. Phylogenetic trees did not even
make a difference inter-genus, but A. yomena and A. koraiensis called
genus Kalimeris and genus Gymnaster, respectively; these constituted
a clade. A. hispidus called genus Heteropappus was placed as a sister
group to the clade of A. ageratoides and A. glehni.
University of California, UC Cooperative Extension, Ventura Co., Ventura, CA, 930035401; 2University of California, Riverside, Botany and Plant Sciences, Riverside, CA;
3
University of California, Riverside, Soils & Environmental Sciences; 4University of
California, Davis, Environmental Horticulture, Davis, CA, 95616
INIFAP-Caborca, Agroclimatology, Caborca, Sonora, 83600, México; 2INIFAP-Caborca,
1017
6/20/05 5:01:11 PM
Protected Horticulture; 3INIFAP-Caborca, Viticulture; 4INIFAP-Caborca, Soli & Horticultural
The main crops in Caborca, Sonora, Mexico, in the Sonoran Desert,
are grapes, asparagus, olive, and vegetables, such as melons and green
beans. The growers in this area normally do not use methods to calculate
water requirements of the crops, although in a desert region water use
management needs to be as efficient as possible. A reason for using
some of the models is the need to fit water requirements to regional
conditions, or some stress could be caused in the crops. Recently, studies have been made in northwestern Mexico that indicate it is feasible
to adapt the use of the Makkink model. Three models for estimated
potential evapotranspiration (Eto) were evaluated: Penman-Monteith,
Hargreaves, and Makkink, and were compared with the Class A pan
method (control). Measured variables were the correlation coefficient
(R2) between the models and the control; and the daily average difference between the models and the control. The results indicate that
a low R2 exists between the three evaluated models and the control
(0.55, 0.67, and 0.54 for Hargreaves, Penman-Monteith, and Makkink,
respectively). The average difference of the daily Eto in the course of 75
days of evaluation was of 0.62, 0.5, and 0.81 mm/day for Hargreaves,
Penman-Monteith, and Makkink, respectively. This represents almost
6–10 cm less of potential evapotranspiration with the models, for a
cycle crop of 120–130 days.
(356) Adaptation of Makkink Model to Obtain Potential
Evapotranspiration under Sonoran Desert Conditions
Fabián Robles-Contreras1, Raul Leonel Grijalva-Contreras*1,
Manuel de Jesus Valenzuela-Ruiz2, Rubén Macias-Duarte3
1
INIFAP-Caborca, Agroclimatology, Caborca, Sonora, 83600, México; 2IINIFAP-Caborca,
Viticulture; 3INIFAP-Caborca, Soli & Horticultural
Water is a very limited resource in the Sonoran Desert region of Caborca,
Sonora, Mexico. For an efficient use of irrigation water, a method
of calculating water requirements of the crops is needed. Potential
evapotranspiration (Eto) value obtained with the Penman-Monteith
model from a regional weather station was not dependable, since
some parameters, such as sensible heat flux in the soil, are estimated
from a fixed rate with net radiation (Rn), also an estimated value. The
weather station did not have a sensor for heat flux in its network. Studies in northwestern Mexico have indicated that it is feasible to adapt
the use of the Makkink model, because a single measurement of solar
radiation and temperature would be required. We compared the daily
Makkink Eto against the Class A pan method (control) Eto during 75
days and found a value of 0.81 mm/day less with the Makkink model.
To fit the Makkink model to regional conditions, we ran the Makkink
model varying the value of C constant (from 0.5 to 0.95), and found
that a value of C = 0.87 substituted for C = 0.65 (original value) has
an daily average difference of 0.09 mm/day less with respect to the
control. This could be because there are few clouds in the region, and
a greater proportion of global radiation arrives at the surface from the
earth or the crops in form of net radiation.
Poster Session 15—Vegetable Breeding 1
19 July 2005, 12:00–12:45 p.m. Poster Hall–Ballroom E/F
(245) ‘WhipperSnapper’, a Dual-purpose Southernpea for
the Production of Both Snaps and Fresh-shell Peas
Richard L. Fery*1, Blair Buckley2, Dyremple B. Marsh3
1
USDA-ARS, U.S. Vegetable Laboratory, Charleston, SC, 29414-5334; 2LSU AgCenter,
Red River Research Station, Bossier City, LA, 71113; 3Delaware State University, 127
Washington Extension Center, Dover, DE, 19901
Home gardeners and farmers in the southern United States have traditionally grown southernpeas to produce both fresh-shell peas and
immature, fresh pods, or snaps. American growers do not presently
have access to a single variety that is ideally suited for both uses. In
1988, a plant breeding effort was initiated to incorporate genes conditioning superior yield and seed characteristics of Asian “vegetable
cowpeas” into American snap-type southernpeas. This effort resulted
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final6_20July HS.indb 1018
in the development of ‘WhipperSnapper’, which is suited for use as
a dual-purpose variety that can be used to produce both snaps and
fresh-shell peas. Typical ready-to-harvest ‘WhipperSnapper’ snaps
are green colored, 6.4 mm in diameter, 7.6 mm in height, and 24 cm
long. Typical mature-green pods suitable for fresh-shell harvest exhibit an attractive yellow color, are 25 cm long, and contain 14 peas.
Fresh peas are cream-colored, kidney-shaped, and weigh 24.5 g per
100 peas. Dry pods exhibit a light straw color, and the dry peas have
a smooth seedcoat. The total ‘WhipperSnapper’ yield of snaps can
be as much as 62% greater than the total snap yield of the snap-type
variety ‘Bettersnap’; pea yield can be as much as 69% greater. The
quality of ‘WhipperSnapper’ seed is excellent and much superior to
that of ‘Bettersnap’. ‘WhipperSnapper’ can be used by home gardeners and market gardeners to produce abundant quantities of snaps and
fresh-shell peas during seasons too hot for successful culture of such
table legumes as snap beans. ‘WhipperSnapper’ also has the potential
for use as a mechanically harvested source of snaps for use by food
processors in mixed packs of peas and snaps.
(246) Crude Lipid Content and Its Relationship to
Carotenoid and Tocopherol Concentration in Carrot
(Daucus carota)
Jennifer L. Baeten*, Thomas C. Koch, Irwin L. Goldman
University of Wisconsin-Madison, Horticulture, Madison, WI, 53706
Carrot has been bred for increased levels of pro-vitamin E α-tocopherol.
This vitamin is lipid soluble. Carrot root has been shown to have measurable levels of lipid, but it is not certain if the lipid level is correlated to
α-tocopherol levels. The HPLC method is needed to quantify levels of
α-tocopherol. Measuring lipids may be less time consuming in a breeding program. We developed a method for extracting lipids from carrot
tissue based on the Soxhlet extraction method. The Soxhlet extraction
uses a non-polar ether solvent to pull lipids out of freeze-dried tissue.
A collection of carrot accessions ranging in α-tocopherol concentration 0.04–0.18 ppm and carotenoid concentration 10.63–1673.76 ppm
were used in this investigation. Root tissue was freeze-dried and lipid
levels were measured in an experiment with two replications. The mean
lipid level of root tissue was 0.05 g fat/g tissue. The range was 0–1.1 g
fat/g tissue. Phenotypic correlations were performed among lipid, αtocopherol, and β-carotene concentrations in these samples. Twenty-four
samples were tested for lipid levels (12 high and 12 low). From these
results, percent lipid of the root was determined. Correlations were made
between the lipid data and α-tocopherol data of the given samples.
(247) Genetic and Environmental Effects on Glucosinolate
Content in Chinese Cabbage
Ji Yeon Kang1, Khalid E. Ibrahim*1, Doo Hwan Kim2,
Wha-Jeung Kang3, John A. Juvik1
1
University of Illinois, Natural Resources and Environmental Sciences, Urbana, IL, 61801;
Konkuk University, Horticultural Science, Seoul, 143-701, Korea; 3National Horticultural
Research Institute, Vegetable Research Division, Suwon, 440-706, Korea
2
Gluconasturtiin is a glucosinolate (GS) present in Chinese cabbage and
its breakdown product, phenelethyl isothiocyanate (PEITC), inhibits
phase I enzyme activation of endogenous carcinogenic compounds
and enhances phase II enzyme detoxication, reducing cancer risk and
promoting health in humans. This study was conducted to evaluate
the interaction between the genotype and the environment to influence GSs in Chinese cabbage. Twenty-five accessions were grown
in three environments and tissue quantified for GS levels by HPLC.
While gluconasturtiin was observed to be the most abundant GS form,
3-indolylmethyl GS (glucobrassicin) and 1-methoxy-3-indolylmethylGS (neoglucobrassicin) were also found. Significant differences were
observed among tissues, genotypes and environments in GS concentration and composition. Gluconasturtiin ranged from 0.56 μmol·g-1
DW in leaf tissue of Hau No. 2 to 11.89 μmol·g-1 DW in Chilsung.
There were dramatic differences among different tissues of the same
genotype with young leaf and root tissues having significantly higher
concentrations of gluconasturtiin than other tissues. Gluconasturtiin
in Sandong No. 5 ranged from 1.69 μmol·g-1 DW in mature leaves to
18.69 μmol·g-1 DW in root tissue. GS content of the same genotypes
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in three different environments indicated that plants grown in the
greenhouse had higher GS content compared to field grown plants.
Results of this study indicate that genotypic variation and the growing
environment have substantial effects on GS content in Chinese cabbage.
This investigation provides important information for future genetic
and molecular studies and has identified Chinese cabbage genotypes
that offer superior health benefits to consumers.
(248) New Four Genes Related to Seed Characteristics,
Flower Appearance, and Red Color
Zhoo-Hyeon Kim*
Gyeongsang National University, Dept. of Horticulture, 900 Gazwa-dong, Jinju, Gyeongsangnam-Do, 660-701, South Korea
(249) Evaluation of Five Genotypes of Tomato
(Lycopersicon esculentum Mill.) in Greenhouse
Marcelino Bazan Tene*, Juan Manuel González Gonzalez,
Francisco Radillo Juarez, Pablo Enrique Ramírez Castillo
Universidad de Colima, Facultad de Ciencias Biológicas y Agropecuarias, Km 40 Autopista
Colima–Manzanillo, Tecomán, Colima, 28100, México
The tomato (Lycopersicon esculentum Mill.), is native to South America.
It occupies the second place in worldwide vegetable consumption. Because of this, the evaluation of tomato varieties for the fresh consumption is important. The Mexican production is 1,908,607 tons of fresh
product (SAGARPA, 2004). In the state of Colima, production has a
mean efficiency of 18.13 t·ha-1 (INEGI, 2000). The following genotypes
were evaluated ‘Peralta’, ‘Montijo’, Pavia’, ‘Grande River’, and ‘Yaqui’
(control). A randomized experimental block was used, with five treatments and four repetitions. The obtained results indicate that ‘Yaqui’
(control) had the better yield of fresh fruit, with 37.5 t·ha-1, followed
by ‘Peralta’ (27.2t·ha-1), and ‘Montijo’ (12.6 t·ha-1), respectively. The
height of plant in ‘Yaqui’ was 68.8 cm and 60.26 cm in ‘Pavia’. In the
days to flowering, after showing a homogenous behavior, pronouncing
itself up to 27 days after the transplant; whereas the variety ‘Grande
River’ was pronounced up to 40 days. With respect to the number
of total fruits by plant, a highly significant difference was observed.
‘Yaqui’ produced 91 fruits, with ‘Pavia’ and ‘Peralta’ producing 50
and 37 fruits per plant, respectively. In conclusion, ‘Yaqui’ was the
genotype with greater yield and vigor.
(250) ‘Elegance’ and Ark 98-348: Two New Southernpea
Varieties for the Mid-South
Teddy E. Morelock*1, D.R. Motes2, L.W. Martin2, S.E. Eaton2
1
University of Arkansas, Horticulture, Fayetteville, AR, 72701; 2University of Arkansas,
Vegetable Substation, Kibler, AR, 7295
Southernpeas, Vigna unguiculata, are a popular vegetable in the south-
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(251) ‘Evergreen’ and F415: Two New Spinach Varieties
for the Mid-South
Teddy E. Morelock*1, J.C. Correll2, Frank J. Dainello3, D.R. Motes4
1
University of Arkansas, Horticulture, Fayetteville, AR, 72701; 2University of Arkansas,
Plant Pathology, Fayetteville, AR, 72701; 3Texas A&M University, Horticulture, College
Station, TX, 77843; 4University of Arkansas, Vegetable Substation, Kibler, AR, 72956
Spinach, Spinacia oleracea, is a highly nutritious vegetable that is
increasing in popularity more rapidly than any other salad crop. In
the eastern United States spinach production is severely impacted by
white rust, Albugo occidentalis. For many years, the University of
Arkansas has bred spinach to cope with this endemic problem. While
fungicides can provide a degree of control, the combination of genetic
resistance and fungicides is the most effective method to insure production stability. ‘Evergreen’ and F415 are the latest developments of
this breeding program. ‘Evergreen’, widely tested as Ark 88-212, is
a slow growing, dark green, semi-savoy spinach that exhibits a good
level of white rust resistance. It is not long-standing and should not
be used for spring production in Arkansas and Oklahoma. It has been
widely tested in Arkansas and Texas. F415, widely tested as Ark 91415, is an upright, dark green, flat leaf spinach that has a good level
of white rust resistance. It is is well suited to the Arkansas, Oklahoma
and Texas production area and, because of its better color and more
upright growth habit, it should replace Ark F380.
POSTERS–TUESDAY
New four traits not yet reported were founded. One mutant plant was
from a population of 81-1251-D-20M treated with EMS (ethylmethane
sulfonate), which had tubular petals. This tubular petal plant had normal
pollens in anthers, but could almost not produce its seeds without artificial
pollination. It was controlled by one single recessive gene. One new
spontaneous dwarf mutant line, R3-10, which bore seedcoatless-like
seeds with short pappus, was crossed with normal breeding lines GL5
and 87-25M-2M. From F2 and F3 results, it was found that the two
traits (seedcoatless-like and short pappus) were governed by each one
single recessive gene. A stem lettuce type cultivar, ‘Baimach’, seemed
to be almost green , but was really tinged red, which was extremely
suppressed in red color expression. Its tinged red color could not be
seen, except on only very limited base parts of the stem and dorsal
petal. In two F2 population experiments of the crosses of ‘Baimach’
with ‘Oakleaf’ and 98-43-3, it was found that the suppression of red
color expression in ‘Baimach’ was caused by a single recessive gene.
It looked different from that of gene “v” ( vanishing) by Lindqvist,
because the red color of plants with “v” gene of Lindqvist were typically tinged and could be identified easily at a young plant stage, but
not that of ‘Baimach’. I designated these new four genes as Tu-tu (Tu
= normal, tu = tubular petal), Pp-pp (Pp = normal, pp = short pappus),
Scl-scl (Scl = normal, scl = seedcoatless-like), and In-in (In = normal,
in = inhibiting red color expression extremely).
eastern United States. Southernpeas (cowpeas) are widely known by
the many different horticultural types, i.e., blackeye, pinkeye, purple
hull, cream, cowder, etc. ‘Elegance’ was widely tested under the
designation Ark 96-918. It was entered in the Regional Southernpea
Cooperative Trials from 1997–2002, where it performed well. It is
a root-knot nematode resistant cream that exhibits an upright bush
habit with concentrated pod set and good yield potential. The seed are
medium size and produce a high quality canned product. ‘Elegance’
is unique in the fact that it is a purple hull cream with the pods turning
from dark green to purple when the seed reach the green mature stage.
The second release, Ark 98-348, is a selection out of ‘Chinese Red’ that
is less viney and has a more concentrated pod set and maturity than
the ‘Chinese Red’ types that are commercially grown. It was tested
in the observational Regional Southernpea Cooperative Trials from
2000–02. In trials at the University of Arkansas Vegetable Substation,
it outyielded industry standard ‘Chinese Red’ types Ark 93-640 and
93-641, by 30%.
(252) Correlation of Pungency, Thiosulfinates, Antiplatelet
Activity, and Total Soluble Solids in Two Garlic Families
Pablo Cavagnaro1, Douglas Senalik2, Claudio Galmarini1,
Philipp Simon*3
1
Universidad Nacional de Cuyo and EEA INTA La Consulta-Mendoza, Facultad de Ciencias
Agrarias, Mendoza, 5519, Argentina; 2USDA-ARS Vegetable Crops Research Unit and
Department of Horticulture, University of Wisconsin-Madison, Madison, WI, 53706
Allium plants possess organosulfur compounds and carbohydrates that
provide unique flavor and health-enhancing properties. In previous studies of onion F3 families, significant phenotypic and genetic correlations
have been reported between pungency, in vitro antiplatelet activity
(IVAA), and soluble solids content (SSC); although in other studies
SSC and pungency have not always been correlated. In this study we
analyzed SSC, pungency, garlic-induced in vitro antiplatelet activity
and the content of three predominant thiosulfinates in bulbs from two
garlic families obtained from unrelated self-pollinated plants. A strong
positive correlation was observed between pungency and IVAA for
both sample sets, indicating that it will be difficult to develop garlic
populations with low pungency and high IVAA. Allicin was the most
abundant thiosulfinate and its content was positively correlated with
pungency and IVAA (r = 0.70 and 0.74, respectively). The thiosulfinates
AllS(O)SPropenyl and AllS(O)SMe were also positively correlated with
pungency and IVAA. When compared with IVAA, AllS(O)SMe had
higher r values than AllS(O)SPropenyl (0.88 and 0.50, respectively).
These differences could reflect differential platelet anti-aggregatory
properties of different thiosulfinates. SSC was not correlated with IVAA,
pungency, or thiosulfinates content, suggesting that soluble solids in
garlic can be independently selected.
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6/20/05 5:01:14 PM
(253) TAM ‘Dulcito’ and ‘Tropic Bell’—Two New Sweet
Peppers with Enhanced Beneficial Phytochemical Levels
Kevin M. Crosby1, Daniel I. Leskovar*2, Kil Sun Yoo3
1
Texas A&M University, Horticultural Sciences, Texas Agricultural Experiment Station,
Weslaco, TX, 78596; 2Texas A&M University, Horticultural Sciences, Texas Agricultural
Experiment Station, Uvalde, TX, 78801; 3Texas A&M University, Horticultural Sciences,
Vegetable and Fruit Improvement Center, College Station, TX, 77845
At the Vegetable and Fruit Improvement Center, plant breeding has
produced pepper lines with enhanced beneficial phytochemical levels.
TAM ‘Dulcito’ is a new jalapeño cultivar with no detectable levels of
capsaicin, but increased levels of lutein. In greenhouse cultivation, it
contained 122 ppm of this important human health-related compound,
which aids in prevention of macular degeneration. This is a significant
improvement over popular cultivars, such as ‘Grande’, which contained
25 ppm or less. In addition to improved lutein levels, ‘Dulcito’ also
possesses resistance to three important potyviruses: TEV, PepMoV, and
PVY. In field trials at Weslaco, Texas, ‘Dulcito’ outyielded both TAM
‘Mild Jalapeño 2’, and ‘Mitla’. This new cultivar produces a concentrated set of large, thick-fleshed fruit with few cuticular cracks. Because
of its lack of pungency, it should be useful for the processing industry.
TAM ‘Tropic Bell’ is a medium-sized, blocky bell with enhanced levels
of both ascorbic acid and lutein compared to other cultivars. Grown
under greenhouse conditions, it contained 100 ppm lutein compared
to 6 ppm in ‘Jupiter’. It also contained 660 ppm ascorbic acid at the
green stage, compared to less than 100 ppm for three commercial bell
cultivars tested. ‘Tropic Bell’ produced yields equal to both ‘Valiant’
and ‘Summer Sweet’ commercial hybrids at Weslaco. Fruit of ‘Tropic
Bell’ were slightly smaller than the hybrid cultivars. TAM ‘Tropic Bell’
possesses resistance to the same three potyviruses as ‘Dulcito’ and
demonstrated excellent tolerance to Phytophthora capsici in a controlled
inoculation. These two new cultivars will be useful for production in
locations with high potyvirus pressure or as specialty market items for
health-conscious consumers.
Poster Session 16—Plant Biotechnology 2
19 July 2005, 12:00–12:45 p.m.
Poster Hall–Ballroom E/F
(270) Single-nucleotide-polymorphism Isolation in Fruitingmei (Prunus mume Sieb. et Zucc.) from AFLP Fragments
Jinggui Fang, Pachanoor S. Devanand, ChihCheng T. Chao*
1
University of California-Riverside, Department of Botany and Plant Sciences, Riverside,
CA, 92521-0124
Single-nucleotide-polymorphism (SNP) is the most abundant genetic
variation among individuals within a species. SNPs can be used as markers
for gene discovery and for assessment of biodiversity. We established
a practical strategy for discovering candidate SNPs in fruiting-mei
(Prunus mume Sieb. et Zucc.), a non-model tree fruit, from amplifiedfragment-length-polymorphism (AFLP) fragments. Eighty-one of the
150 chosen bands from 10 cultivars of fruiting-mei were successfully
re-amplified and 67 of these re-amplified PCR products yielded 13
groups of reliable sequences. The sequencing results from both directions of 23 randomly selected PCR products using the corresponding
selective primers showed that all the purified fragments from the gels
were EcoR I-EcoR I fragments. The sequence alignment of 13 groups of
sequence yielded 95 SNPs from a total of 5252 bp, averaging one SNP
every 55 bp. Among these SNPs, 73 were heterozygous in the loci of
some individual cultivars. The SNPs distribution were: 58% transition,
40% transversion, and 2% InDels. There were also one di-nucleotide
polymorphism and one tetra-nucleotide deletion. The procedure of SNP
isolation from AFLP fragments can be useful for transferring AFLP
markers into sequence-tagged-site markers.
(271) Expression of the NRT1 Gene in Cornus and
Rhododendron
David R. Sandrock*1, Anita N. Azarenko2, Ruth M. Martin2,
Nahla V. Bassil3
1
University of Florida, Environmental Horticulture, Gainesville, FL, 32611; 2Oregon State
1020
final6_20July HS.indb 1020
University, Horticulture, Corvallis, OR, 97331; 3Agricultural Research Service, National
Clonal Germplasm Repository, Corvallis, OR, 97333
The NRT1 gene family encodes transport proteins with dual or low
affinity for nitrate. The objectives of this experiment were to develop a
system that could be used to compare the expression of the NRT1 genes
between species. This was accomplished by comparing sequences of
NRT1 homologues from various species and designing degenerate primers
in regions of high homology. These primers were used to amplify a region
of the NRT1 gene from species of interest. A 635 bp PCR product was
amplified from each species using the MD2-1 (5’ATGTTACCAAYWTGGGCMAC-3’) and MD2-2 (5’-GCCAMWARCCARTAGAAAT-3’)
primers. The PCR products were cloned and sequenced. At the nucleotide
level, Cornus sericea L. ‘Kelseyi’ and Rhododendron L. ‘Unique’ were
79.52% identical. Species-specific primers were designed and used
for RT-PCR to compare NRT1 expression in roots of hydroponically
grown C. sericea, C. sericea ‘Kelseyi’, and Rhododendron ‘Unique’.
The relative levels of NRT1 expression, normalized using 18S rRNA as
a standard, were ≈3.2 to 1.7 to 1.0 for C. sericea, C. sericea ‘Kelseyi’,
and Rhododendron ‘Unique’, respectively. This approach may eventually
be used to examine nitrate uptake potential in different taxa of plants at
different times during the growing season.
(272) DNA Markers Linked to the Resistance Gene of Scab
in Oriental Pear (Pyrus sp.)
Kang-Hee Cho*1, Il-Sheob Shin2, Seong-Sig Hong2, Ki-Taek Kim1,
Hwa-Suk Song1, Sang-Jo Kang2, Il Gin Mok3
1
National Horticultural Research Institute, Horticultural Biotechnology, Tap Dong 540-41,
Suwon, Gyeonggi Province, 441-440, Republic of Korea; 2National Horticultural Research
Institute, Fruit Research, I-mok Dong 475, Suwon, Gyeonggi Province, 440-706, Republic
of Korea 3National Horticultural Research Institute, I-mok Dong 475, Suwon, 440-706,
Republic of Korea
Pear scab caused by Venturia nashicola is one of the most important
diseases of oriental pear. Breeding a variety resistant to scab can be
improved through marker-assisted selection (MAS). Bulked segregant analysis (BSA) and amplified fragment length polymorphic
(AFLP) analysis were performed to identify DNA markers linked to
the scab-resistant gene (Vn) using a population from a cross between
PS2-93-3-98 (resistant parent) and Yali (susceptible parent). A total of
480 EcoR I/Mse I primer combinations were used to identify markers
specific to PS2-93-3-98 and resistant pool. Three AFLP markers linked
to Vn, E-AGT/M-CCA245, E-ATT/M-CCG300, and E-GGT/M-TCT225,
were selected. Linkage analysis between the selected markers and Vn
locus was conducted with 51 individual plants. The selected markers,
E-AGT/M-CCA245, E-ATT/M-CCG300, and E-GGT/M-TCT225, were
located at 3.9, 3.8, and 1.2 cm away from Vn, respectively. For practical application, we are currently converting selected markers to simple
PCR-based markers. The markers could be used to increase selection
efficiency in pear-breeding programs for scab resistance.
(273) Engineering Female Sterility for Horticultural Crops
Alan Smith*, Nicole Gardner, Elizabeth S. Zimmermann
University of Minnesota, Department of Horticultural Science, Saint Paul, MN, 55108
Female sterility is desirable in horticultural crops for many reasons,
including decreasing invasiveness and weediness, reducing nuisance
fruit production, promoting vegetative growth, and increasing flower
longevity and number. This study tested a method of creating female
sterility through genetic transformation of plants with a gene that ablates
tissue necessary for female fertility and reproduction. A gene construct
was created containing barnase, a cytotoxic RNAse, expressed with a
transmitting tract specific promoter from the tobacco gene sP41. The
sP41 gene encodes a (1,3)-β-glucanase in the transmitting tract of the
pistil of mature tobacco flowers. The construct also expressed barstar,
a barnase inhibitor, driven by the CaMV 35S promoter to protect
other plant tissues from unexpected barnase expression. Seed set data
taken after controlled pollinations showed tobacco plants transformed
with this construct had greatly reduced fertility in young flowers and
female sterility in mature flowers relative to nontransformed controls.
Light microscopy showed ablation of the transmitting tract tissue in
transformed plants. The expression of barnase with a transmitting tract
specific promoter is an effective way to reduce or eliminate female
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fertility. Due to the conservation of (1,3)-β-glucanase activity in the
styles of other plant species, this construct has potential for producing
female-sterile cultivars of other horticultural crops.
(274) Inter-and Intra-specific Variation in Yield and
Quality Traits of Chile Pepper Breeding Lines
Reddy R. Chinthakuntla*1, Frank Matta2, Rao S. Mentreddy3,
Umesh Reddy4, Padmavathi Nimmakayala4, Daniel Peterson5,
Om Prakash Vadhwa1
1
Alcorn State University, Department of Agriculture, Alcorn State, MS, 39096; 2Mississippi State University, Plant and Soil Sciences, Dorman, Mississippi State, MS, 39762;
3
Alabama A&M University, Plant and Soil Science, Huntsville, AL, 35802; 4West Virginia
State University, Plant Biotechnology, Dunbar, WV, 25064;5Mississippi State University,
Biotechnology, Mississippi State, MS, 39762
(275) Cloning of a Myrosinase cDNA from Horseradish
(Armoracia rusticana) Root and Its Heterologous
Expression in Spodoptera frugiperda Insect Cells
Xian Li1, Hans Bohnert2, Mary Schuler3, Mosbah Kushad*1
1
University of Illinois, Natural Resources and Environmental Sciences, Urbana, IL, 61801;
Department of Plant Biology; 3Department of Cell and Structural Biology
2
A full-length cDNA (ArMY1) encoding myrosinase (β-thioglucoside
glucohydrolase, EC 3.2.3.1) was cloned from horseradish (Armoracia
rusticana) root. ArMY1 has an open reading frame of 1614 nucleotides with a deduced protein of 538 amino acids and molecular mass
of 61.6 kD. ArMY1 shows highest overall amino acid identity (72%)
with Arabidopsis thaliana myrosinase TGG2. ArMY1 mRNA signal
of about 1.95 kb was detected in the leaves and roots of horseradish,
but not in the leaves of broccoli. Heterologous expression of ArMY1
in baculovirus-infected Sf9 cells resulted in an immunologically active
recombinant ArMY1 protein when probed with myrosinase-specific
monoclonal antibody 3D7 with apparent mass 65 kD. Phylogenetic
analysis showed that ArMY1 does not cluster with any of the current
myrosinase subfamilies, i.e., the MA, MB, and MC subfamilies, and
may represent a novel myrosinase subfamily in root tissue. This is the
first report of cloning of myrosinase cDNA from horseradish root. It
provides important sequence information that will enable further studies
of myrosinase expression patterns and their interaction with myrosinase–binding proteins and other myrosinase-associated proteins.
(277) Behavior of Glomus intraradices in Agave Roots
Transformed with Agrobacterium rhizogenes
Guillermo Rodríguez, Sergio Aguilar-Espinosa,
Eugenio Perez-Molphe Balch, María del Rocío Flores-Bello,
Javier Farias-Larios*, José Gerardo López-Aguirre
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The present work is the first report in vitro on root induction of Agave
salmiana Otto, using Agrobacterium rhizogenes. Several concentrations
of bacteria and acetosyringone were used, and different inoculation
sites were tested, such as leaves, shaft, and root. Incubation time in
darkness was 6 days. The transformed adventitious roots appeared 25
days after inoculation. The best treatment was when the shaft was inoculated with: 1 × 108 bacteria/mL and 100 μm acetosyringone; in this
treatment, induction of transformed roots was 57.5% in the inoculated
sites. The activity and presence of the foreign genes in the transformed
roots of A. salmiana were verified as follows: 1) histochemical staining for GUS activity was determined in 80% of the tested root; and 2)
molecular analysis via PCR was made to verify the presence of nptII
gene and rol B gene (both were present in 60% of the tested root). This
is the first report of the arbuscular mycorrhizal colonization on wild
roots and transformed roots of Agave with Glomus intraradices Schenck
and Smith. The result of the monoxenic culture was as follows: mother
spore germinated 5 days; the colonization of the transformed roots was
70%. Then we proceeded to the recovery of daughter spores, in which
we obtained an average 300 daughter spores per petri dish, 6 months
after inoculation.
Poster Session 17–Seed and Stand Establishment
19 July 2005, 12:00–12:45 p.m., Poster Hall–Ballroom E/F
POSTERS–TUESDAY
Chile pepper (Capsicum spp.) is the third most important vegetable crop
in the United States. The market value of chile peppers for spices and
condiments exceeds $650 million per year. With a growing Hispanic
population across the United States, the demand for high yielding, good
quality cayenne pepper continues to increase. In order to fulfill this
niche market, a study has been initiated to develop pepper varieties that
combine high yield potential with superior agronomic traits, including
insect and disease resistance, and fruit characteristics, using molecular
marker assisted breeding/selection. In preliminary trials, several F1
generations were created through inter- and intra-specific crosses among
220 germplasm lines belonging to six Capsicum sp. in the greenhouse.
Selected F1 progeny, parent lines, and selected accessions were planted
in single-row field plots the following summer. The crossing success
was higher within species than between. The genotypic variation was
significant for all parameters examined. The average percent germination
(81.1) of F1 progeny was 32% and 45% higher than that of the parent
lines and selected accessions, respectively. The F1 progeny were shorter
in height; more vigorous in growth, flowered early, and with fewer, but
heavier, fruits per plant out-yielded the parent lines and accessions by
50% and 120%, respectively. The study showed a marked heterosis in
F1 progeny compared to the parent lines and accessions. Microsatellite
genotyping to estimate genetic diversity and validation of markers that
are linked to various traits is in progress and will be discussed in the
presentation.
Universidad de Colima, Facultad de Ciencias Biológicas y Agropecuarias, Autopista ColimaManzanillo, Km. 40, Tecomán, Colima, 28100, México
(420) Germination and Radicle Elongation Responses
of Seven Vegetable Crops to Aqueous Extracts of Hairy
Vetch (Vicia villosa) and Cowpea (Vigna unguiculata)
Erin C. Hill*, Mathieu Ngouajio
Michigan State University, Horticulture, East Lansing, MI, 48824
Hairy vetch (Vicia villosa Roth) (HV) and cowpea [Vigna unguiculata
(L.) Walp.] (CP) are two leguminous cover crops used in vegetable
production systems. The residues of both species have been shown to
suppress weeds via allelopathic interactions; however, they may also
carry a risk of crop injury. A laboratory experiment was designed to
study the dose response of carrot, sweet corn, cucumber, lettuce, onion,
pepper, and tomato germination and radicle elongation to the aqueous
extracts of both HV and CP. Aqueous extracts of fresh, whole plants
were lyophilized to obtain a dry powder. Treatments of 0.00, 0.25, 0.50,
1.00, 2.00, 4.00, and 8.00 g dry extract/L of distilled water were applied
to 10 seeds on filter paper in petri dishes. The petri dishes were then
sealed and placed in the dark at 21 °C for 4 to 7 days, depending on
the species germination. After the incubation period, germination rates
and radicle lengths were recorded. Each treatment had 4 replications
and the full experiment was executed twice. Pepper germination was
reduced by increasing concentrations of HV extract; however, all other
crops were not affected by HV or CP extracts. The HV extract had a
significant effect on radicle elongation in carrot, corn, cucumber, lettuce, onion, and tomato. Inhibition of radical growth at 8 g·L-1 ranged
from 42% in cucumber to as high as 81% in carrot. The CP extract
had a negative effect on the radicle elongation of carrot, corn, lettuce,
and tomato. Inhibition at 8 g·L-1 ranged from 42% in carrot to 67%
in tomato. This study shows that both HV and CP extracts hold the
potential to negatively affect the listed crops. Therefore, studies need
to be done on the persistence of these effects in the field to maximize
weed control while avoiding crop injury.
(421) Light and Temperature Interactions in Promoting
Lettuce Seed Germination
Samuel Contreras*1, David Tay2, Mark Bennett1
1
The Ohio State University, Horticulture and Crop Science, Columbus, OH, 43210; 2The
Ohio State University, Ornamental Plant Germplasm Center, Columbus, OH, 43210
Lettuce seeds (Lactuca sativa var. acephala cv. Tango) were used
with the objective of determining the effect of temperature, light,
and their interactions in promoting germination. Under standard op-
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timal conditions (20 °C, light), the seed presented 100% germination
(radicle emergence 5 d after sowing). Different treatments evaluated
germination under dark conditions, with or without a red light break
(LB, 28.8 mmol·m-2) 48 h after sowing, and with different combination
of temperatures pre- (soaking temperature, ST) and post- (germination temperature, GT) the LB. Germination at constant 20 °C without
LB was less than 5%, and with LB, it was around 30%. However,
germination was close to 100% at GT of 20 °C when LB was applied
after a ST of 10 °C, and around 50% under the same conditions, but
without LB. When GT was 30 °C and LB was applied, germination
was less than 3% with ST = 30 °C, less than 10% with ST = 20 °C, and
around 100% when ST = 10 °C. With ST and GT of 10 °C and 30 °C,
respectively, and no LB, germination was less than 5%. Germination
at 10 °C constant, with and without LB, was around 90% and 0%,
respectively. When ST was 40 °C and LB was applied, germination
was around 40% at GT= 20 °C, but less that 3% with GT= 30 °C. In
summary, a severe inhibition of germination was observed when seeds
were germinated in dark, which was partially reversed by either a light
treatment or soaking at 10 °C, and fully reversed when both treatments
were applied together. Inhibition of lettuce germination at 30 °C was
observed when this temperature was applied after a light treatment,
but not when applied before. Possible implications of these results for
the phytochrome mechanism of action are discussed.
(422) Application of X-Ray in Flower Seed Technology
David Tay*, Joseph Tychonievich, Stephanie Burns
The Ohio State University, Ornamental Plant Germplasm Center, Columbus, OH, 43210
The Association of Official Seed Analysts adopted X-ray technology for
testing agricultural and forest tree seeds in 1979. It has not been applied
on flower seeds. To date, its use is still lacking, despite the relatively
simple and nondestructive nature of the test. One of the reasons for the
slow adoption is the lack of a simple X-ray unit that gives instant high
resolution digital images. The Faxitron MX-20, a cabinet X-ray unit
designed for high detail radiographic imaging of medical specimens,
fulfills this need. The high magnification capacity of 1×, 1.5×, 2×, 3×,
4×, and 5×, and the low kilovoltage (kV) provide enhanced image
performance with good quality contrast. The exposure time and X-ray
tube kV can be selected to produce the best images. Its laser locator
eases the positioning of a sample under examination accurately and
the 2- × 4-inch field of view digital camera with 10 lp/mm resolution
provides the instant high quality on-screen viewing of seed sample images. The most useful application at the Ornamental Plant Germplasm
Center is not in seed testing as recommended for agricultural and tree
seeds, but as a tool during seed cleaning to see in a matter of seconds
whether empty, immature, insect-damaged, and broken seed have been
removed. It has proven useful in Achillea, Alstroemeria, Aquilegia,
Aruncus, Aster, Baptisia, Begonia, Campanula, Chrysanthemum,
Coreopsis, Dianthus, Euphorbia, Geranium, Hemerocallis, Impatiens,
Iris, Lilium, Lupin, Lysimachia, Narcissus, Pelargonium, Penstemon,
Petunia, Phlox, Platycodon, Ranunculus, Rudbeckia, Salvia, Silene,
Stokesia, Tagetes, Talinum, Verbena, Veronica, and Viola.
(423) Effect of Seed Radiography on Seed Quality
David Tay*, Xiaolei Hu
1
The Ohio State University, Ornamental Plant Germplasm Center, Columbus, OH, 43210
Radiography is a simple and nondestructive technique to detect empty,
immature, and insect- and mechanically damaged seed during seed
processing and testing. However, there is a lack of information on the
effect of X-ray on seed quality despite recommendations by the Association of Official Seed Analysts for testing agricultural and forest
tree seeds since 1979. Two experiments were carried out using lettuce
seed of Seed Dynamics, Inc. (No. 52694) and Faxitron MX-20 cabinet
X-ray unit set at 20 kilovoltage (kV) for 20 seconds, a standard setting to observe many species of flower seeds. In both experiments, the
focus-object distance was 34 cm with no image magnification. The
treatments in Experiment 1 were 0 (control), 4, 8, and 12 times of Xray exposures and Experiment 2 were 0 (control), 15, 30, and 60 times
of X-ray exposures on non- and 5-hour imbibed seed. In Experiment
1, germination was done in 288-cell seedling trays in soilless potting
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final6_20July HS.indb 1022
mix under greenhouse conditions with four replications of 50 seeds
per replicate to observe germination rate, and cotyledon and young
leaf discoloration and deformation. Experiment 2 was analyzed using computerized seedling imaging system on germination paper to
examine seed vigor and germination rate. There were no significant
differences in germination rate in both the non- and imbibed seed in
the two experiments. The mean germination rates were 77.75% in
Experiment 1 and 94.81% in Experiment 2. No cotyledon and young
leaf discoloration and deformation were observed in Experiment 1 and
no significant differences in vigor index were found in Experiment 2.
The conclusion is that there was no observable effect of repeated Xray exposures up to 60 times at 20 kV and 20 seconds on a seed lot for
both non- and imbibed lettuce seed.
(424) Vigor Tests on Lettuce Seeds and Their Correlation
with Emergence
Samuel Contreras*, Margarita Barros
Pontificia Universidad Católica de Chile, Departamento de Ciencias Vegetales, Casilla
306-22, Santiago, Chile
The main objective of this study was to evaluate some of the available
seed vigor tests to predict lettuce (Lactuca sativa L.) seedling emergence.
Eight lettuce seed lots were evaluated by the following laboratory vigor
tests: germination (GT); accelerated aging (AA); saturated salt accelerated aging (SSAA); conductivity (EC); and seed vigor imaging system
(SVIS). Also evaluated were the percentage (EP) and speed (ES) of
the seed lots’ emergence under three conditions: seedling trays (ST)
filled with a mixture of peat (80%) and perlite (20%); boxes with a
clay loam soil (BS); and boxes with a mixture of clay loam soil (66%)
and sand [34% (BSS)]. Correlation coefficients among the laboratory
and emergence test results were calculated and significant differences
were found. The correlation coefficients between EC results and each
emergence parameter were nonsignificant, while AA results were only
significantly correlated with the emergence percentage for BSS. GT
values and emergence results were significantly correlated in all cases.
SSAA results were equally or more positively correlated than GT results
with the EP and, for the three sowing conditions, they were more correlated with the ES than GT values. Vigor index results from the SVIS
were significantly correlated with both emergence parameters, and its
correlation with emergence on ST (EP and ES) was greater than GT
values. The results of this study showed that SSAA and SVIS were the
best laboratory tests for lettuce seed vigor evaluation, especially for
seed lots to be used for plug seedling production.
(425) Effect of Shading on the Germination and
Vegetative Development of ‘Serrano’ Hot Pepper
(Capsicum annuum L.)
Marcelino Bazán-Tene*, Jaime Molina-Ochoa,
Enrique Alejandro Bracamontes-Ursúa
Universidad de Colima, Facultad de Ciencias Biológicas y Agropecuarias, Tecomán,
Colima, 28140, Mexico
Hot pepper (HP), Capsicum annuum (L.), is a solanum plant domesticated in Mesoamerica. It is currently widespread worldwide, and its
uses are varied, such as an excellent flavoring, pigment base, and as a
food resource with source of vitamins. The seven top world producers
of HP are China, Mexico, Turkey, Spain, United States, Nigeria, and
Indonesia. Mexico is producing about 623,238 t/year of fresh fruits
in 136,398 ha; Colima produced 17,181 t in 676 ha, with a mean of
27 t·ha-1. The culture of HP in Colima is facing certain limitations in
showing its productive potential, such as maintaining fertile and welldrained soils, and constant soil moisture; being weed-free during the
first weeks after transplanting; and sustaining plant uniformity into
transplantation. Transplantation is made in seed beds, but there is a
lack of scientific evidence on shade requirements in the seed nursery
to accelerate and improve plant quality for transplanting, and to impact
on fruit yield. The aim was to evaluate the effect of levels of shading
on the germination and vegetative development of ‘Serrano’ HP under
greenhouse conditions. Four levels of shading were evaluated using
mesh fabrics to produce 90%, 75%, and 50% shade, and a control
without shading on the seed beds. A completely randomized design
HORTSCIENCE, VOL. 40(4), JULY 2005
6/20/05 5:01:18 PM
with four treatments and four replications was used. The shading treatments reduced the germination period in about 1 day, increased the
percentage of germination with a range between 1.75% and 3.25%;
increased the plant height 0.83, 2.85, and 4.38 cm at 3, 6, and 10 days
post-emergence; increased the root biomass about 0.01 g/plant, and
0.24 g of fresh foliage with the 90% shade compared with the control.
Overall, a better agronomic performance of ‘Serrano’ HP was obtained
with 90% shading.
was observed during germination after the steeping treatments. These
results demonstrate that steeping in lime solutions could shorten the
period required for barley germination and similar conditions may be
useful for germination of other cereal and vegetable seeds.
(426) Evaluation of Pregerminative Treatments in
Soursop (Annona muricata L.) Seeds
Flower seed threshing and cleaning are challenging because many
flowers have tiny seed, e.g., the 1000-seed weight of Begonia is 0.01
g, and others have odd-shaped seed, e.g., Tagetes has pappus-bearing
seed and Fibigia has winged seed. There is a lack of information on
the threshing and cleaning of flower seeds. At the Ornamental Plant
Germplasm Center, a small-plot grain belt thresher was modified by
disengaging its winnower and a special chute installed to collect the
threshed seed and chaff together for cleaning. A custom-made threshing
board is used for small samples. The seed with chaff is passed through
screen with mesh size that allows all the seed to pass through so that
the big pieces of chaff are retained and separated, i.e., scalping. Accurate selection of the next scalping screen (SS) is critical so that the
mesh size is just right for at least 95% of the seed to pass through to
remove all the chaff larger than the seed. The seed is then sieved on a
grading screen (GS) of mesh size that retains at least 95% of the seed
to remove all the chaff smaller than the seed. A seed blower is used to
further separate the remaining chaff and empty seed based on weight
and surface area by adjusting the blowing velocity (BV). A vibratory
separator (VS) is used for species with round seed, e.g., Antirrhinum.
An X-ray machine is used to monitor the cleaning process. The SC,
GS, BV, and VT are given for Agastache, Anisodontea, Antirrhinum,
Aquilegia, Aster, Astilboides, Begonia, Belamcanda, Bergenia, Cleome,
Coreopsis, Dianthus, Eupatorium, Gaillardia, Geranium, Gypsophila,
Iris, Lilium, Lysimachia, Myosotis, Nothoscordom, Oenothera, Passiflora, Penstemon, Petunia, Platycodon, Ranunculus, Rudbeckia,
Silene, Stokesia, Synnotia, Tagetes, Talinum, Thalictrum, Verbena,
Veronica, and Zinnia.
Juan Manuel González Gonzalez*, Salvador Guzman Gonzalez,
Arnoldo Michel Rosales, Francisco Radillo Juarez,
Marcelino Bazan Tene, Fernando Cervantes T.
The most common spread of this species is sexual or by seed. In normal
conditions, the germination of the seeds of Anonaceae can increase
with pregerminative treatments prior to sowing. The objective was to
determine the best pregerminative treatment to increase germination
of soursop seeds. This study was carried out under the the dry, tropic
conditions of Tecomán, Colima, Mexico. The experimental design was
completely random with 12 treatments: 1) dip in water for 24 hours; 2)
dip in water for 24 hours + gibberellic acid (GA3) at 350 ppm; 3) dip
in water for 24 hours + GA3 at 500 ppm; 4) dip in water for 24 hours
+ GA3 at 1000 ppm; 5) mechanical scarification; 6) dip in water for 24
hours + mechanical scarification; 7) mechanical scarification + GA3 at
350 ppm; 8) mechanical scarification + GA3 at 500 ppm; 9) mechanical
scarification + GA3 at 1000 ppm; 10) GA3 at 350 ppm; 11) GA3 at 500
ppm; and 12) GA3 at 1000 ppm; and control. There were four repetitions
with 10 seeds in each experimental unit. The evaluated variables were
the percentage of germination and the number of days from planting
to emergence. To record results, analysis of variance and Tukey’s test
averages were used. The major percentage of germination resulted
from the seeds treated with soaking in water for 24 hours plus GA3 to
350 ppm, dip in water for 24 hours plus scarification and GA3 at 1000
ppm, and equalized statistically to the control. For the number of days
from planting to emergence, the treatment with mechanical scarification + GA3 at 500 ppm was statistically better. The use of gibberellic
acid with mechanical scarification diminishes the dormancy of soursop
seeds, producing plants in a relatively short period.
(427) Seed Germination after Steeping in Saturated Lime
Solutions
1
2
Augusto Trejo-Gonzalez* , Marita Cantwell
1
UPIBI-IPN, Bioprocesos, Av. Acueducto de Guadalupe, Col. La Laguna-Ticoman, Mexico;
University of California, Plant Sciences, Davis, CA, 95616
2
A lime solution is an efficient starch gelatinization agent during the
traditional process of nixtamalization of corn for tortilla production.
Although the saturated Ca(OH)2 solution is usually heated to speed the
process, similar physical-chemical changes occur to corn steeped at
room temperature. In addition, the steeped grains are capable of rapid
germination. In this study we explored whether, in barley grains subjected to the same steeping conditions, there would be an acceleration
of biochemical changes for the production of malt. Barley grains cv.
Esmeralda six-row were steeped in saturated solutions of lime from
0% to 2% (w/w) at 18 to 23 °C for up to 72 hours. After treatment, the
grains were washed with water and placed in a germination cabinet
at 20 ± 2 °C and 90% RH for up to 96 hours to germinate. Activity of
α-amylase (U/mg protein), sprout length (cm), seed viability (tetrazolium test), and respiration rates were determined. Scanning electron
micrographs were prepared. There was a very rapid uptake of lime
solution by the barley grains during the first 30 hours of treatment.
The barley grains were 98% viable after all periods of steeping. Grains
steeped 24 hours and germinated 70 hours had the highest activity of
α-amylase, longest sprout length and highest percentage of germination.
Under SEM, chemical gelatinization of starch grains was observed in
barley sections after different steeping treatments, and starch breakdown was observed in grains during germination. No fungal growth
HORTSCIENCE, VOL. 40(4), JULY 2005
final6_20July HS.indb 1023
David Tay*
The Ohio State University, Ornamental Plant Germplasm Center, Columbus, OH, 43210
POSTERS–TUESDAY
Universidad de Colima, Facultad de Ciencias Biológicas y Agropecuarias, Tecomán,
Colima, 28100, México
(428) Seed Threshing and Cleaning in Flowers
(429) “Artificial Exosperm” Development Using
Antistress, Antioxidant Compounds for Promoting and
Synchronizing Seedling Emergence at Limiting Low
Temperature and Moisture Conditions in Carrot
Rowan Briscoe*1, Rajasekaran Lada1, Claude Caldwell1,
Kevin Sibley2, Christine Pettipas1, Azure Stiles1
1
Nova Scotia Agricultural College, Plant and Animal Sciences, Truro, Nova Scotia, B2N
5E3, Canada; 2 Nova Scotia Agricultural College, Engineering
Producing carrots with optimal root grades is the most critical aspect
of carrot production for maximizing profits. Desired root grades can
be optimized by maintaining optimal plant population. While precision
seeding helps to seed required seeding rate, obtaining optimum seed
germination and uniform emergence, especially in mineral soils and
under cold and dry climates, have been great challenges to carrot producers around the world. Therefore, stand establishment is critical for
optimizing yield and quality in carrots. Experiments were conducted to
identify suitable germination and emergence promoters (GEPs) that will
promote early and uniform emergence under temperatures of 5 °C and
20 °C and under 20% FC and 40% FC combinations. GEPs, belonging to
both natural and synthetic antistress, antioxidant groups of compounds,
and mineral salts were used. Carrot seeds of cv. Oranza were used in this
study. Seeds were preconditioned with various GEPs, then submerged
into laponite RD gel that was used as a potential “artificial exosperm”
for carrot seeds. Data on emergence was collected and emergence and
vigor value was calculated. Under ideal conditions, that is, at the 20 °C
and 40% FC combination, there was no significant difference between
treated seeds and untreated control. Germination was delayed at the
5 °C and 20% FC combination. However, seeds preconditioned with
GEP-PN1.5%, GEP-LU at 1 mg·L-1, GEP-CA at 10 mg·L-1, GEP-AA at
100 mg·L-1 and GEP-SD at 10 mg·L-1 all promoted emergence resulting
in the highest number of seedlings emerged at 5 °C and at 20% FC.
Enhanced emergence under low temperature and low moisture may
perhaps be due to synthesis of specific proteins.
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6/20/05 5:01:20 PM
Poster Session 18—Weed Management
19 July 2005, 12:00–12:45 p.m., Poster Hall–Ballroom E/F
(339) Preemergence Weed Control in Container-grown
Herbaceous Perennials
James E. Klett*1, David Staats1, Matt Rogoyski2
1
Colorado State University, Department of Horticulture and Landscape Architecture, Fort
Collins, CO, 80523; 2Colorado State University, Department of Horticulture and Landscape
Architecture, Grand Junction, CO, 81503-9621
During the 2004 season, preemergence herbicide was applied to 12
container-grown herbaceous perennials and woody plants and evaluated for weed control, phytotoxicity, and effect on plant growth. The
herbicide and rates were: pendimethalin (Pendulum 2G) 908 g (label
rate), 1816 g, and 3632 g/acre a.i. Herbicides were applied to lady’s
mantle (Alchemilla mollis), purple rock cress (Aubretia species), blue
wild indigo (Baptisia australis), pink pussytoes (Antennaria dioica
var. rosea), common sneezeweed (Helenium autumnale), redhot poker
(Kniphofia uvaria), showy goldenrod (Solidago speciosa), heartleaf
foamflower (Tiarella cordifolia), lavender (Lavendula angustifolia),
blue flax (Linum perenne), catmint (Nepeta ×faassenii), and hen and
chicks (Sempervivum tectorum). At 32 and 117 days after application,
plants were evaluated for phytotoxicity. No phytotoxicity symptoms
were apparent on any of the plants tested. Weed control was good in most
cases with this herbicide but it did not control all weeds. Increasing the
rates from 1× (label rate) did not significantly improve weed control.
(340) Root Hardiness and the Influence of DNA
Herbicides in Overwintered Containers
Michele Bigger*, Hannah M. Mathers
The Ohio State University, Hort. and Crop Science, Columbus, OH, 43210
A limiting factor in container production is cold temperature. Young
roots have been found to be less hardy than mature roots (Steponkus,
1976; Studer et al., 1978). Proper overwintering procedures are essential to assure a viable crop in the spring. A common overwintering
practice is the application of a preemergent dinitroanaline (DNA)
herbicide prior to covering. The objectives of this research were to: 1)
determine young and mature root hardiness values for containerized
plants that did and did receive DNA herbicides prior to overwintering;
2) investigate differences in regrowth potential between untreated and
DNA herbicide treated containers 30, 60, and 180 days after freezing
(DAF). Research began in June 2003 and concluded Mar. 2004. In Aug.
and Oct. 2003, herbicide treatments of 1× oryzalin (2.0 lb/acre a.i.),
prodiamine (2.0 lb/acre a.i.), pendimethalin (3.0 lb/acre a.i.), trifluralin
(2.0 lb/acre a.i.), or no treatment (control) was applied to the plants.
In Jan. or Mar. 2004, plants were frozen to temperature treatments
of, 0, –5, –10, –15, or –20 °C. After freezing, they were placed in a
heated greenhouse and evaluated for regrowth. Regrowth and hardiness were evaluated two ways: by a visual rating score (0-10), where
0 = dead and 10 = healthy; and plant live height. Results pooled over
all species, temperatures, sampling dates at 30 DAF show prodiamine
significantly increased hardiness (23.7%) compared to the control.
Results pooled over all species, temperatures, sampling dates, and
all DAF show prodiamine significantly increased regrowth potential
(24.5%) compared to the control. Both sampling date and DAF were
significant when pooling over all species, temperatures, and herbicide
treatments, indicating root injury had occurred.
(341) Weed Resistant Cowpeas: Experiments and Models
Guangyao Wang1, Jeff D. Ehlers1, Philip A. Roberts2,
Eddie J. Ogbuchiekwe1, Milton E. McGiffen, Jr.*1
1
University of California, Botany and Plant Sciences, Riverside, CA, 92521-0124; 2University of California, Nematology, Riverside, CA, 92521
Competitive cover crop varieties are needed to reduce weed problems
and herbicide use. Identifying specific crop traits related to competitive ability would provide breeders with useful information that could
be used to develop an ideotype for highly competitive cover crop
varieties. Cowpea varieties with different growth habits were grown
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final6_20July HS.indb 1024
with sunflower or purslane to determinate which growth habit (erect,
semi-erect, and prostrate) is more likely to be most competitive with
tall or short growing weeds. Regression models were used to analyze
additive and replacement series experiments. The results showed that
erect varieties were more competitive with weeds than semi-erect varieties and prostrate varieties. However, the simple regression models did
not provide much information about competitive mechanisms helpful
to breeders. An ecophysiological model, INTERCOM, was used to
understand competitive mechanisms. Validated INTERCOM model
provided us with more information about competitive cover crop traits,
including competitive growth habit.
(342) Cool-season Living Mulches for Florida
Carlene A. Chase*, Odemari S. Mbuya
1
University of Florida, Horticultural Sciences, Gainesville, FL, 32611-0690; 2Florida
A&M University, Agronomy Program & Center for Water Quality, Tallahassee, FL,
32307-4100
Living mulches between beds of polyethylene-mulched vegetable
crops may suppress weeds and decrease surface and ground water
contamination by pesticides. They should be either low growing or
amenable to mowing and should withstand traffic. Twelve winter cover
crops were planted in north (N.) and north central (N.C.) Florida in
Fall 2004: black oats (Avena strigosa cv. Soilsaver), annual ryegrass
(Lolium multiflorum cv. Gulf), rye (Secale cereale cv. Wrens Abruzzi),
hard fescue (Festuca longifolia cv. Oxford), white clover (Trifolium
repens cvs. Dutch white and New Zealand white), berseem clover (T.
alexandrinum cv. Bigbee), crimson clover (T. incarnatum cv. Dixie),
subterranean clover (T. subterraneum cv. Mt. Barker), arrowleaf clover
(T. vesiculosum cv. Yuchi), a barrel medic (Medicago trunculata cv.
Parabinga), and a disc × strand medic (M. tornata × M. littoralis cv.
Toreador). Black oats, rye, and annual ryegrass established quickly
and suppressed winter annual weeds. Canopy development of the other
species was poor. Shoot biomass was greater in N. Florida than in N.C.
Florida. The highest shoot biomass occurred with black oats. By 8 weeks
after planting (WAP) rye and annual ryegrass had similar amounts of
biomass, but by 16 WAP the yield of rye was greater. At some harvests,
biomass with wheel traffic or mowing was lower than without, but
black oats, rye, and ryegrass did not succumb to these treatments. Of
the legumes, only crimson clover and ‘Toreador’ medic in N. Florida
produced sufficient biomass by 16 WAP to permit a harvest. Black oats,
rye, and annual ryegrass appear to be the best living mulch candidates;
however, black oats would require more frequent mowing.
(343) Weed Control in Vineyard Following Fall and
Spring Application of Selected Herbicide Combinations
Sorkel Kadir*1, Kassim Al-Khatib2
1
Kansas State University, Horticulture, Manhattan, KS, 66506; 2Kansas State University,
Agronomy, Manhattan, KS, 66506
Soil residual herbicides registered for use on grapes can be applied from
fall to spring, before weed emergence. However, ample early-spring
moisture and warm weather may enhance weed emergence before
herbicide application in the spring and prevent timely application.
Therefore, fall application of herbicides can be beneficial if herbicides
would provide adequate weed control in the following spring. Warm and
wet winters may enhance herbicide degradation and shorten herbicide
residual activity that result in poor weed control the following spring.
Fall and spring application of oryzalin or norflurazon applied alone or
in combination with diuron, simazine, or oxyfluorfen were evaluated
for weed control in commercial vineyards at Oskaloosa and Eudora
in northeast Kansas in 2003 and 2004. Weeds were not controlled
adequately with oryzalin or norflurazon applied alone. At the end of
the growing season, however, weed control was greater with spring
than fall application. In addition, weed control with norflurazon was
slightly greater than oryzalin. Norflurazon or oryzalin applied in combination with simazine, diuron, or oxyfluorfen controlled more weeds
than norflurazon or oryzalin applied alone. The greatest control was
with norflurazon or oryzalin applied with oxyfluorfen. In general, all
herbicide combinations applied in the spring and fall provided similar
weed control 4 months after spring application. However, at the end
HORTSCIENCE, VOL. 40(4), JULY 2005
6/20/05 5:01:21 PM
of the growing season, weed control was 10% to 20% greater when
herbicides applied in the spring than fall. This study showed that acceptable weed control can be achieved when norflurazon or oryzalin
is applied with oxyfluorfen and diuron in the fall.
Poster Session 19—Pest Management
19 July 2005, 12:00–12:45 p.m. Poster Hall–Ballroom E/F
(362) Assessment of Woody Ornamental Plants for
Resistance to Three Meloidogyne Species
Jyotsna Sharma*1, Jim Rich2
1
University of Florida, Environmental Horticulture, Quincy, FL, 32351; 2University of
Florida, Entomology and Nematology, Quincy, FL, 32351
(363) Effect of Visible Light Wavelengths on the
Population Growth Rate of the Two-spotted Spider Mite
(Tetranychus urticae Koch.)
Takeshi Suzuki*, Hiroshi Amano, Toyoki Kozai
Chiba University, Faculty of Horticulture, Chiba, 271-8510, Japan
The two-spotted spider mite (Tetranychus urticae Koch.) has a
worldwide distribution and is one of the most harmful agricultural
pests for a variety of plant species. To reveal a visible light wavelength
that reduces the population growth rate (as rm, unit: d–1) of the mite,
we investigated the rm under wavelength peaks of 468, 515, and 658
nm with half bandwidths of 23, 44, and 22 nm using blue, green, and
red light-emitting diodes, respectively. In all treatments, light intensity
was set at 2.3 W·m–2 with a light period of 16 h·d–1, and air temperature was set at 25 °C. The survival percentage (lx) and the number of
eggs deposited per female (mx) on each age (x, unit: d) were determined to
calculate the rm by the following equation: Σexp(–rm · x)· lx /100 · mx = 1. The
rm and the total mx decreased with increasing wavelength. This result shows
that the population growth rate can be reduced under red light (658 nm).
(364) Evaluation of Beneficial Microorganisms for
Controlling the Wilt Caused by Fusarium oxysporum f. sp.
melonis on Cantaloupe Plants under Greenhouse Conditions
1
2
1
INIFAP, Campo Experimental Tecomán, Colima, 28100, México; 2Universidad de Colima,
Facultad de Ciencias Biológicas y Agropecuarias, Tecomán, Colima, 28100, México
Development of resistance to chemical pesticides has been reported in
about 150 plant pathogenic species, mostly fungi. Biocontrol of plant
pathogens is an alternative to chemical pesticides. Actually, there are
products formulated with beneficial microorganisms, such as mycorrhizal fungi, rhizobacteria, antagonistic fungi, and others. The objec-
final6_20July HS.indb 1025
Eva Judith Hueso*1, Jaime Molina-Ochoa1, Jalil Fallad-Chávez2,
Roberto Roberto Lezama-Gutiérrez3, Marilú López-Edwards3,
Javier Farías-Larios3
1
Universidad de Colima, Mexico, Nematology, Crucero de Tecomán., Colima, 28100,
Mexico; 2Universidad de Guadalajara, Engineering, Autlan de Navarro, Jalisco, 48900,
Mexico; 3Universidad de Colima, Mexico, Control Biologico, Crucero de Tecomán.,
Colima, 28100, Mexico
Scyphophorus acupunctatus is the main pest of Agave tequilana. Its
adults are vectors of Erwinia carotovora, which causes plant destruction. The susceptibility of S. acupunctatus larvae to various strains
of entomopathogenic nematodes has been demonstrated previously
(Molina et al., 2004). In the current paper, the use of seven different
concentrations: 0, 10, 20, 50, 100, 200, and 500, of infected juveniles
per larva in petri dishes containing a filter paper against Steinernema
carpocapsae strains All, Ca, and Fl, and also against native insolated
N1, N2, N4, belonging to the genera Steinernema sp. The studies were
conducted under laboratory conditions to determine the susceptibility of
S. acupunctatus larvae to entomopathogenic nematodes. One hundred
percent mortality of S. acupunctatus larvae was achieved by S. carpocapsae strains All, Ca, and Fl with exposure to 100 infected juveniles. In
the case of native isolates, N2 registered 95% mortality, and for N4 and
N1, mortality registered was 75%. An analysis of variance was conducted
in order to determine whether strain or isolate had the highest virulence
against S. acupunctatus larvae. Means for S. acupunctatus larvae by entomopathogenic nematodes presented significant differences (F = 57.01;
df = 55, 223; P < 0.0001), resulting in two levels. At the first level, S.
carpocapsae All, Fl, and Ca are statistically the same as isolate N4. At
the second level, the isolates N4 and N1 are statistically the same. The
results indicate the high susceptibility of S. acupunctatus larvae. The
infectivity of native isolates as well as S. carpocapsae strains All, Fl,
and Ca are associated with the symbiotic bacterium Xenorharbdus sp.,
suggesting they have potential for use against S. acupunctatus larvae.
Poster Session 20—Pomology–Culture/Production/
Management
2
Mario Orozco-Santos , Javier Farías-Larios* , Jaime Molina-Ochoa ,
José Gerardo López-Aguirre2
HORTSCIENCE, VOL. 40(4), JULY 2005
(365) Susceptibility of Scyphophorus acupunctatus Gyllenhal
(Coleoptera: Curculionidae) Larvae to Entomopathogenic
Nematodes Steinernema (Rhabditida: Steinernematidae)
POSTERS–TUESDAY
Plants infected with Meloidogyne spp. (root-knot nematodes) often
are stunted and lose aesthetic value due to chlorosis, wilting, and leaf
margin necrosis. We assessed reproduction of three root-knot nematode
species, Meloidogyne arenaria, M. incognita, and M. javanica, on five
plant taxa native to the southeastern U.S. The plant taxa included were:
Hydrangea quercifolia ‘Oakleaf’, Viburnum obovatum ‘Densa’, Itea
virginica ‘Little Henry’, Illicium parviflorum, and Clethra alnifolia
‘Ruby Spice’. Three commonly grown non-native shrubs, Ligustrum
japonicum ‘Texanum’, Ilex crenata ‘Compacta’, and Buxus microphylla
‘Wintergem’, also were included in the study to serve as susceptible,
positive controls. Highest gall rating (10) was observed on roots of I.
crenata ‘Compacta’ infected with M. incognita, but highest number
of eggs (6397 eggs/g of roots) was observed in plants of this cultivar
inoculated with M. javanica. Few or no galls were observed on roots
of the five native plant taxa, and nematode eggs were recovered only
from roots of I. virginica ‘Little Henry’ inoculated with M. arenaria and
M. javanica (13 and 20 eggs/g of roots, respectively). Fresh weights of
shoots or roots were not affected by nematode inoculation. Due to lack
of root gall development and little or no reproduction on the native taxa,
we conclude that these are resistant or immune to the three species of
Meloidogyne and might be suitable for planting in infested soil.
tive was to evaluate the development of Fusarium oxysporum f. sp.
melonis (FOM) on melon plants inoculated with commercial biological
formulations based on beneficial microorganisms. Twelve treatments
were evaluated: T1) VAM media nursery + FOM; T2) Hortic Plus +
FOM; T3) BioPak F + FOM; T4) Glomus intraradices + FOM; T5)
FOM; T6) control; T7) VAM media nursery; T8) Hortic Plus; T9)
BioPak F; T10) Glomus intraradices; T11) FOM + Mancozeb wp80;
and T12) FOM + BioPak F. The melon cultivar used was ‘Colima’
(Peto Seed Co.). Seeds were planted in Styrofoam growing containers
containing coconut fiber powder as substrate. One seed was planted
per cell and maintained until transplanting. Plants were transplanted
to pots containing sterile soils 13 days postemergence. Inoculation of
treatments with Fusarium was made with a concentrated suspension at
1 × 106 conidia/mL. For inoculation with beneficial microorganisms,
manufacturer specifications were followed. A completely randomized
design with 12 treatments and 12 replications was used to estimate
the incidence of Fusarium, number of leaves, leaf area, root biomass,
and percentage of roots colonized by mycorrhizal fungi. Overall, T10
showed the best behavior in all variables. Inoculation of cantaloupe
plants with Fusarium affected their performance, but those treatments
including mycorrhizal fungi enhanced their performance withstanding
the damage by Fusarium.
19 July 2005, 12:00–12:45 p.m. Poster Hall–Ballroom E/F
(309) Effect of Chitin-incubated Solution (CIS) Spray on
Tree Growth and Fruit Quality of ‘Niitaka’ Asian Pear
Wol-Soo Kim1, Jung-An Jo1, Soon-Ju Chung1, Kil-Yong Kim1,
Hyun Sug Choi*
1
Chonnam National University, Department of Horticulture, 300 Yongbong-dong, Gwangju,
1025
6/20/05 5:01:22 PM
500-757, Korea;2Chonnam National University, Department of Agrochemical; 3University
of Arkansas, Fayetteville, Arkansas, 72701
The shells of crab, shrimp, beetles, etc., could be decomposed by
chitinase to chitin, calcium, and protein, respectively. We incubated
the mixture solution of 1.5 kg crab shell, 1.5 kg multinutrient, 2 kg
compost with microorganisms to decompose the chitin substance,
3 kg sugar, and 700 L water at room temperature for 7 days. During
the incubation, aeration with an air pump was essential. We sprayed
the chitin-incubated solution (CIS) after filtering to ‘Niitaka’ pear
(Pyrus pyrifolia) trees at 15-day intervals from May to Sept. 2004.
Leaf area, leaf thickness, leaf specific weight, and chlorophyll contents
were increased by the treatment with CIS. In fruit characteristics,
fruit weight, soluble solids, fruit firmness, and Hunter values “a” and
“b”were increased by the CIS treatment. Flesh browning after peeling
the fruit was delayed by the CIS treatment, and polyphenoloxidase
(PPO) activities were lowered.
(310) Peach Orchard Systems Management Trial: The
First Six Years
and preplant root dips. Both trials examine long-term productivity and
tree survival. Second, we are examining the use of systemic fungicide
injection into infected trees to protect trees around infection foci. Third,
we are trying to develop a genetically modified ARR-resistant rootstock.
We have inserted the gene encoding the gastrodia antifungal protein
(GAFP—a low molecular weight lectin that binds mannose and chitin)
from a Chinese orchid into tobacco (model herbaceous system) and
plum (model Prunus system). GAFP has antifungal activity against
several basidiomycete root rot pathogens. Pathogenicity tests with
transformed tobacco plants show enhanced tolerance to several root
rot pathogens when compared to nontransformed plants. Transformed
plums are being multiplied for pathogenicity tests.
(312) Replant Apple Tree Performance, and Rhizotron
Observations of Root Development, Distribution, and
Survival for Three Rootstock Clones in a New York
Orchard
Shengrui Yao*, Ian A. Merwin, Michael G. Brown
Desmond R. Layne*, Eric J. Hitzler
Cornell University, Department of Horticulture, Ithaca, NY, 14853
Clemson University, Horticulture, 177 Poole Agriculture Building, Clemson, SC, 29634-0319
Rhizotron observations enabled us to compare the performance of three
apple (Malus ×domestica) rootstock clones following different pre-plant
soil treatments in an apple replant study at Ithaca, NY. Trees were planted
in Nov. 2001, with one minirhizotron tube per tree in three replicate
plots of three rootstocks (M7, CG30, and CG6210), three pre-plant soil
treatments (fumigation, compost amendment, and untreated controls),
and two planting positions (within the old tree rows, or in the old grass
lanes). Monthly root observations were conducted during the 2003
and 2004 growing seasons. There were substantially fewer new roots
observed in the first bearing year (2004) than the previous nonbearing
year (2003), for all three rootstocks. A root-growth peak in early July
accounted for more than 50% of all new roots in 2003, but there was
no midsummer root growth peak in 2004. Neither pre-plant soil treatments nor old row or grass-lane planting positions had much influence
on root growth. The median lifespan for roots of CG6210 was twice as
long as that of CG30 and M7 in 2004. Also, CG6210 had more roots
below 30-cm depth, while M7 had more roots from 11–20 cm. Trees
grafted on CG6210 were bigger and yielded more fruit in the third year
after planting, compared with trees on CG30 and M7 rootstocks. Crop
load severely inhibited new root development and changed root-growth
dynamics during the first cropping year, with a surge in root growth
after fruit harvest in Oct. 2004. Rootstock genotype was the dominant
influence on root lifespan and distribution, compared with pre-plant
soil fumigation, compost amendments, or replanting positions within
the previous orchard rows or grass lanes.
In 1999, a trial was established at the Clemson University Musser Fruit
Research Farm to investigate the effects of training system/tree density,
rootstock, and irrigation/fertilization on tree growth, productivity and
profitability. The replicated trial comprised three training systems/tree
densities (open center–332 trees/ha; quad V–664 trees/ha; and perpendicular V–996 trees/ha). The two rootstocks used were Lovell and
Guardian. Three irrigation/fertilization treatments included: natural
rainfall only plus granular program; supplemental irrigation plus granular; and supplemental irrigation plus fertigation at a reduced nitrogen
rate from the granular program. The scion was the popular midseason
cultivar Redglobe. There were a total of 18 treatment combinations
replicated 4 times with 5 trees per treatment plot. Soil moisture was
determined by TDR and pan evaporation monitored by weather station.
Seventy-two minirhizotron tubes were installed in 2002 to monitor fine
root growth. During 1999–2001, drought conditions limited rainfall to
35% below the annual average. Spring freeze events in 2001 and 2004
reduced crop load disproportionately in shorter, open-center trees. As
tree density within the tree row increased, trunk cross sectional area
(TCA) decreased. Trees on Guardian rootstock had significantly greater
TCA than Lovell each year. Trees that received supplemental irrigation had greater TCA than nonirrigated trees each year. By reducing N
rate through fertigation, TCA was reduced. Cumulative yield was not
affected by training system/tree density. Cumulative yield was not affected by rootstock. Cumulative yield was 7% greater by supplemental
irrigation. Pruning, thinning and harvesting was easier in V-systems
than for open center trees.
(313) Climatic Effects on Four Low-chill Peach Cultivars
in North Central and Central Florida
(311) Armillaria Root Rot of Peach: A Multipronged
Approach
Todd Wert, Jeffrey G. Williamson*, Robert E. Rouse, E. Paul Miller
Desmond R. Layne*1, Guido Schnabel2, Kerik Cox2, Ralph Scorza3,
Karen Bussey1
Four low-chill peach cultivars were evaluated for vegetative and reproductive growth, fruit quality, and yield in north central and central
Florida. Twenty-trees (five of each cultivar) were planted at each site
in Feb. 2002. Prior to budbreak in the spring of 2004 and 2005, three
shoots of average length and diameter were selected at a height of
1.5–2.0 m and the number of vegetative and flower buds was recorded
for each shoot. Percentage of bloom was estimated, and the number
of open flowers on selected shoots was measured weekly. Trees were
harvested twice per week starting in mid-April in central Florida,
and in late April in north central Florida. Total number and weight of
marketable fruit was measured for each tree. Ten representative fruits
were selected from each tree at each harvest. Fruit were measured
for blush, weight, and size. Soluble solids, TAA, and pressure were
determined for five fruit from each 10-fruit sample. Preliminary results
indicate a higher mean number of blind nodes in central Florida and a
higher mean number of flower buds in north central Florida. In central
Florida, 90% bloom was about 4 days earlier than north central Florida.
Fruit number and individual fruit size, weight, and marketable yield
were higher in north central Florida than in central Florida. Fruit blush
1
Clemson University, Horticulture, 177 Poole Agriculture Building, Clemson, SC, 29634;
Clemson University, Entomology, Soils and Plant Sciences; 3Appalachian Fruit Research
Station, USDA-ARS, Kearneysville, WV, 25430
2
Armillaria root rot (ARR) of peach caused by the soil-borne basidiomycete fungus Armillaria tabescens is causing premature decline and
mortality of peach trees on most southeastern U.S. peach farms. Soil
inoculum may be present both in former peach orchard sites and on
sites that were once in hardwood forest. The fungus is protected under
the bark of dead root pieces and may survive up to 100 years at various
depths in the soil profile. No commercially available rootstocks are
resistant to ARR. Since 2002, we have embarked on a multipronged
strategy to develop control options to combat ARR. First, we have two
replicated trials on commercial grower replant sites with a history of
ARR. Trial 1 compares four preplant fumigation treatments (none,
Telone II, methyl bromide, and Enzone), three rootstocks (Lovell,
Halford, and Guardian) and preplant root dips with endomycorrhizal
fungi. Trial 2 compares the use of raised beds, root collar excavation
1026
final6_20July HS.indb 1026
University of Florida, Horticultural Sciences Department, Gainesville, FL, 32611
HORTSCIENCE, VOL. 40(4), JULY 2005
6/20/05 5:01:24 PM
was higher in central Florida than in north central Florida and tended
to increase as the season progressed. In north central Florida, blush
decreased slightly throughout the season.
(316) Development of Rootstocks to Promote Early
Bearing in Pawpaw
(314) Geneva® 41: A New Fire Blight Resistant, Dwarf
Apple Rootstock
Kentucky State University, Land Grant Program, Frankfort, KY, 40601
Gennaro Fazio*1, Herb S. Aldwinckle2, Terence L. Robinson3,
James Cummins3
1
Cornell University, USDA ARS, Plant Genetic Resources Unit Geneva, Geneva, NY,
14456; 2Cornell University NYSAES, Plant Pathology, Barton Labs; 3Cornell University
NYSAES, Horticultural Sciences, Hedrick Hall
(315) Geneva® 935: A New Fire Blight Resistant, Semidwarfing Apple rootstock
Gennaro Fazio*1, Herb S. Aldwinckle2, Terence L. Robinson3,
James Cummins3
1
USDAARS, Plant Genetic Resources Unit Geneva, Cornell University, Geneva, NY, 14456;
Cornell University NYSAES, Plant Pathology, Barton Labs, Geneva, NY, 14456; 3Cornell
University NYSAES, Horticultural Sciences, Hedrick Hall, Geneva, NY, 14456
2
The Geneva® Apple Rootstock Breeding program, which was initiated
in 1968 by Dr. James Cummins and Dr. Herb Aldwinckle of Cornell
University and which has been continued as a joint breeding program
with the U.S. Dept. of Agriculture Agricultural Research Service
(USDA-ARS) since 1998, has released a new semi-dwarfing apple
rootstock which is named Geneva® 935 or G.935. G.935 (a progeny
from a 1976 cross of ‘Ottawa 3’ × ‘Robusta 5’) is a selection that has
been widely tested at the New York State Agricultural Experiment Station in Geneva, N.Y., in commercial orchards in the United States and
at research stations across the United States and Canada. G.935 is a
semi-dwarfing rootstock that produces a tree slightly larger than M.26.
G.935 is the most precocious and productive semi-dwarf rootstock we
have released. It has had similar yield efficiency to M.9 along with
excellent fruit size and wide crotch angles. It showed no symptoms of
winter damage during the 1994 test winter in N.Y. G.935 is resistant to
fire blight and Phytophthora; however. it is susceptible to infestations
by woolly apple aphids. G.935 has shown tolerance to replant disease
complex in several trials. It has good propagation characteristics in the
stool bed and produces a large tree in the nursery. G.935 has better
graft union strength than M.9, but will require a trellis or individual tree
stake in the orchard to support the large crops when the tree is young.
G.935 will be a possible replacement for M.26. Suggested orchards
planting densities with this rootstock are 1,500-2,500 trees/ha. It has
been released for propagation and sale by licensed nurseries. Liners
will be available in the near future.
HORTSCIENCE, VOL. 40(4), JULY 2005
final6_20July HS.indb 1027
The propagation of clonal rootstocks for the pawpaw [Asimina triloba
(L.) Dunal] has been unsuccessful; therefore, nurseries currently graft
cultivars onto rootstock derived from locally available seed of diverse
genetic origin. Great variation in pawpaw scion growth and suckering is observed with this seedling rootstock and grafted trees are also
slow to come into production, often producing fruit 5 to 6 years after
planting. In an effort to develop superior seedling rootstocks for pawpaw cultivars, seedstock was evaluated from the cultivars PA-Golden
(#1), Sunflower, Susquehanna, NC-1, K8-2, and commercially available seed (RVT). The objectives of the experiment were to determine
if: 1) genotype and seed size influenced vigor of greenhouse-grown
container seedlings; 2) graft compatibility and growth rate of scions
would vary by rootstock; and 3) scion precocity was influenced by
various seedling rootstocks in the field. Greenhouse experiments were
conducted in 2002, 2003, and 2004, and each year all seedstocks had
a high germination percentage (95%) and uniform size within each
seedstock. Seed size was an important factor in determining vigor
in container production. Seed of ‘Sunflower’ was large (1.65 g/seed)
and consistently produced vigorous seedlings that were able to be
chipbudded within 6 months. Seed of the selection K8-2 was smallest
(0.94 g/seed) and showed the least vigor. Bud take was similar for the
scions ‘Sunflower’ and ‘Susquehanna’ on all rootstocks. Twenty-one
weeks after budding, scions of ‘Sunflower’ were about 30% larger than
scions of ‘Susquehanna’; however, source of seedling rootstock did
not affect growth of either cultivar. Field evaluations have begun with
the two cultivars budded onto the six rootstocks.
POSTERS–TUESDAY
The Geneva® Apple Rootstock Breeding program initiated in 1968 by
Cummins and Aldwinckle of Cornell University and continued as a
joint breeding program with the USDA-ARS since 1998, has released a
new dwarf apple rootstock named Geneva® 41 or G.41. G.41 (a progeny
from a 1975 cross of ‘Malling 27’ × ‘Robusta 5’) is a selection that has
been tested at the N.Y. State Agricultural Experiment Station, in commercial orchards in the United States, and at research stations across the
United States, Canada, and France. G.41 is a fully dwarfing rootstock
with vigor similar to M.9 T337, but with less vigor than M.9 Pajam2.
It is highly resistant to fire blight and Phytophthora with no tree death
from these diseases in field trials or inoculated experiments. G.41 has
also shown tolerance to replant disease. Its precocity and productivity
have been exceptional, equaling M.9 in all trials and surpassing M.9 in
some trials. It also confers excellent fruit size and induces wide crotch
angles in the scion. It appears to be very winter hardy and showed no
damage following the test winter of 1994 in New York. Propagation
by layering in the stool bed G.41 is not consistent and may require
higher layering planting densities or tissue culture mother plants to
improve its rooting. G.41 also produces some side shoots in the stool
bed. The nursery liners of G.41 produce a smaller tree than G.16 liners, but similar to M.9, which is very acceptable. Unlike G.16, G.41 is
not sensitive to latent viruses. G.41 has similar graft union strength to
M.9 and requires a trellis or individual tree stake when planted in the
orchard. Suggested orchards planting densities with this rootstock are
2,000-4,000 trees/ha. This rootstock has been released for propagation
and commercial sale by licensed nurseries.
Kirk W. Pomper*, Sheri B. Crabtree
(317) Effects of Different Organic Mulch on Soil Physical
Characteristics and Leaf Nutrition in Apple Orchards
Hyun-Sug Choi*, Curt Rom, Jason McAfee
University of Arkansas, Horiculture, Fayetteville, AR, 72701
Mulch may affect soil chemistry, soil microclimate, biological communities, and tree performance. The trial was conducted to evaluate
the effects of different orchard mulches on leaf nutrition, soil moisture,
bulk density, root density, and water infiltration for understanding
potential use in organic orchards for weed control and as a nutrient
resource. Black plastic, hardwood chips, and shredded white paper were
applied to three apple cultivars, ‘Gala’, ‘Jonagold’, and ‘Braeburn’ on
M.9 rootstocks. A control was sprayed with contact herbicide. Trees
grown in hardwood mulch had the highest foliar P and K in year 3.
Trees in other mulches showed no difference of leaf nutrition in year
5. All treatments had consistently higher soil moisture than control in
year 1, 2, and 4. Mulch did not affect soil bulk density in year 2. The
root density was lowest under black plastic mulch in year 2, but was
similar in all treatments in year 3. In year 2, water infiltration was
fastest in hardwood mulch and control treatments.
(318) Influence of Orchard Site Parameters and Fruit
Distribution within Canopy on Fruit Quality of ‘Fuji’
Apple
Zlatko Cmelik*1, Stanislav Tojnko2
1
University of Zagreb, Department of Pomology, Svetosimunska 25, Zagreb, 10000, Croatia;
University of Maribor, Fruit Growing, Vrbanska 30, Maribor, 2000, Slovenia
2
Canopies of ‘Fuji’ apple trees, grafted on M.9 rootstock, planted in 1998
on two orchard sites at 2.8 × 0.7 m and trained as super spindles, were
subdivided in Spring 2003 into upper and lower parts. In each part, the
number of fruits, yield per tree, external (fruit size classes, and fruit
coloring), and internal (total sugar content, titratable acid content, and
flesh firmness) fruit quality attributes were determined. The orchard site
parameters affected growth, yield, and fruit quality in different ways.
The less suitable orchard site had less growth, lower yield per tree, and
a lower percentage of first class fruits, but most fruits had good color
(86% in top and 75% in lower part of canopy). The favorable orchard
site produced higher growth and yield, and a higher percentage of first
1027
6/20/05 5:01:25 PM
class fruits, but fruits had poorer color. In the lower part of the canopy,
fruits were of a good size, but had poor color. Fruits of the best quality
were obtained from the top part of the tree.
Poster Session 21—Computer Applications in
Horticultural Science
19 July 2005, 12:00–12:45 p.m. Poster Hall–Ballroom E/F
(357) GIS Tools for Documentation and Analysis of
Germplasm Collections from a Secondary Center of
Diversity: A Case Study for East African Sweetpotatoes
Arthur Villordon*1, Wambui Njuguna2, Simon Gichuki3,
Heneriko Kulembeka4, Jeremiah Simon4, Bernard Yada5,
Phinehas Tukamuhabwa5, Don LaBonte6
1
2
LSU AgCenter, Sweetpotato Research Station, Chase, LA, 71324; Kenyatta University,
School of Graduate Studies, Nairobi, Kenya; 3KARI, Biotechnology Centre, Nairobi, Kenya;
ARI-Ukiriguru, MAF Department of Research and Development, Mwanza, Tanzania;
5
Makerere University, Department of Crop Science, Kampala, Uganda; 6Louisiana State
University, Department of Horticulture, Baton Rouge, LA, 70803
4
The East African region in sub-Saharan Africa (SSA) is widely considered as one of the secondary centers of diversity for sweetpotatoes
[Ipomoea batatas (L.) Lam.]. Farmers in the region typically grow
landraces, but hybridizations occasionally result in new genotypes.
Factors such as regional conflicts, natural disasters, disease, and land
pressure continually threaten the SSA sweetpotato gene pool. Despite
this threat, very little updated information is easily accessible about
SSA germplasm collections. Such information is valuable for purposes
of management, exploration, and conservation. Using germplasm collection data from Kenya, Tanzania, and Uganda, we demonstrate how
publicly available GIS-based tools, e.g., DIVA-GIS, can be used to
document current collections as well as make this information easily
accessible, searchable, and portable. First, collection data from each
country were compiled and known collection sites were georeferenced
using available gazetteers. Following data cleaning and verification,
georeferenced data were then converted into a GIS-compliant format,
primarily as shapefiles. All files were then copied into storage media for
exchange among stakeholders. To further demonstrate the portability
of the GIS database files, available World Wide Web GIS web viewers
enabled real-time access to GIS files uploaded to an experimental web
site. This work demonstrates that with very little expense, access to
extant SSA germplasm information for sweetpotatoes can be improved
using publicly available GIS tools.
(358) A GIS Approach to Managing the Invasive Species
of Texas
William Spencer*1, Justin Williams2
1
Sam Houston State University, Agricultural Sciences, Huntsville, TX, 77340-2088; 2Sam
Houston State University, Biological Sciences, Huntsville, TX, 77340-2116
The state of Texas consists of roughly 4800 species of vascular
plants. In 1970, it was estimated that 200 of these were introduced
species. By 2003, the number of introduced species almost doubled
to 350. Using the Atlas of the Vascular Plants of Texas, a database
was compiled listing the invasive species in Texas and which of the
254 counties they inhabited. This database was then converted into
a GIS platform that allowed us to analyze those data spatially. With
these data, we were able to calculate the actual number of invasive
species per county. In addition, these data were used to predict possible
points of invasive species introduction, the rate of spread for certain
problematic species, routes of migration, and to isolate counties under
threat of possible infestation.
(359) Production of the Print-on-demand Publication
Weeds of Guam
James McConnell*, Mari Marutani, Robert Schlub, Lynn Rauler-
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final6_20July HS.indb 1028
son, Lauren Gutierrez, Gregoiro Perez
University of Guam, College of Natural and Applied Sciences, Mangilao, GU, 96923
This publication was produced with the goal of printing the booklet
on demand. The photographs were from multiple sources: scanned
film, digital photographs (camera), and digital photographs (flatbed
scanner). Fifty-six plants were included. Each plant was allocated
four half-letter-size pages (one double-sided letter). These four pages
include text descriptions of the plants and about nine images to give
the user information on habit, seed, fruit, inflorescence, flower, stem
characteristics, leaf pattern, pest damage, and other unique characteristics. Magnified images were used as necessary. The original digital
images were in either TIFF or RAW format. The final images were in
either TIFF or PSD format. Images were edited in Adobe Photoshop
and various plug-ins used to enhance the images to optimize color and
information that could be obtained from the printed image.
(360) Development of a Viticulture Website at Kentucky
State University for Growers
Sanjun Gu*, Kirk W. Pomper
Kentucky State University, Community Research Service, Frankfort, KY, 40601
Kentucky has a rich history in viticulture. The Kentucky Vineyard
Society was founded in 1798 and Kentucky was the third largest grape
and wine producer by 1860. During Prohibition, however, vines were
either uprooted or left unattended, and the grape industry essentially
disappeared in Kentucky. Since 1990, the grape and wine industry
has shown a resurgence; however, there are limited educational opportunities in viticulture in Kentucky. Kentucky State University
(KSU) emphasizes the development of alternative high-value crops for
sustainable agriculture production. In 2000, a viticulture program was
initiated at KSU to develop cultivar, vine management, and pest and
disease control recommendations. Aware of the fact that grape growers
in Kentucky are mostly new to grape culture, KSU has developed a
viticulture website (http://www.pawpaw.kysu.edu/viticulture/index.
htm) to disseminate viticulture information. The website provides
information that includes setting up a new vineyard, managing a
“mature” vineyard (Vitis, Kentucky weather and climate, site selection,
cultivars, rootstocks, trellising, care of young vines, canopy management, irrigation and nutrition, pest, and disease management), grape
growers’ corner (questions and answers, buy and sale, resources), and
selected links. A monthly viticulture calendar is also available. In the
future, the site will be updated with research results in viticulture
from KSU and other southeastern institutions, growers’ feedback,
and information on wine making. The viticulture website will aid in
the promotion of the grape and wine industry in Kentucky and states
with a similar climate, and benefit grape growers from this profitable
and expanding market.
(361) Public Domain Computer Programs for
Quantifying Size and Shape in Horticultural Research
Arthur Villordon*, Jason Franklin
LSU AgCenter, Sweetpotato Research Station, Chase, LA, 71324
Shape measurements in horticultural research have generally been
expressed as ratios or indexes. Computer-based image analysis enables
the objective quantification and statistical analysis of two-dimensional
sample shape variability. In addition, the availability of public domain
software facilitates the inexpensive but accurate quantification of object
shape in horticultural research. We describe the procedures for measuring sample shape using the following publicly available software:
ImageJ, ImageTool, and SHAPE. Using U.S. #1 sweetpotato storage
root samples from plots subjected to various weed control treatments,
we detected significant differences in elongation, compactness, as
well as shape attributes. We also measured size and shape variability
from representative fruit, leaf, and floral organ samples. The results
demonstrate that, where possible, measurement of two-dimensional
samples can be undertaken inexpensively and accurately using public
domain software applications.
HORTSCIENCE, VOL. 40(4), JULY 2005
6/20/05 5:01:27 PM
Poster Session 22—Postharvest Quality:
Cross-commodity
19 July 2005, 12:00–12:45 p.m. Poster Hall–Ballroom E/F
(38) Carbohydrate Content in Leaves of Three Poinsettia
Cultivars (Euphorbia pulcherrima) Grown at Two Locations
Maria-Teresa Colinas-Leon*1, Iran Alia-Tejacal2
1
Universidad Autonoma Chapingo, Department of Fitotecnia, Mexico-Texcoco, Chapingo,
Edo, 56230, Mexico; 2Universidad Autonoma del Estado de Morelos, Facultad de Ciencias
Agropecuarias, Domicilio Conocido, Cuernavaca, Morelos, 62210, Mexico
(39) Chlorine Dioxide Treatment Extends Longevity of
Cut Gerbera Flowers
Andrew J. Macnish*, Ria T. Leonard, Terril A. Nell
(41) Value-added Products from Agriculture: Sprouts
from Canola and Lupin Seeds
Harbans Bhardwaj*, Anwar Hamama
1
Virginia State University, Agricultural Research Station, Petersburg, VA, 23806
Sprouts from various seeds are considered healthy for human consumption. However, no information is available about sprouts made
from canola (Brassica napus L.) and white lupin (Lupinus albus L.),
two new potential alternate crops in the mid-Atlantic region of the
United States. Canola sprouts, on an average, contained (g/100 g, dry
weight basis) 38.9 oil, and 61.5, 18.6, 9.2, 7.4, 92.6, 64.8, and 27.8
percent of 18:1, 18:2, 18:3, total unsaturated, total saturated, MUFA,
and PUFA fatty acids, respectively, in the oil. Corresponding values
for white lupin sprouts were: 6.5, 43.0, 24.9, 9.3, 17.9, 82.1, 47.9, and
34.2. Canola sprouts contained 26.9% protein, whereas white lupin
sprouts contained 26.3% protein. Details of these experiments and
further results would be presented.
POSTERS–TUESDAY
In Mexico, poinsettia plants are grown under very different and changing environments, thus influencing their metabolism and changing the
sugar content that is important in leaf and bract longevity. In the present
study, the content of total soluble and reducing sugars and starch was
evaluated in leaves of three cultivars, ‘Marmol’, ‘Supjibi’, and V-17
‘Angelika’, in two contrasting environments: Cuautla, Morelos [24.6
°C, 74% relative humidity (RH), lat. 18°49’N; 1300 msl], and Texcoco,
Mexico (14.6 °C, 61.6% RH, lat. 19°31’N; 2310 msl). Plants were
grown under greenhouse conditions in 6-inch pots; the substrate and
cultural practices were similar in both locations. In Texcoco, plants
were covered with black plastic for 12 hours at night to control growth
and flowering initiation (15 Sept. to 12 Nov.). In Cuautla, this was
not necessary. Leaf samples were taken 8 days after initial covering
of plants in Texcoco (84 days after transplant) and 155 days after
transplant, when plants were ready for sale. Total soluble sugars were
reduced between 84 and 110 days after transplant in leaves of ‘Supjibi’
and ‘V-17’ cultivars independently of the location, while changes in
‘Marmol’ were minimal between days 84 and 155. Significant statistical
differences were found for leaf total soluble sugars between locations,
being higher in Cuautla, Morelos. For reducing sugars, no differences
were detected among cultivars and for the two locations.
(DC), which are amide derivatives of vanillylamine and 8-methyl6-nonenoic acid (E) or 8-methyl-nonanoic acid (A), respectively.
During our investigation of the mechanism of capsaicinoid-specific
metabolism in pepper fruit, we have developed a method to extract,
purify, and quantitate these fatty acids from the free fatty acid pool in
placental tissue. Fresh placenta was ground using a mortar and pestle
and extracted with diethyl ether. Fatty acids were methanolysed and
fatty acid methyl esters were quantitated using GC with capric acid
as internal standard. Capsaicinoids accumulated in the same placenta
were extracted with N,N-dimethylformamide (DMF) and quantitated
using HPLC. The lipid fraction had to be separated from capsaicinoids,
since capsaicinoids yielded about 10% of their respective fatty acids
during methanolysis. An aminopropyl column was used to separate
capsaicinoids from free fatty acids. Extraction recovery for both fatty
acids was greater than 70%.This procedure is being used to quantitate
fatty acid precursors for capsaicinoid biosynthesis in pepper placenta.
We will demonstrate use of this procedure with pepper selections varying in CAP/DC ratio to evaluate the effect of metabolic precursors on
capsaicinoid metabolism.
University of Florida, Environmental Horticulture, Gainesville, FL, 32611
The vase life of many cut flowers is often limited by bacterial occlusion
of stem bases. In this study, we tested the efficacy of a novel antimicrobial agent, aqueous chlorine dioxide (ClO2), to extend the longevity of
cut Gerbera flowers by reducing the number of bacteria in vase water.
Commercially mature and freshly cut Gerbera jamesonii ‘Monarck’
flowers were placed into clean vases containing deionized water and
0, 2, 5, 10, 20, and 50 μL·L-1 ClO2. Stems were then maintained in
solutions at 21 ± 0.5 °C and 42 ± 11% relative humidity until the end
of vase life. Inclusion of 2, 5, and 10 μL·L-1 ClO2 in vase water had
beneficial effects on flower longevity. For instance, treatment with 5
and 10 μL·L-1 ClO2 extended flower longevity by 1.4-fold or 3.7 days,
as compared to control flowers (0 μL·L-1 ClO2). In contrast, exposure
to the higher concentrations of 20 and 50 μL·L-1 ClO2 did not extend
flower vase life. Relative to control flowers, treatment with 10 μL·L-1
ClO2 delayed the onset of detectable bacterial colonization of vase
solutions from day 3 to day 6 of vase life. However, this ClO2 treatment
did not reduce the number of bacteria that subsequently accumulated in
vase water as compared to control flowers. Treatment with 10 μL·L-1
ClO2 also increased rates of solution uptake by stems and reduced
the loss of flower fresh weight over time. These results highlight the
potential use of ClO2 treatments to extend the postharvest longevity
of Gerbera flowers.
(40) A Procedure for Quantitation of Fatty Acid
Precursors in Relation to Capsaicinoid Accumulation in
Pepper Fruits
Janakiraman Maruthavanan*, Niels Maness, Donna Chrz
Oklahoma State University, Horticulture & LA, Stillwater, OK, 74078
The pungency in hot peppers [Capsicum annuum (L.) var. annuum] is
mostly due to two capsaicinoids, capsaicin (CAP) and dihydrocapsaicin
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(42) Sun Exposures Impact the Postharvest Quality and
Firmness of Harvested Bell Peppers
Maria Dolores Muy-Rangel1, Marita Cantwell*2
1
Centro de Investigaciones en Alimentacion y Desarrollo, A.C., Dept. Postharvest Technology, Carretera Culiacan-El Dorado, Sinaloa, 80129, Mexico; 2University of California,
Dept. Plant Sciences, Davis, CA, 95616
Temperature management of fresh products begins with proper handling at harvest. Inadvertent abuses, such as lengthy delays to cool
or exposure of harvested product to the sun, can detrimentally impact
postharvest quality. We used mature-green bell peppers to determine
the periods of sun exposure (midday during August in Davis, Calif.)
necessary to affect quality attributes (visual appearance, gloss, weight
loss, and firmness). Peppers were evaluated after cooling, storage at
7.5 °C for 3 or 7 days, and storage plus 2 days at 20 °C. The impacts
of sun exposure, although sometimes barely detectable after cooling,
became more noticeable once the peppers were stored. The additional transfer period to 20 °C after storage further accentuated the
impact of the exposure. Depending on the experiment, sun-exposed
areas reached 45 to 55 °C within 1 hour. Peppers typically lost 0.4%
to 0.5% and 1.0% to 1.3% weight during 1- and 2-hour exposures,
respectively. Changes in gloss and firmness (whole fruit compression
and pulp penetration) were preceded by changes in visual appearance.
Exposure to the sun for 0.5 hour did not impact postharvest quality of
peppers. Exposures from 1 to 1.5 hours usually resulted in changes
apparent only after the storage period. Such exposures are problematic
in commercial situations because these peppers are unlikely to be
eliminated during sorting on the packingline. Exposures of 1.5 to 2
hours usually resulted in an immediate change in appearance (pitting,
blistering, color change).
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6/20/05 5:01:28 PM
(43) Maturity Influences Lycopene Segregation during
Filtration Processing of Red-fleshed Watermelons
Ioannis P. Oikonomakos*1, Niels O. Maness1, Donna Chrz1,
William McGlynn1, Penelope Perkins-Veazie2
1
Oklahoma State University, Horticulture and Landscape Architecture, Stillwater, OK,
74075; 2USDA-ARS SCARL, South Central Agriculture Research Laboratory, Lane,
OK, 74555-0159
Lycopene from ground watermelon flesh can be segregated between
filtrate and filter cake by coarse filtration. Low speed centrifugation
of the filtrate can further segregate filtrate lycopene between an easily
recoverable precipitated high lycopene pellet and a serum. Lycopene
in watermelon flesh increases steadily during maturation and remains
constant, or slightly decreases in overripe melons. This study was
conducted to document the effect of melon maturity on lycopene segregation during filtration/centrifugal processing. Flesh of three seedless watermelon cultivars was ground and filtered through two layers
of Miracloth. Filter cakes were rinsed with water and filtrates were
centrifuged at 3500 g to precipitate lycopene. Centrifugal recovery of
lycopene from filtrates was about the same for undermature and mature
melons (50% to 70%), but was much lower for overripe melons (35% to
45%). This decline in recoverable lycopene from overripe melons could
be negated if ground flesh was heated to 60 or 85 °C prior to filtration.
Lycopene from preheated flesh segregated predominately into the filter
cake for all three maturity groupings. The interaction between melon
maturity and pre-filtration heating will be evaluated and integrated into
a potential watermelon lycopene production system.
(44) Postharvest Physiology and Quality of Pigeon Pea
[Cajanus cajan (L.) Millsp.]
Annette Wszelaki*1, Karla Deza-Duran2, Carol Harper3
1
University of Puerto Rico, Horticulture, Mayaguez, PR, 00681; 2University of Puerto Rico,
Food Science and Technology; 3University of Puerto Rico, Agricultural Engineering
Pigeon pea is an important food crop for the Puerto Rican diet, as well
as the economy. Pigeon pea ranks fourth in production among edible
legumes in production worldwide. It can be consumed dried or as a
vegetable (fresh, frozen, or canned). Canned, frozen, and dried peas
are commonly used when fresh peas are no longer available. Due to
the preferred flavor of fresh pigeon pea, it commands a higher market
premium, selling for more than twice the price of the dried product.
Although there is a great demand for this vegetable in Puerto Rico,
virtually no research has been done on fresh pigeon pea postharvest
physiology and its overall keeping quality. Baseline data on pigeon
pea physiology, including respiration and ethylene production rates,
soluble solids, titratable acidity, color reflectance, chlorophyll content,
and responses to ethylene are presented here in order to establish the
optimum storage temperature. Using this information, fresh pigeon pea
consumption could increase locally, and exporting opportunities for
shipping pigeon pea to alternative markets could be expanded.
(45) Effect of the Sugar : Acid Background on Perception
of Tomato Aroma
aroma. The sugar : acid ratio of the second tomato puree was found
to correlate with perception of taste descriptors sweet (+), sour (–),
bitter (–) (P < 0.05), and citrus (–) (P < 0.15) for most volatiles tested.
Correlations were also found for the sugar : acid ratio with overall
aftertaste (–) when the puree was spiked with furanol, trans-2-hexenal,
geranylacetone, or acetaldehyde; fruity (+) with β-ionone and linalool;
and tropical (+) with cis-3-hexenal and geranylacetone (P < 0.15). The
study suggests that increasing taste factors, like sweetness, result in
decreased perception of tomato aroma in general, and affect how aroma
compounds influence sensory descriptors.
(46) Foliar-applied Potassium: Effects on Muskmelon
Quality, Sugar, Ascorbic Acid, and Beta-carotene
Gene E. Lester*1, John L. Jifon2, Gordon Rogers3
1
Agricultural Research Service, U.S. Department of Agriculture, Weslaco, TX, 78596;
Texas A&M University, Horticulture, Weslaco, TX, 78596; 3University of Sydney, Food
and Natural Resources, John Woolly Building, Sydney, Australia
2
Muskmelon fruit [Cucumis melo L. (Retiulatus Goup)] sugar content
is related to potassium (K)-mediated phloem loading and unloading of
sucrose into the fruit. During fruit growth and maturation, soil fertility
is often inadequate (due to poor root uptake) to satisfy the demand for
K. Potassium uptake also competes with the uptake of Ca and Mg, two
essential minerals needed for melon fruit membrane structure, function
and postharvest shelf-life. Supplemental foliar-applied K could alleviate this problem especially during the critical fruit growth/maturation
period. We conducted experiments to determine the effects of timing
of supplemental foliar K applications on fruit quality and health attributes of orange-flesh muskmelon ‘Cruiser’. Plants were grown in a
greenhouse and fertilized with a regular soil-applied N–P–K fertilizer
throughout the study. Entire plants, including the fruit were sprayed
with a solution of a novel glycine amino acid-complexed potassium
(Potassium Metalosate, 24% K), diluted to 4.0 mL·L-1, 3 to 5 d after
anthesis (fruit set) and up to 3 to 5 d prior to abscission (full-slip). Three
sets of plants were either sprayed weekly, or bi-weekly or not sprayed
(control). Fruit from plants receiving supplemental foliar K matured on
average 2 days earlier, and had significantly higher fruit K concentrations,
soluble solids, total sugars, ascorbic acid (vitamin C), beta-carotene,
and were firmer than fruit from control plants. In general, there were
few differences in fruit quality aspects between bi-weekly or weekly
treatments. The data demonstrate that fruit quality and marketability
as well as some of the developmentally induced K deficiency effects
can be alleviated through foliar nutrition.
Poster Session 23—Vegetable Crops: Cultivar Evaluation
19 July 2005, 1:15–2:00 p.m.
Poster Hall–Ballroom E/F
(187) Zucchini and Yellow Squash Variety Evaluation
Results
Michelle L. Infante-Casella*1, Mel Henninger2
1
USDA/ARS, Citrus & Subtropical Products Laboratory, Winter Haven, FL, 33881
Rutgers Cooperative Extension, Agriculture and Resource Management Agents, Clayton, NJ, 08312; 2Rutgers The State University, Plant Biology and Plant Pathology, New
Brunswick, NJ, 08901-8520
Sugars (sucrose, glucose, fructose, or glucose/fructose in combination)
were added to coarsely chopped, deodorized tomato puree, increasing
the sugar level of the puree by 2% to 3%. Sugars (equal amounts of
glucose and fructose) along with citric acid were also added to another
puree, at two different levels, to create a range of sugar : acid ratios
(4.88–19.07). This second puree was then spiked with two different
levels of aroma volatiles, reported to affect tomato flavor, in order to
understand the influence of the sugar : acid background on tomato
aroma and taste perception. The tomato puree was presented to a trained
panel and was rated for intensity of aroma and taste descriptors on a
15-cm unstructured line scale. For the puree spiked with sugars only,
panelists detected differences for overall aroma, ripe aroma, overall
taste, sweetness and sourness intensities (P < 0.15). Adding sweet
sugars, like fructose and sucrose, resulted in decreased ratings for
aroma descriptors, apparently detracting from panelists’ perception of
Zucchini and straightneck yellow squash are important crops for
vegetable farmers. Variety choices change from year to year, based on
breeding programs that try to find disease tolerance or resistance by
developing new lines. A study was conducted at the Rutgers Agricultural
Research and Extension Center in Bridgeton, N.J., to determine yield
and quality of 14 zucchini, 6 yellow squash, and 5 specialty squash
varieties. Squash were seeded on 17 May 2004, at 30 inches between
holes into black plastic mulch on high raised beds. Rows were spaced
60 inches apart. Drip irrigation was used for supplying water and
fertigation. Prefar4E at a rate of 5 qt/acre applied on the soil surface
just before laying plastic was used for preemergent weed control. Five
days after planting, Sandea75WF at a rate of 1 oz/acre and Gramoxone
Max 3SC at a rate of 1.5 pt/acre were applied with a backpack sprayer
between the rows for added weed control. Admire was applied in the
seed hole at a rate of 24 oz/acre after planting using a backpack sprayer
Elizabeth Baldwin*, Kevin Goodner, Karen Pritchett
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for control of aphids and cucumber beetle. Harvests began on 22 June
2004, and were continued 3 times weekly for 5 weeks for a total of
15 harvests. Zucchini varieties ‘Revenue’, ‘Cashflow’, ‘Justice III’,
‘Spineless Beauty’, ‘Senator’, ‘HMX-2724’, and ‘EXT 04629728’
had statistically higher yields than did ‘Radiant’, ‘Wildcat’, ‘Payroll’,
‘HMX-2723’, ‘Lynx’, ‘Tigress’, and ‘Independence II’. Varieties are
listed in values from highest yielding to lowest yielding, respectively.
All yellow squash varieties had statistically similar yield values. These
included ‘General Patton’, ‘Cougar’, ‘Sunray’, ‘XPT1832’, ‘Goldbar’,
‘Sunbar’. Specialty varieties evaluated included ‘Zephyr’, ‘Starship’,
‘Magda’, ‘Flying Saucer’, and ‘Costata Romanesco’
(188) Evaluation of Edamame Cultivars in Central
Pennsylvania
Elsa Sánchez*, Kathleen Kelley, Lynn Butler
The Pennsylvania State University, Department of Horticulture, University Park, PA,
16802
Eight edamame [Glycine max (L.) Merrill] cultivars were evaluated
in the field in 2002, 2003, and 2004 to determine their suitability for
growing in central Pennsylvania. Each cultivar was direct seeded and
data collected included plant populations (percentage of stand) and
marketable yields. Plant populations ranged from less than 1% to 81%
and, with one exception in 2002, were below 80%. Eighty percent plant
populations or higher are considered optimal. Based on sub-optimal plant
populations, none of the edamame cultivars evaluated in the field were
determined to be suitable for direct seeding in central Pennsylvania.
The effect of temperature on seedling emergence, and therefore, plant
populations was then studied. Four of the edamame cultivars used in
the field trial were evaluated in growth chambers programmed with
varying day/night temperature regimes. Seedling emergence varied by
cultivar and was generally below 80% with two exceptions. When grown
in a 21.1 °C day/15.6 °C night temperature regime, ‘Butterbeans’ and
‘Early Hakucho’ exceeded 80% seedling emergence. These methods
could be used to produce transplants; however, the economic feasibility of doing so should first be evaluated. In the field trial, conclusions
on marketable yields were unattainable because soybean plants are
known to compensate in yield for plants missing in sub-optimal plant
populations. Plant compensation and sub-optimal plant populations
rendered yield comparisons between cultivars questionable. The issue
of sub-optimal seedling emergence and plant population needs to be
studied further before suitability of growing these edamame cultivars
in central Pennsylvania can be determined.
(189) Heirloom Tomato Cultivar Evaluations for the New
Jersey Market
Wesley Kline*1, Peter Nitzsche2
1
Rutgers University, Agricultural and Resource Management Agents, Rutgers Coop. Research and Extension, Millville, NJ, 08332; 2Rutgers University, Agricultural and Resource
Management Agents, Rutgers Coop. Research and Extension, Morristown, NJ, 07963
A 3-year study was established to evaluate a large number of heirloom
tomato cultivars for horticultural characteristics and yield. The initial
2001 screening included 110 cultivars with fruit types from currant to
beefsteak. The 110 cultivars were reduced to 12 (‘Arkansas Traveler’,
‘Box Car Willie’, ‘Brandywine Red’, ‘Carmello’, ‘Cherokee Purple’,
‘Costoluto Genovese’, ‘Eva Purple Ball’, ‘Hawaiian Pineapple’, ‘Mortgage Lifter’, ‘Prudens Purple’, ‘Ramapo’, and ‘Santa Clara Canner’)
based on yield, consumer preference and fruit characteristics and evaluated in 2004. The cultivars were arranged in a complete-block design
with plots of eight plants replicated four times. Fruits were harvested 10
times from 15 July to 16 Sept., graded into marketable and cull, counted,
and weighed. Internal and external fruit characteristics were evaluated
at the seventh harvest from 10 randomly selected marketable fruit from
three replications. Days to harvest from transplanting ranged from 61
to 82 days. For the early harvest (1–4), ‘Mortgage Lifter’ (20.18 t·ha-1)
and ‘Cherokee Purple’ (19.23 t·ha-1) had significantly more marketable
fruit than the other cultivars. By mid-season harvests (5–7), the cultivar
Carmello (43.38 t·ha-1) yielded statistically more marketable fruit than
all other cultivars. There were few differences among the cultivars
for the late harvest (8-10) period. When all harvests were combined,
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(190) Productive Behavior of Varieties with Different
Planting Densities in Okra [Hibiscus esculentus (L.)]
Cultivation with Controlled Irrigation
Francisco Radillo Juarez*, Juan Manuel González Gonzalez,
Marcelino Bazan Tene, J. Hyvan Castañeda Alvarez
Universidad de Colima, Facultad de Ciencias Biológicas y Agropecuarias, Tecomán,
Colima, 28100, México
Vegetables are important in Mexican agriculture because of the exportation opportunities made available by the opening of the Free Trade
Agreement. Okra represents a potentially profitable crop, and it is
important to understand its behavior in a predetermined environment,
and determine its optimal sowing density. The present work was realized to evaluate three genotypes and three densities of okra plants in
the production and quality of fresh fruit. The work was realized in the
winter–spring cycle in the dry tropic region, using a randomized block
design with a bifactorial of nine treatments. During the cultivation
cycle, the vegetative and productive variables did not present changes
in phenology, and only registered differences in plant height (58.4 and
57.6 cm., respectively) of PX 416543 and ‘Green Best’, with a distance
between plants of 18 cm. These results indicate that with increased
densities of 41,600, 50,000, and 69,444 plants/ha, there were no differences in the number and weight of fresh fruit/plant. Nevertheless,
with the production and support the quality of fresh fruit increased. We
conclude that high densities of plants increase the total crop of fresh
fruit per hectare without affecting quality. The variety PX 416543
presented the best vegetative and productive behavior.
POSTERS–TUESDAY
1
‘Carmello’ (76.59 t·ha-1) had significantly higher yields than the other
cultivars except ‘Mortgage Lifter’ (74.72 t·ha-1). External and internal
fruit characteristics varied among the various cultivars. All 12 cultivars
would be acceptable in different market segments.
(191) Vegetative and Productive Components of
Genotypes of Red Tomato (Lycopersicon esculentum Mill.)
under Greenhouse Conditions
Francisco Radillo Juarez*, Juan Manuel González Gonzalez,
Marcelino Bazan Tene, Luis Fernando Velasco Garcia
1
Universidad de Colima, Facultad de Ciencias Biológicas y Agropecuarias, Tecomán,
Colima, 28100, México
In world production of vegetables, the red tomato contributes 47% of the
total production and occupies second place in world consumption. The
objective of this research was to evaluate 13 genotypes of red tomato
with high technology for horticultural production in the greenhouse.
This study was realized in “Zamora” greenhouses in Quesería-Montitlán,
Colima, Mexico. The evaluated materials were: ‘Sun’, D-0289, D-2465,
D-2467, D-2475, D-2503, D-2505, D-2512, D-2515, D-2534, D-2541,
D-2552, D-7705, and, as control, the ‘Roman’ variety. The tallest height
was that of ‘Roman’ plants, 2.46 m, vs. the height of the first cluster of
fruits in D-2575 with 51 cm. With respect to largest number of fruits
per cluster and total harvested, D-0289 stood out with four and 18 fruits
per plant, respectively. In regard to fruit size, the genotypes D-0289 and
D-2534 presented the largest equatorial and polar diameter, with 19.2
and 14.2 cm, respectively. For fruit weight, the genotypes ‘Sun’ and
D-0289 presented the largest weight with 160 and 151 g, respectively.
We conclude that agronomic management influences production under
technical systems. For vegetative and productive desirable characteristics, the genotypes ‘Roman’, D-0289, and D-77055 were the more
adaptable for production in the greenhouse.
(192) Commercial Evaluation of Green Snap Bean
Varieties in Northwest Mexico
Raul Leonel Grijalva-Contreras*1, Rubén Macias-Duarte2,
Fabián Robles-Contreras3, Manuel de Jesus Valenzuela-Ruiz4
1
INIFAP-Caborca, Protected Horticulture, Caborca, Sonora, 83600, México; 2INIFAPCaborca, Soli & Horticultural; 3INIFAP-Caborca, Agroclimatology; 4INIFAP-Caborca,
Viticulture
Production of green snap beans is a good alternative for Caborca,
Sonora, Mexico. This vegetable can be harvested during the last week
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of November when market prices are good, and has good adaptation,
and high yield and pod quality. The objective of this experiment was to
evaluate 11 green snap bean varieties. This experiment was carried out
on a commercial field, where seed was sown on 25 Aug. 2003. Density
was 20 seeds/m (60 kg·ha-1). In this trial, we used a drip-irrigation
system on beds 2 m apart and two rows with 36 cm of separation per
bed. The first harvest was 68 days after the sowing date and lasted for
20 days, with four cuttings during that time. The varieties with greater
yield were ‘Castaño’, ‘Festina’, and ‘Landmark’ with 541, 494, and 463
boxes/ha (>30 pounds/box), respectively. The varieties with low yield
were ‘Espada’ and ‘Leader’ with only 52 and 75 boxes/ha, respectively.
The control ‘Savannah’ yielded 235 boxes/ha. The pod quality distribution was 20%, 35%, and 45% for first, second, and third classification,
respectively. ‘Savannah’ and ‘Festina’ had the best pod color (dark
green). None of the varieties evaluated had pest or disease problems.
(193) Yield and Quality of Six Bell Pepper Varieties in
Sonora, Mexico
Rubén Macias-Duarte1, Raul Leonel Grijalva-Contreras*2,
Fabián Robles-Contreras3, Manuel de Jesus Valenzuela-Ruiz1
1
INIFAP-Caborca, Soli & Horticultural, Caborca, Sonora, 83600, México; 2INIFAP-Caborca,
Protected Horticulture; 3INIFAP-Caborca, Agroclimatology
Bbell pepper (Capsicum annum L.) production is an appropriate
alternative for the northeastern Sonora, México (Magdalena River).
Because of the fresh temperature conditions of this region, production
is possible in spring and summer. However, it is necessary to have
appropriate varieties with a high potential for quality and yield under
these conditions. The objective of this research was to evaluate the
yield and quality of six varieties of bell pepper. The evaluation was
carried out at the INIFAP-CIRNO Experimental Station (Magdalena
of Kino, Sonora) in Spring 2002 under field conditions. The evaluated
varieties were: ‘Baron’, X3R Wisar, PS 236894, ‘Bamoa’, ‘Admiral’,
and ‘Navolato’. The date of seedling transplant was 29 Mar. in furrows
with 1 m of separation and 0.33 m between plants under a drip-irrigation
system. In the trials, we used a completely randomized design with
four replications. The measured variables were yield and fruit weight.
The harvest period was 26 June to 23 Aug. The results indicated that
the highest yields were obtained from: ‘Baron’, X3R Wisard, and PS
236894 with 43.2, 42.3, and 38.8 t·ha-1, respectively, and the lowest
yields obtained were from ‘Admiral’ and ‘Navolato’, with 33.3 and
30.0 t·ha-1, respectively. The highest fruit weights corresponded to PS
236894 and X3R Wisard with 145 and 140 g, respectively.
(194) Productivity and Quality of 14 “Saladette”-type
Tomato Varieties under Field Conditions
Rubén Macias-Duarte1, Raul Leonel Grijalva-Contreras*1,
Fabián Robles-Contreras1, Manuel de Jesus Valenzuela-Ruiz1
1
INIFAP-Caborca, Soli & Horticultural, Caborca, Sonora, 83600, México; 2INIFAPCaborca, Protected Horticulture; 3INIFAP-Caborca, Agroclimatology; 4INIFAP-Caborca,
Viticulture
In the north of Sonora, Mexico, it is possible to obtain high yields and
quality in “saladette”-type tomato production in two cycles, spring and
summer. However, seed varieties adapted to the temperature conditions
of these seasons that have a high potential for quality and yield are
needed. The objective of this experiment was to evaluate 14 varieties
of “saladette”-type tomato (indeterminate). The evaluation was carried
out in the INIFAP-CIRNO Experimental Station (Magdalena of Kino,
Sonora) in Spring–Summer 2002 under field conditions, in furrows 2
m apart and three plants per linear meter (15,150 plants/ha). The date
of seedling transplant was 29 May under a drip-irritation system. In the
trials, we used a completely randomized design with two replications.
We measured the yield, fruit weight, and shape. The harvest period was
from 20 Aug. to 30 Nov. The results indicated that the highest yields
were obtained from SSC-1020, ‘Brigade’, ‘Azteca’, ‘Purepecha’, and
‘Yaqui’ with 77.7, 74.8, 73.3, 71.8, and 69.7 t·ha-1, respectively. The
lowest yields corresponded to ‘Rio Grande’, ‘Silvestre’, and ‘Fierce Rio’
with 51.5, 50.4, and 36.9 t·ha-1, respectively. The highest fruit weights
were from ‘Purepecha’, SSC-1020, and ‘Yaqui’ with 109, 108, and 102
g, respectively. The fruit shape was oval-square in all varieties.
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Poster Session 24—Herbs, Spices, and Medicinals 1
19 July 2005, 1:15–2:00 p.m.
Poster Hall–Ballroom E/F
(388) Media Type and Moisture Influence Growth and
Development of Ginger (Zingiber officinalis) Propagules
Lurline Marsh*1, Corrie Cotton1, Elizabeth Philip1, Isoken Aighewi2
1
University of Maryland Eastern Shore, Agriculture, Princess Anne, MD, 21853; 2University
of Maryland Eastern Shore, Natural Sciences
Ginger (Zingiber officinalis) is a spice crop with a variety of medicinal
uses. Potentially, it may be suitable for ethnic production following
necessary studies to determine optimum cultural conditions. The propagation of ginger from rhizomes was investigated using three growth
media, three media moisture levels, and two types of propagules. The
media were poultry compost amended with peat and perlite in a volume
ratio of 2:1:1, municipal yard waste compost, and the commercial mix
Promix. The moisture levels of each medium were: no applied water,
moderately watered (between wilting point and field capacity), and field
capacity, which represented moisture tension levels of >–1.5, –0.08, and
–0.03 MPa, respectively. Growth from single-node rhizome propagules
and large pieces of 5.6 to 7.6 cm long with one or more nodes was
determined over 90 days. The large propagules and the field capacity
moisture regime produced the tallest shoots, and largest number of
shoots and leaves per propagule, as well as the highest percentages of
secondary rhizomes, root, and shoots per propagule. The yard waste
and Promix were superior to poultry compost in the development of the
propagules for all the traits measured. The large propagules produced
earlier shoot emergence at field capacity than at the moderate moisture
levels. Single-node propagules generally failed to emerge without applied moisture or when in poultry compost.
(389) Enhanced Growth in Acclimatization of In Vitro
Plantlets of Wasabi japonica using Hydroponics
Joo Hyun Lee, Yong-Beom Lee*, Kyu Sook Lee
University of Seoul, Environmental Horticulture, University of Seoul, Korea
Wasabi japonica plantlets were acclimatized in a hydroponic system
to determine effective procedures. The plantlets were cultured on
solid Murashige-Skoog medium with 3% sucrose. Shoots that formed
roots were transplanted into hydroponic systems: 1) acclimatization in
ebb-and-flow (EBB) for subirrigation (medium: granulated rockwool
and coir); and 2) acclimatization in deep flow technique (DFT). The
plantlets were acclimatized for 5 weeks under two irradiance treatments, 50 and 300 mmol·m-2·s-1. Photosynthetic capacity in high PPF
was higher than that in low PPF during acclimatization. Electron
transport rate from PS II (ETR) and biomass production increased
significantly with increased light availability. The fresh weight, dry
weight, and leaf area of plantlets in high PPF were higher than those in
low PPF. In particular, the dry weight and ETR of the plantlets grown
in high PPF increased more than twice as much as those in low PPF.
At 50 mmol·m-2·s-1 PPF, growth indexes, such as number of leaves,
leaf length, leaf width, leaf area, fresh weight, and dry weight, were
higher in EBB (granulated rockwool) > EBB (coir culture) > DFT.
At 300 mmol·m-2·s-1 PPF, those indexes were higher in DFT > EBB
(granulated rockwool) > EBB (coir). The Wasabi japonica plantlets
acclimatized in a hydroponic system also had a superior performance
when they were transferred to the field.
(390) Chemotype Variation among Black Cohosh
Populations
Hussein Al-Amier, Khaled A. Nasr, Lorna Lück, Lyle E. Craker*
1
University of Massachusetts, Medicinal Plant Program, Amherst, MA, 01003
Black cohosh [Actaea racemosa L.; syn. Cimicifuga racemosa (L.)
Nutt.] is a medicinal plant native to America and the woodlands of
eastern North America. The roots and rhizomes of black cohosh, used
by Native Americans to ease childbirth and treat menstrual cramps,
rheumatism, headaches, coughs, asthma, and snakebites, are currently
popular as an herbal remedy in the United States and Europe for the
HORTSCIENCE, VOL. 40(4), JULY 2005
6/20/05 5:01:32 PM
relief of discomfort associated with menopause. To determine chemical variation among populations of this perennial plant, root samples
from 33 locations within the natural range of the species, ranging from
Massachusetts to South Carolina and west to Missouri and Tennessee,
were collected and chemically analyzed by HPLC-PDA using a C-18
reversed phase column (Phenomenex) for separation of the chemical
constituents. The constituents were identified by comparison with commercial standards, including actein, methyl-beta-arabinopyranoside,
caffeic acid, cimicifugoside, cimicifugoside H1, cimiracemoside A, 26
deoxyactein, ferulic acid, isoferulic acid, kaempferol, formononetin,
and others. Chemically, an extract of the root and rhizome is known to
contain at least three major natural product groups: cycloartenal-type
triterpenes, phenolics, and flavonoids. Chemical constituents, especially
formononetin, varied among the populations.
Hyung Jun Kim1, Chris Harlow2, Mary Peet*2
1
National Horticultural Research Institute, Div. Protected Cultivation, Imok-Dong 475,
Gangan-Gu, Suwon, 440-706, Korea; 2North Carolina State University, Horticultural
Science, Raleigh, NC, 27695-7609
Rhizomes of black cohosh (Actaea racemosa L.) grown in the deep
woodland shade of eastern North America have been used historically
as medicinals, but wild populations have declined because of collection pressure. The purpose of this study is to determine the potential
for black cohosh production in perlite. Currently, cultivated plants
represent just 3% of the total harvest. Perlite production should also
result in clean, uniform plant material. Rhizomes were grown at 18
°C in controlled environment chambers in the North Carolina State
University (NCSU) Phytotron in perlite for 42 days with fertigation 3,
6, or 12 times daily and 18.5, 21.5, or 24.5 °C root zone temperatures
adjusted using heating cables. Leaf areas of the 21.5 and 24.5 °C root
temperature treatments were greater than the 18.5 °C treatment. Stem
number and new root number was highest in the 21.5 °C treatment.
No effects of the fertigation treatments were significant. The second
experiment was conducted 7 June–31 Oct. 2004 in a naturally lit temperature-controlled (22/18 °C) glass greenhouse in the NCSU Phytotron
at nutrient solution EC levels of 0.7, 1.1, or 1.5 dS·m-1 and shading
levels of 0%, 50%, and 75%. Highest leaf area and increase in fresh
weight of the rhizomes over the experimental period was in the 50%
shading treatment, but no significant effects of EC treatments were
observed. Rhizome fresh weight increased 310% in the 50% shade,
compared to 193% and 196% in the 0% and 75% shading treatments,
respectively. In conclusion, black cohosh appears to prefer some shading
during summer and 21.5 °C root temperatures. Low EC (0.7 dS·m-1)
and infrequent watering (3 times daily) did not appear to limit growth
in this system, but these results should be confirmed in larger studies
in commercial greenhouses.
(392) Effect of Bovine Manure Application to Soil on the
Development of Sabila Crops (Aloe vera barbadensis) in
the Sonoran Desert
Fabián Robles-Contreras1, Rubén Macias-Duarte2,
Raul Leonel Grijalva-Contreras*3,
Manuel de Jesus Valenzuela-Ruiz4
1
INIFAP-Caborca, Agroclimatology, Caborca, Sonora, 83600, México; 2INIFAP-Caborca,
Soli & Horticultural; 3INIFAP-Caborca, Protected Horticulture; 4INIFAP-Caborca,
Viticulture
The sabila plant is considered a strategic crop for the arid and semi-arid
lands of Mexico, because it can be a high water-efficient crop due to
its low water requirements, and is currently developing satisfactorily
on an experimental scale in the agricultural area of Caborca, Sonora,
Mexico, in the Sonoran Desert. This agricultural zone is characterized
by a sandy soil with little or no organic matter and limited water supplies. Research consisted of evaluating the effect of bovine manure
(BM) application to soil on the yield and size of sabila leaves. A sabila
planting was established in Summer 2002, with a density of 15,000
plants/ha. Two applications of BM (9 t·ha-1) were made, one at planting
time in Aug. 2002, and another one in Feb. 2003. BM was not applied
HORTSCIENCE, VOL. 40(4), JULY 2005
final6_20July HS.indb 1033
(393) Diversifying Into a New Market—Medicinal Herbs
Jeanine M. Davis*, Jacqulyn T. Greenfield
1
North Carolina State University, Horticultural Science, Mountain Horticultural Crops
Research and Extension Center, Fletcher, NC, 28732; 2Gaia Herbs, Inc., Botanicals Division, Brevard, NC, 28712
Seventeen North Carolina farmers received $5000 grants to grow
medicinal herbs as part of a research study to determine the economic
feasibility of producing herbs in different regions of the state, including
producing the quality and quantity of medicinal herbs required by the
industry at a price that is competitive in a global market. With the help
of five buyers in the natural products industry, four medicinal herbs
were selected to be grown: California poppy, dandelion, Echinacea
purpurea, and valerian. The growers experimented with new crops,
learned new production methods, and adapted existing methods and
equipment to these crops. These growers were also introduced to new
markets and made connections with buyers, statewide and nationally,
in an industry that can be difficult to enter. Growers were responsible
for keeping detailed records of production, harvest, and postharvest
handling. To produce a marketable crop in 1 year, some of the growers
started seedlings in their greenhouses, while others direct seeded into
the field. With the natural products industry moving toward a nonchemically grown product, growers in this project had to produce their
crop without pesticides. Weed pressures were the biggest challenge
to most of the growers. Prior to harvest, bioactive constituents were
tested on the dried raw material to see if levels met buyers’ requirements. Other testing methods determined percentage of ash, moisture
content, microbial limits, and heavy metal accumulation. For postharvest
handling, tobacco farmers who had drying facilities experimented with
different temperature regimes to produce a uniformed dried material.
Buyers and growers were then introduced to each other to complete
the sale of goods.
POSTERS–TUESDAY
(391) Black Cohosh (Actaea racemosa L.) Propagation and
Growth in Perlite Hydroponic Systems
to the control treatment. Although the harvest of leaves initiated in
Dec. 2003 (plant formation), the first commercial harvest was made
in Jan. 2005. We measured the yield and the average weight of leaves.
The results indicated statistical differences (0.05) and an increase in
the yield of 12.2 t·ha-1, which represents 26% more with the BM application with respect to the control, which produced 47.1 t·ha-1. As far
as the average weight of leaves, there were no statistical differences
between the BM application (597 g) and the control (532 g), although
in both cases, they met the standards demanded by companies that
manufacture products with sabila.
(394) Antimutagenicity, Antioxidant Activity, and
Polyphenolic Contents of Bitter Melon Varieties
(Momordica charantia L.)
Shahidul Islam*1, M. Jalaluddin1, Navam Hettiarachchy2
1
University of Arkansas, Agriculture (Plant Physiology & Nutrition), Pine Bluff, AR, 71601;
University of Arkansas, Food Science, Fayetteville, AR 72701
2
Bitter melon (Momordica charantia L.), an annual vegetable of
Cucurbitaceae family, is a vegetable with important nutritional and
medicinal qualities. Four adaptable lines/varieties were tested in
replicated field trials for productivity, and biochemical and medicinal
characteristics at the University of Arkansas at Pine Bluff. The total
phenolic contents of the oven-dried and freeze-dried tissues, and seeds,
ranged from 5.39–7.75, 6.72–8.02, 6.40–8.90, and 4.67–6.69 mg·g-1
on a dry weight basis, respectively. The total phenolic content of bitter
melon from India green (IG), India white (IW), China green (CG) and
China white (CW) varieties were 4.67–6.72, 6.03–8.02, 5.39–7.81, and
6.69–8.90 mg·g-1 dry material, respectively. The main phenolic acids in
bitter melon flesh were gallic acid, gentisic acid, catechin, chlorogenic
acid, and epicatechin. Bitter melon seeds had the phenolic acids, gallic
acid, catechin, and epicatechin. The antioxidant activities of methanolic
extracts from the bitter melons varieties IG, IW, CG, and CW ranged
from 79% to 85%, 79% to 83, 80% to 85, and 79% to 86% inhibition,
respectively. The antioxidant activities of the seed ranged from 79%
to 84% inhibition. Methanolic extracts of freeze-dried flesh and seed
from var. IW and CG showed very high antimutagenic effects against
benzo(a)pyrene with Salmonella TA98 (92% to 100% inhibition) TA100
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6/20/05 5:01:33 PM
(79% to 86% inhibition), but lower antimutagenicity activities against
sodium azide that ranged from 46% to 54% and 17% to 32% inhibition,
respectively. The popular belief that bitter melon improves glucose
tolerance in Type II diabetes and lowers blood cholesterol is being
investigated. It has not been determined which alkaloids, polypeptides,
or combination of chemicals found in bitter melon are responsible for
the beneficial medicinal effect.
(395) Greater Inoculation Rate Enhances Biological
Efficiency and Returns of Shiitake Mushrooms
Cathy M. Sabota*, Caula A. Beyl
Alabama A&M University, Plant and Soil Science, Normal, AL, 35762
To determine if biological efficiency of shiitake mushrooms was affected
by the density of spawn inoculation, white oak logs about 31 inches
(0.79 m) long were cut from trees harvested 14 Apr. and inoculated 6
May 2003 with strain WR46 of Lentinula edodes using four rates of
inoculation. The number of holes drilled and inoculated with spawn was
determined by multiplying the weight of each log by 0.5, 1, 2, or 3. A
15-pound log (6.8 kg) inoculated at “3” times the weight would have
45 holes drilled and inoculated. Each rate of inoculation treatment was
replicated three times with three subsamples per replication. After six
harvests over a 21-month period, the biological efficiency (BE) of the
logs increased by 1.94% per additional hole per pound (0.45 kg). This
increase in BE would result in $1.15 in additional returns per log with a
cost of only $0.15 more per log due to increased spawn use, resulting in
a net profit, excluding increased labor and wax costs, of $1.00 per log.
(396) Growth of American Mayapple Rhizome Segments
Affected by Time of Transplant
Kent Cushman*, Muhammad Maqbool
University of Florida, SWFREC, Immokalee, FL, 34142-9515
American mayapple (Podophyllum peltatum) is being investigated as
a domestic, renewable, and alternative source of podophyllotoxin, a
precursor compound used in the manufacture of several drugs. Indian
mayapple (P. emodi) is the current source of the compound. The objective of this study was to examine growth of transplanted rhizome
segments of American mayapple at four transplant times during the
year. Two-node rhizome segments were carefully dug with roots intact
from naturally occurring wild populations near Holly Springs, Miss.
Segments were dug in Oct. 2002, Dec. 2002, Feb. 2003, or June 2003.
Within 1 day of each harvest, segments were transplanted into 1-gal
pots containing a mixture of sandy soil and a finely ground pine bark
mulch. Pots were then set in a raised bed, such that the soil surface
within the pots was even with that of the plant bed. Pots and plant bed
then received a 3-inch layer of pine bark mulch. Rhizome segments
were harvested from pots four times during the year following the date
of transplant. Rhizome and roots were separated according to new or
old growth and then dried. Rhizome segments transplanted during
October and December increased about 36% in dry mass during the
1-year period after transplant. This was significantly greater than an
increase of 12% for segments transplanted during June. Segments
transplanted during February performed intermediately, increasing by
22%. Our results show that rhizome segments of American mayapple
performed better when transplanted during fall and winter compared
to those transplanted during summer. Segments transplanted during
spring performed intermediately.
(397) Atypical Disease Response to Hop Powdery Mildew
Jodi M. Smith*1, Kim E. Hummer2, Walt Mahaffee3
1
Oregon State University, Horticulture, Agricultural Life Science Building, Corvallis, OR,
97331; 2USDA ARS, National Clonal Germplasm Repository, Corvallis, OR, 97333-2521;
3
USDA ARS, HCRL, Corvallis, OR, 97330
Open-pollinated hop seeds (Humulus lupulus var. lupuloides E. Small,
H.l. var. pubescens E. Small, H.l. var. neomexicanus Nelson and Cockerell, and H.l. var. lupulus L.) were collected from the United States,
Canada, and Kazakhstan and screened for resistance to hop powdery
mildew (Podosphaera macularis Braun & Takamatus). A total of 2108
seedlings were repeatedly inoculated with high levels of P. macularis.
Under greenhouse conditions, most seedlings exhibited a compatible
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final6_20July HS.indb 1034
disease response typical of susceptible hosts with sporulating colonies
covering both leaf surfaces. Three genotypes from hop seed native to
Emba, Kazakhstan, remained uninfected in greenhouse assays. Further
experimentation of those genotypes in growth chambers at 18 °C revealed
that they demonstrated an atypical disease response. Six days after
inoculation, necrotic lesions on the adaxial leaf surfaces were visually
apparent. Microscopic examination showed areas of collapsed epidermal
cells, collapsed hyphae, and golden-brown discolorations extending
out from the center of the infection. These symptoms contrasted those
of a hypersensitive response in which fungal growth is restricted by
the collapse of epidermal cells in advance of the fungus. The infection
frequency of Kazakhstani genotypes was intermediate compared to H.l.
cultivars Symphony (susceptible) and Nugget (resistant) after exposure
to three preinoculation temperature regimes. These genotypes could represent a new source of polygenic resistance to hop powdery mildew, and
could broaden hop germplasm available to global breeding programs.
Poster Session 25—Stress Physiology
19 July 2005, 1:15–2:00 p.m.
Poster Hall–Ballroom E/F
(445) Responses of Several Herbaceous Perennials and
Groundcovers to Salinity
Genhua Niu*, Denise S. Rodriguez
Texas A&M University, El Paso, TX, 799277
In order to use reclaimed water to irrigate landscape plants and minimize
damage and loss, salinity tolerance of commonly used landscape plants
needs to be identified and characterized. Eight herbaceous perennials
and groundcovers were obtained from a nursery, transplanted to 2.6-L
plastic containers, and grown in the greenhouse for 2 weeks before
salinity treatments (1.0, 3.2, 6.4, and 12 dS·m-1) were initiated. Plants
were irrigated with measured amounts of saline solutions to obtain a
30% leaching when ≈50% water was depleted. After 12 weeks, half
of the plants in each treatment were destructively harvested and dry
weights of shoots and roots were taken. Three Penstemon species
(pseudospectabilis, eatoni, and strictus) and Lavandula angustifolia at
6.4 and 12 dS·m-1 and most of them at 3.2 dS/m did not survive. Shoot
dry weight of Delosperma cooperi decreased by 25% at 12 dS·m-1, but
there were no significant differences among the rest of the treatments.
All plants of Teucrium chamaedrys survived, but growth was reduced
significantly with lower visual scores as salinity of irrigation water
increased. Although growth was reduced in Gazania rigens as salinity increased, no other signs of stress were observed. Ceratostigma
plumbaginoides had less growth at 3.2 dS·m-1, and older leaves showed
reddish pigmentation at 6.4 dS·m-1, whereas those at 12 dS·m-1 did not
survive. Among the tested species, D. cooperi and G. rigens indicated
a high tolerance to salinity; T. chamaedrys and C. plumbaginoides were
moderately tolerant; and the rest were salt sensitive.
(446) Salinity Tolerance of Eight Ornamental Herbaceous
Perennials
Nickolee Zollinger*1, Teresa Cerny-Koenig2, Roger Kjelgren1,
Rich Koenig3, Kelly Kopp1
1
Utah State University, Plants, Soils, & Biometeorology, Logan, UT; 2Washington State
University, Plants, Soils, & Biometeorology; 3Washington State University, Agronomy,
Pullman
Although salinity is becoming an increasing concern for landscape
plants in many areas of the West, few studies have been carried out to
evaluate salinity responses of ornamental plants, especially herbaceous
perennials. We investigated salinity tolerance of four traditionally grown
and four Intermountain West native ornamental herbaceous perennials.
Penstemon ×mexicali ‘Red Rocks’, Leucanthemum ×superbum ‘Alaska’,
Echinacea purpurea, Lavandula angustifolia, Geranium viscosissimum,
Eriogonum jamesii, Penstemon palmeri, and Mirabilis multiflora were
irrigated with water containing a mixture of 2 CaCl2 : 1 NaCl at salinity
levels of 0.33 (tap water control), 2.2, 5.4, and 8.3 dS·m-1 for 8 weeks.
Growth, visual quality, and gas exchange were assessed. Mirabilis
multiflora and L. ×superbum ‘Alaska’ showed high salt tolerance based
HORTSCIENCE, VOL. 40(4), JULY 2005
6/20/05 5:01:35 PM
on visual quality. No noticeable leaf necrosis was observed for either
species at any salinity level. However, over the 8-week period, growth
rates for L. superbum were reduced by 35%, 58%, and 72% compared
to the control for the 2.2, 5.4, and 8.3 dS·m-1 salinity levels, respectively.
The decrease in growth did not reduce visual quality. Growth rates for
M. multiflora were slightly higher than the control for the 2.2 and 5.4
dS·m-1 salinity levels and dropped about 20% at the highest salinity
level. Echinacea purpurea showed the lowest tolerance to salinity, as
evidenced by substantial margin burn at all salinity levels as well as high
mortality; all plants in the highest salinity treatment died.
(447) Response of Two Salt-stressed Cultivars of Sweetpotato
to Changes in Calcium Levels under In Vitro Conditions
Devi Prasad V. Potluri*, Nkechiyere Nwami
Chicago State University, Biological Sciences, Chicago, IL, 60628
(448) Arbuscular Mycorrhizal Fungi Enhance Tolerance of
Rosa multiflora cv. Burr to Bicarbonate in Irrigation Water
Andrew D. Cartmill*, Fred T. Davies, Jr., Alejandro Alarcon,
Luis A. Valdez-Aguilar
Texas A&M University, Horticultural Sciences, Dept. Horticultural Sciences, College
Station, TX, 77843-2133
Sustainable horticultural production will increasingly have to rely on
economically feasible and environmentally sound solutions to problems
associated with high levels of bicarbonate (HCO3-) and associated high
pH in irrigation water. The ability of arbuscular mycorrhizal fungi (AMF;
Glomus ZAC-19) to enhance plant tolerance to HCO3- was tested on
the growth, physiology and nutrient uptake of Rosa multiflora Thunb.
ex J. Murr. cv. Burr (rose). Arbuscular mycorrhizal colonized and noninoculated (non-AMF) plants were treated with 0, 2.5, 5, and 10 mM
HCO3-. Increasing HCO3- concentration and associated high pH and
electrical conductivity (EC) reduced plant growth, leaf elemental uptake
and acid phosphatase activity (ACP), while increasing alkaline phosphatase activity (ALP). Inoculation with AMF enhanced plant tolerance
to HCO3- as indicated by greater plant growth, leaf elemental uptake
(N, P, K, Ca, Fe, Zn, Al, Bo), leaf chlorophyll content, higher mycorrhizal inoculation effect (MIE), lower root iron reductase activity, and
generally lower wall-bound ACP (at 2.5 mM HCO3-), and higher soluble
ALP (at 10 mM HCO3-). While AMF colonization (arbuscules, vesicles,
and hyphae formation) was reduced by increasing HCO3- concentration,
colonization still occurred at high HCO3-. At 2.5 mM HCO3-, AMF plant
growth was comparable to plants at 0 mM HCO3-, further indicating the
beneficial effect of AMF for alleviation of HCO3- stress.
(449) Influence of Irrigation Frequency on Establishment
and Growth of Ilex cornuta ‘Burfordii Nana’ and
Viburnum odoratissimum in Landscapes
1
2
2
Sloane M. Scheiber , Maria Paz* , Edward F. Gilman ,
Kimberly A. Moore3, Sudeep Vyapari4, Richard C. Beeson, Jr.1
1
University of Florida, Environmental Horticulture, Apopka, FL, 32703; 2University of
HORTSCIENCE, VOL. 40(4), JULY 2005
final6_20July HS.indb 1035
Landscape water consumption has become a prime target for water conservation and regulation. Imposing water restrictions during landscape
establishment is detrimental to plants that have not developed sufficient
root systems to compensate for transpirational water losses. Generally,
municipalities regulate irrigation frequency but not application rate.
Application frequency affects establishment rates of shade trees, but
the effects on shrub establishment are not well documented. This study
evaluated three irrigation frequencies during establishment of Ilex
cornuta ‘Burfordii Nana’ and Viburnum odoratissimum in a landscape.
To simulate maximum stress, both species were transplanted into field
plots in an open-sided, clear polyethylene covered shelter. Each species
was irrigated either every 2, 4, or 7 days, and received 9 L of water
per plant per event. Predawn, midday, and dusk water potentials were
recorded at 28-day intervals and cumulative stress intervals calculated.
Water potentials were taken the day prior to irrigation (maximum stress
day) and the day of irrigation (minimum stress). Growth indices were
also recorded. As days after transplant (DAT) increased, significant
declines in cumulative water stress of Ilex were found among treatments on the day of maximum stress. The 7-day treatment declined
at a faster rate than the other treatments tested. No differences were
found for Viburnum. No significant differences were found on the day
of irrigation as DAT increased. Differences in canopy size were not
significant among treatments for either species.
(450) Drought Responses of Ornamental Herbaceous
Perennials
POSTERS–TUESDAY
Two cultivars of sweetpotato, ‘Commensal’ and ‘Salyboro’, were subjected to salt stress using axillary bud cultures. The salt levels ranged
from 0 to 10 g·L-1. After the initial experiments, levels of calcium in
the medium were changed from 3 mM in the MS medium to 1.5, 6, and
12 mM. After 10 weeks of growth, plantlet shoot height, dry weight,
number of nodes, levels of proline, soluble carbohydrate, and protein
were measured. ‘Commensal’ was tolerant to salt levels up to 4 g·L-1,
but ‘Salyboro’ was sensitive to concentrations of salt even at lower
concentrations as evidenced by the growth and dry weight. Proline
accumulation was higher in the shoot than in the root. The protein :
carbohydrate ratios did not change much in ‘Commensal’, but levels
of carbohydrates increased in ‘Salyboro’. Reduction in calcium levels
had a synergistic affect on salt-stressed cultivars. Enhanced levels of
calcium reduced the inhibitory affects of salt stress. This was more
pronounced in ‘Salyboro’, which was susceptible. Proline levels were
higher in plants subjected to salt stress and higher levels of calcium than
controls, but lower than the plants subjected to salt stress. These and
other metabolic changes suggest that calcium can reduce the adverse
affects of salt stress in these two sweetpotato cultivars.
Florida, Environmental Horticulture, Gainesville, FL, 32611; 3University of Florida, Environmental Horticulture, Ft. Lauderdale, FL, 33314; 4University of Florida, Environmental
Horticulture, Plant City, FL, 33566
Nickolee Z*1, Roger Kjelgren1, Teresa Cerny-Koenig2,
Rich Koenig3, Kelly Kopp1
1
Utah State University, Plants, Soils, and Biometeorology, Logan, UT, 84322; 2Washington
State University, Horticulture; 3Washington State University, Agronomy
We investigated drought responses of Echinacea purpurea, Gaillardia
aristata, Lavandula angustifolia, Leucanthemum ×superbum ‘Alaska’,
Penstemon barbatus ‘Rondo’, and Penstemon ×mexicali ‘Red Rocks’
established in a 10-gal pot-in-pot system in northern Utah. Plants were
irrigated at frequencies of 1, 2, or 4 weeks between June and Sept.
2004. Osmotic potential, gas exchange, visual quality, leaf area, and
dry biomass were assessed. In a confined root zone, P. barbatus showed
the greatest tolerance to drought, avoiding desiccation by increasing
root : shoot ratio and decreasing transpiration as water became more
limiting. Plants maintained high visual quality throughout the study
and experienced little wilt, burn, or dieback. However, P. barbatus
above-ground biomass was reduced by 15% for the 2-week treatment
and by 40% for the 4-week treatment. Alternatively, G. aristata and L.
superbum displayed drought avoidance mechanisms, dying back when
water was limiting and resprouting after they were watered. Aboveground biomass declined by 50% and 84% for G. aristata and 47% and
99% for L. superbum, respectively, for the 2- and 4-week treatments.
Root mass was affected similarly for both species. However, transpiration remained high for all treatment levels. Leaf burn and reduction in
above- and below-ground biomass were also evident for E. purpurea
at the 2- and 4-week treatments, but results were not as pronounced
as for G. aristata and L. superbum. Overall, P. barbatus exhibited the
greatest drought tolerance while maintaining an acceptable appearance.
G. aristata, contrary to expectations, did not exhibit drought tolerance
with a confined rooting volume, suggesting that it avoids drought in
landscapes by means of deep rooting.
(451) Acclimation to Long-term Water Deficit Stress in Four
Birch Taxa (Betula L.): Water Relations and Gas Exchange
Mengmeng Gu*1, Curt R. Rom1, James A. Robbins2
1
University of Arkansas, Dept. of Horticulture, Fayetteville, AR, 72701; 2University of Arkansas, Cooperative Extension Service, Department of Horticulture, Little Rock, AR, 72203
Four birch taxa, Betula alleghaniensis, B. davurica, B. nigra ‘Heritage’,
and B. papyrifera, were grown in a greenhouse and exposed to water
deficit stress for 35 days. Daily water was withheld from the plants until
the combined weight of each container and the plant was reduced to 40%
of the control. Supplemental water was supplied to each container to
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6/20/05 5:01:36 PM
maintain 40% of the initial combined weight. Predawn water potential,
gas exchange, and abscised leaf area were measured daily during the
first week and at 3-day intervals after the first week. Predawn water
potential dropped to lowest value before the containers were rehydrated
and remained low throughout the treatment period. Net CO2 assimilation
(A), stomatal conductance (gs) and evapotranspiration (Et) of all taxa
decreased significantly during the first week of water deficits. Changes
in A and Et varied among taxa after the first week of water deficits.
Water use efficiency (WUE = A/Et) of four birch taxa decreased to
significant lower values than control in the first week that water was
withheld, and then increased to significantly higher values than control.
Gas exchange data were fit into 2- or 3-segmented linear model. The
type and shape of the models, and the joint of each segment gave an
indication of how the gas exchange responded to the long-term water
deficit stress. At the end of the water deficit treatment, B. papyrifera had
abscised most of its leaves and maintained a high A, while B. alleghaniensis maintained more leaves on the tree, but had a relatively low A.
(452) Growth Responses of Salvia greggii and Dalea
frutescens to Drought Stress
Genhua Niu*, Denise S. Rodriguez
Texas A&M University, El Paso, TX, 79927
Salvia greggii (salvia) and Dalea frutescens (dalea) are two popular
shrubs. However, little information is available on their drought tolerance. The objectives of this study were to investigate the effect of various
degrees of water stress on growth and to characterize the dynamics of
water relations to root substrate water content for developing best irrigation management. Salvia and dalea plants in 12-L plastic containers
were grown in a greenhouse and pruned to one node at the base of the
soft shoots for salvia or at the same height for dalea prior to the start
of the experiment. There were three irrigation regimens: plants were
irrigated daily (control), or irrigation was withheld until moderate or
severe water stress signs exhibited. After several weeks of intermittent
cyclic dry-down irrigation regimens, total shoot number per container
was reduced by 40% to 50% for salvia and 35% to 40% for dalea. Average
shoot length was reduced by 35% to 45% for salvia and 50% to 65%
for dalea in moderate and severe stressed treatments compared to the
control. Drought stress resulted in less shoot elongation and fewer new
shoots in both species. To examine the relationship between plant water
status and substrate water content, a dry down test was performed on
five well-watered plants by withholding irrigation until midday water
potential dropped to below –4 MPa. As substrate water contents in both
species reached 8%, the predawn water potentials did not recover from
the midday water potential of the previous day, indicating there was no
available water in the substrate for roots to take up. The drought tolerance
of these two species needs further study using various growing media.
(453) Effect of Drought Stress on Growth and Secondary
Compound Production in Greenhouse-grown Guayule
Maren E. Veatch-Blohm*, Dennis T. Ray
1
University of Arizona, Plant Sciences, Tucson, AZ, 85721
As a native of the Chihuahuan desert, guayule (Parthenium argentatum
Gray) has a history of dealing with low water availability. Agronomic
studies have shown that increasing irrigation increases overall rubber
yields, but decreases rubber concentration per plant. As water availability is an important factor in agricultural production, this study was
conducted to examine how drought affects plant growth and secondary
compound distribution throughout the plant. One-year-old guayule
plants were subjected to water stress from June through August, in
2003 and 2004. The well-watered treatment was irrigated daily, and
the drought-stressed plants were irrigated when the soil water potential reached 6 (0.6) or 3 (0.3) bars (megapascals) in 2003 and 2004,
respectively. Plant growth was monitored by measuring height, width,
and stem diameter. Fresh weight of shoots and roots was recorded at
harvest, and a subset of plants were defoliated and used to determine
leaf weight and area. Resin and rubber were extracted from dried and
ground plant samples. Growth, leaf weight, and leaf to stem ratio were
decreased in the drought-stressed plants compared to the well-watered
plants. Rubber concentration, but not resin concentration, was higher
1036
final6_20July HS.indb 1036
in the drought-stressed plants. There were no significant differences
in resin and rubber concentration in the leaves and roots of the different treatments; however, they were both higher in the stems of the
drought-stressed plants. In guayule, rubber is deposited mainly in the
bark parenchyma of the stems. The drought-stressed plants had a greater
contribution of stem biomass to overall biomass and a reduced stem
diameter with higher bark to wood ratio, which could account for the
higher rubber concentration in the drought-stressed plants.
(454) Detecting Plant Stress by Chlorophyll Fluorescence
Hussein Al-Amier1, Robert Lussier2, Ming Coler1,
Margaret Stoltzman1, Lyle Craker*1
1
University of Massachusetts, Plant and Soil Sciences, Amherst, MA, 01003; 2GrowTech,
Inc., Waltham, MA, 02452
The stress level in a plant may be directly associated with the intensity
of the Kautsky effect (the sudden increase in fluorescence emission
by chlorophyll following a dark adaptation). The decrease in photosynthetic efficiency, linked with the rate of photochemistry of plants
under stress, provides a definitive signature (graphical pattern) that can
be quantified and monitored, even for plants that have no visible stress
symptoms. Using a prototype GrowScanner®, signature differences
in plants under nitrogen and water stress, as compared with plants
not under stress, could be detected and measured. Returning stressed
plants to a nonstressed condition returned the stress signatures to that
of control plants not under stress. Development of the technology may
provide a relatively quick, presymptomatic methodology for detecting
plant stress without sacrificing plant tissue.
(455) Differential Patterns of Expression and Regulation
of Two Dehydrin Genes from Peach (Prunus persica) Bark
Tissues
Michael Wisniewski*1, Carole Bassett1, Timothy Artlip1,
Jenny Renaut2, Robert Farrell3
1
AFRS, USDA-ARS, Kearneysville, WV, 25430; 2Gabriel Lippmann (Cellule de Recherche
en Environnement et BiotechnologieS - CREBS), Centre de Recherche Public, av. de la
Faiencerie, 162a, Luxembourg, L-1511, Luxembourg; 3Pennsylvania State University,
Biology, York, PA, 17403
We have characterized the seasonal accumulation of transcripts and
proteins in peach (Prunus persica), particularly a 60 kDa dehydrin
(PCA60; PpDhn1). Recently, we have isolated another dehydrin gene
(PpDhn2). The present report compares the structural organization of
the two dehydrin genes, their promoters, and the response of the genes
to temperature, photoperiod, and water deficit. Trees were exposed for
3 or 5 weeks to either short day (SD) or long day (LD) photoperiods at
either 25 or 5 °C. Additional experiments exposed trees to a period of
water deficit followed by recovery. Transcript abundance of both genes,
as assessed by RT-PCR, was determined, in response to the different
photoperiods and temperatures as well as a prolonged SD/5 °C regime,
from monthly-collected field samples, and trees subjected to water deficit.
Results indicated that water deficit increased transcript abundance of
both genes, but their abundance differed dramatically in response to low
temperature and seasonal cues. Surprisingly, neither gene exhibited a
significant elevation in transcript abundance in response to SD conditions. The lack of response of PpDhn1 to SD is problematical given the
observation that transcript levels in field-collected samples begin to increase substantially in September, prior to the onset of cold temperatures.
Analysis of the promoter regions and cis-acting elements suggest that
ABA may play an important role in seasonal expression, interacting with
photoperiod in field conditions. Two CRT/DRE elements are present in
the promoter region of PpDhn1, but absent in the promoter of PpDhn2.
(456) Abiotic Stress Responses in Cucumber (Cucumis
sativus L.) Plants Expressing the Arabidopsis thaliana
Transcriptional Activators-CBF1 and CBF3
Mohamed Tawfik, Alejandra Ferenczi, Daniel Enter,
Rebecca Grumet*
Michigan State University, Horticulture, Plant and Soil Sci. Bldg., East Lansing, MI, 48824
Abiotic stresses (e.g., salinity, drought, cold, oxidative stress) can be
major factors limiting plant productivity worldwide. We sought to
HORTSCIENCE, VOL. 40(4), JULY 2005
6/20/05 5:01:37 PM
Specific activity in two kale cultivars was highly variable, but tended
to have highest activity from pH 5.0–6.0. In both cauliflower cultivars
from Fall 2000, Fall 2001, and Spring 2002, optimal pH was around pH
6.0. In Spring 2000, however, specific activity was highest at pH 5.0.
Maximum specific activity in both cabbage cultivars occurred in the
pH range 5.5–6.0 in Fall 2000, Fall 2001, and Spring 2002. In Spring
2000, specific activity in ‘Red Acre’ cabbage was uniform across the
range pH 4.5–5.5 and maximum specific activity was at pH 5.0 for
‘Early Round Dutch’ cabbage. Both brussels sprouts cultivars had pH
maxima around pH 5.5–6.0 and significantly lower activity at pH 4.5.
Specific activity in broccoli was much like that of cauliflower in that
highest activity occurred around pH 5.5–6.0 in Fall 2000, Fall 2001,
and Spring 2002, but in Spring 2000, maximum activity was at pH 5.0.
These results indicate that in most cases, pH optima were in the range
5.5–6.0, but varied somewhat with season and genotype.
(457) An Approach-grafted, Split-rooted Apple System
to Evaluate the Effects of Partial Rootzone Drying and
Deficit Irrigation on Tree Water Relations
1
Poster Session 26—Fruit Crop Physiology
19 July 2005, 1:15–2:00 p.m.
Poster Hall–Ballroom E/F
(319) Mycorrhizal Symbiosis and Response of Sorghum
Plants to Combined Drought and Salt Stresses
Robert Augé*1, Keunho Cho2, Jean Stutz3, Heather Toler1
Todd C. Einhorn*1, Horst W. Caspari1, Steve Green2, Greg Litus1
1
Colorado State University, Department of Horticulture and Landscape Architecture, Fort
Collins, CO, 80523; 2HortResearch, Environmental and Risk Management, Palmerston
North, New Zealand
One-year-old ‘Gala’/M7 apple trees were potted into 30-L containers
and approach-grafted about 45 cm above the graft union in late Spring
2003. Trees were grown with both tops for the remainder of the 2003
season in a greenhouse. In Apr. 2004, one of the tops was removed.
Trees were fully watered by an overhead irrigation system until July
2004, when trees were subjected to one of four irrigation regimes:
control received >100% of ETc applied evenly to the two pots; PRD100
received >100% ETc applied to one pot only; and two regimes received
50% ETc applied to either one (PRD50) or both pots (DI50). Both
gravimetric (tripod) and volumetric (time-domain reflectometry) soil
moisture measurements were taken daily prior to and after irrigations.
In addition, heavy isotope H2O (18O) was applied to one of the two root
compartments and analyzed in the leaves to further determine the validity of the model. Sap flow was monitored in six split-rooted trees using
miniaturized heat-pulse probes inserted into the stem above the graft
union and into each of the two root systems below the graft union. Under
fully irrigated conditions, root sap flow was proportional to root trunk
cross-sectional area, and was not a function of root system origin (i.e.,
roots of mother plant with original top remaining or roots of daughter
plant with original top detached). Water uptake from a previously dried
root zone was rapid when the irrigated side was switched, but much
more gradual when the other side was maintained wet. Interactions
between soil moisture and sap flow in relation to factors governing
canopy demand will be presented.
(458) pH Optima for Myrosinase Activity in Crude
Extracts from Cruciferous Crops
Craig S. Charron, Carl E. Sams*
The University of Tennessee, Department of Plant Sciences, Knoxville, TN, 37996-4561
There has been significant interest in the glucosinolate-myrosinase
system in plants of the Brassicaceae due to accumulating evidence that
some glucosinolate degradation products are anticarcinogenic and/or
suppressive to plant pathogens. Because glucosinolate hydrolysis is
catalyzed by endogenous myrosinase, characterization of myrosinase
activity is important for elucidating the potential bioactivity of crop
glucosinolates. We measured the specific activity in citrate-phosphate
buffer extracts across the pH range 4.5–6.5 of two cultivars each of
five Brassica groups grown during two fall and two spring seasons.
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final6_20July HS.indb 1037
University of Tennessee, Department of Plant Sciences, Knoxville, TN, 37996-4561;
University of Florida, Plant Medicine Program, Gainesville, FL, 32611-0680; 3Arizona
State University, Department of Plant Biology, Tempe, AZ, 85287-1601
2
Colonization of roots by arbuscular mycorrhizal (AM) fungi can increase
host resistance to drought stress, although the effect is unpredictable.
Since AM symbiosis also frequently increases host resistance to salt
stress, and since drought and salt stress are often linked in drying soils,
we speculated that the AM influence on plant drought response may
be linked to AM influence on salt stress. We tested the hypothesis that
AM-induced effects on drought responses would be more pronounced
when plants of comparable size are exposed to drought in salinized soils.
In two greenhouse experiments, several water relations characteristics
were measured in sorghum plants colonized by Glomus intraradices,
Gigaspora margarita, or a mixture of AM species during a sustained
drought following exposure to salt treatments (NaCl stress, osmotic
stress, or soil leaching). The presence of excess salt in soils widened
the difference in drought responses between AM and non-AM plants
in just two instances: days needed for plants to reach stomatal closure,
and promotion of stomatal conductance. In other instances, the addition
of salt tended to nullify an AM-induced change in drought response;
e.g., an AM effect on the decline in leaf or soil water potential required
to cause stomatal closure disappeared when soils were salinized. Our
findings confirm that AM fungi can alter host response to drought but
do not lend much support to the idea that AM-induced salt resistance
might help explain why AM plants can be more resilient to drought
stress than their non-AM counterparts.
POSTERS–TUESDAY
increase abiotic stress resistance in cucumber by expressing the A.
thaliana transcription factors CBF1 and CBF3, which regulate genes
responsible for enhanced dehydration-stress resistance in Arabidopsis. Our previous studies in the greenhouse and field demonstrated
increased salinity tolerance in CBF-expressing cucumber lines. In
the current studies, we tested response of CBF-cucumber plants to
drought, chilling, and oxidative stresses. Transgenic cucumber plants
subjected to drought stress in the greenhouse showed elevated levels
of the stress-inducible compatible solute, proline, compared to the
nontransgenic controls. Preliminary results also indicate greater photochemical efficiency in CBF-expressing plants under drought stress
conditions compared to the nontransgenic controls. Under nonstressed
conditions, there were no significant differences in growth between
the transgenic and the nontransgenic cucumber plants; however, after
a cycle of drought stress, CBF-cucumber lines had less growth reduction compared to the nontransgenic counterparts. The advantage in
growth was less pronounced after a second cycle of drought. We also
evaluated the transgenic cucumber plants under chilling conditions (i.e.,
low, nonfreezing temperatures within the 0 to 12 °C range). Based on
plant height and cotyledon and leaf damage measurements, transgenic
cucumber seedlings did not show chilling tolerance compared to the
wild-type control. The response of transgenic CBF-cucumber plants to
oxidative stress using methyl viologen is also being evaluated.
(320) Influence of Light Microclimate on the Growth,
Yield, and Fruit Quality of Apple
Zimian Niu*1, Dapeng Zhang2, Jicheng Zhan2, Curt Rom3
1
Horticulture, P.R. China; 2Pomology, Horticulture, P.R. China; 3University of Arkansas,
Horticulture, Fayetteville, AR, 72701
Influence of photosynthetically active radiation (PAR) microclimate in
the canopy of four training systems [open-center with high trunk (OH);
open-center with middle trunk (OM); open-center with low trunk (OL);
and a traditional round canopy (RC)] on the growth, yield and fruit
quality of apple were studied in the Beijing area. The results showed
that: 1) the growth and yield potential were affected by canopy light
microclimate. The average leaf chlorophyll content from OH, OM and
OL systems was 12.3% to 18.1% greater than that from the RC system.
Trees from OH, OM, and OL systems produced 84.2% to 89.7% of
shoot forming flower clusters compared to only 47.3% to 50.9% of the
RC shoots. Training system did not affect total yield of 8-year-old trees,
but in 10-year-old trees the RC system had lower yields compared with
open-center systems. 2) Fruit quality was also affected by canopy light
microclimate. The average anthocyanin content in the skin of fruit from
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6/20/05 5:01:39 PM
OH, OM, and OL systems was 35.9% to 46.1% higher than that from
the RC system, but chlorophyll content from the OL system was higher
than in the open-center systems. Meanwhile, the contents of TSS and
esters in apple flesh from the open-center systems were significantly
higher than that from the RC system. 3) When the relative value of
PAR in canopy exceeded 33.8%, the growth index of trees (chlorophyll
: return-bloom ratio) exceeded 66.6% and the fruit quality index (TSS
× anthocyanin) exceeded 94.7%. When PAR was less than 20.6%, the
growth index was under 37.2% and the fruit quality index was under
67.5%. PAR value was significantly correlated with the growth and fruit
quality index in the four training systems, and the total canopy volume
of higher PAR (exceeding 33.8%, relative value) from OH, OM, and
OL systems was 37.1% to 45.0% greater than that from the RC system.
(321) Rapid and Differential Rates of Root Browning in
Apple Trees under Different Irrigation Treatments
Katie Palanjian*1, Luis Valenzuela1, Denise Neilsen2,
Gerry Neilsen2, David Eissenstat1
1
Pennsylvania State University, Department of Horticulture, University Park,
PA, 16802-4200; 2Agriculture Canada, PARC,Summerland, BC, V0H 1Z0,
Canada
As roots change color from white to brown, their absorptivity for water
and nutrients typically diminishes. The effects of irrigation on root pigmentation were studied during 2003 and 2004 in Summerland, British
Columbia, using an experimental orchard of ‘Golden Delicious’ apple
trees on M9 rootstocks. Root pigmentation was monitored weekly over
the growing season using a minirhizotron camera inserted into clear
plastic tubes in the root zone. Each tree had two emitters, one on either
side of the bole and ≈30 cm from the trunk. Four irrigation treatments
were tested: full irrigation with replenishing 100% of daily evapotranspiration (ET) on both sides of the tree (100% both), 50% ET irrigation
on both sides (50% both), irrigating alternating sides of the tree with
50% ET (50% alternating) and one-sided irrigation at 50% ET (50%
one-side). The 50% alternating irrigation treatment simulated the irrigation practice of partial root zone drying where irrigation was alternated
about weekly from one side of the tree to the other. Root pigmentation
was remarkably fast among these trees, with median days to browning
ranging from 4 to 10 days among treatments. For 50% one-side trees,
root pigmentation on the dry side of the tree was much faster than roots
on the wet side (4 and 7 days, respectively; P < 0.007). Otherwise, no
additional significant effects of irrigation on pigmentation were detected.
(322) The Effect of Plant Growth Regulators and Time of
Plantings on Stem Cuttings of Peach cv. Shan-i-Punjab
Sushobitbir Singh Thind*1, Harmander Pal Singh2, Sukhdev Singh1
1
Khalsa College, Faculty of Agriculture, Amritsar, Punjab, 143001, India; 2University of
Guelph, Department of Plant Agriculture, Guelph, Ontario, N1G 2W1, Canada
Peach [Prunus persica Batsch. (L.)] is a major fruit of northern India,
which is commercially propagated through stem cuttings. There is a
scarcity of information available on the effect of plant growth regulators
(PGRs) and time of plantings on rooting of peach stem cuttings. Studies
were conducted to learn the effects of various PGRs and planting times
on stem cuttings of peach cv. Shan-i-Punjab at the fruit nursery of the
Horticulture Department, Khalsa College, Amritsar, India, in 2001 and
2002. The study on stem cuttings, taken from the middle portion of the
shoot, compared three PGRs: indolebutyric acid (IBA), indoleacetic acid
(IAA), and naphthaleneacetic acid (NAA), each at concentrations of 50,
100, and 200 mg·L-1 and two planting dates (20 Dec. and 20 Jan.). Cuttings
were treated for 24 hours before keeping under moist sand for 1 month for
callusing. Callused cuttings were planted in the field. Measurements on
sprouting percentage, survival percentage, plant height, shoot diameter,
number of leaves per plant, leaf size, average root length, and root weight
per cutting were recorded. The study showed that, overall, auxins had
significant effect on the success and rooting character of peach plants
over the control. The greatest sprouting and survival percentage, plant
height, leaf area, and shoot diameter was exhibited by IBA followed by
IAA and NAA. IBA at 100 ppm proved to be the most suitable PGR for
improving success along with other rooting and vegetative characters
of the plant. The cuttings planted on 20 Dec. gave a higher percentage
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final6_20July HS.indb 1038
of success (55.32%) over those planted on 20 Jan. (33.04 %), during
both years of study. The other plant characteristics, such as average root
length, plant height, leaf area, and plant height, of cuttings planted on
20 Dec. also showed greater success during both years.
(323) Alternate Approaches for Evaluating Horticultural
Efficiency
Timothy L. Righetti1, Carmo Vasconcelos1 David R. Sandrock*2,
Samuel Ortega3, Yerko Moreno3
1
Oregon State University, Horticulture, Department of Horticulture, Corvallis, OR, 97331;
University of Florida, Environmental Horticulture, Gainesville, FL, 32611; 3University of
Talca, Facultad de Ciencias Agrarias, Talca, 747-721, Chile
2
Four ratio-based efficiency expressions (yield/trunk cross-sectional area,
yield/canopy area, yield/pruning weight, CO2 assimilation/leaf area) were
evaluated. These expressions depend on the size of the denominator if
the function describing the relationship between the denominator and
the numerator has a non-zero intercept. When this occurs, it is difficult
to determine if statistically different efficiency expressions reflect
physiological differences or are caused by comparing expressions with
different sized denominators. When denominators and numerators of
efficiency expressions are plotted, the edge of the data cloud can often be
statistically identified. The function describing the edge of the data cloud
defines the maximum possible value (MPV) obtainable for a given value
of the denominator. The percentage of MPV (%MPV) is an alternate efficiency expression that is not influenced by differing trunk cross-sectional
area, canopy area, pruning weight, or leaf area. The difference between
MPV and observed performance can be used to define improvement
potential (IP). These alternate assessments can supplement traditional
efficiency expressions. It is also possible to determine if statistical differences in traditional efficiency expressions are caused by differences
in potential, differences in a plant or leaf’s ability to achieve its potential,
or differences in the size of the efficiency expression denominators.
(324) Irrigation Effects on Fine Root Dynamics in Peach
(Prunus persica)
Christina Wells*, Desmond Layne
Clemson University, Horticulture, Clemson, SC, 29634
We are using a minirhizotron camera system to observe fine root dynamics beneath irrigated and nonirrigated peach trees. Our long term goals
are: 1) to relate the timing of fine root production to tree phenology,
soil water content, and soil temperature; and 2) to determine how fine
root architecture and demography differ between trees with and without
supplemental irrigation. In early 2002, minirhizotrons were constructed
and installed beneath each of 72 open-center, 4-year-old ‘Redglobe’
peach trees at the Musser Fruit Research Farm near Clemson University.
Beginning in May 2002, videotaped images from each minirhizotron
were collected at 2-week intervals; notes on tree phenology were also
recorded biweekly. Videotapes were digitized in the lab, and information on root length, diameter, appearance and longevity was extracted
from the images. Soil temperature and volumetric water content were
measured in the orchard throughout the growing season. In the 2 years
following minirhizotron installation, irrigated trees allocated a significantly greater percentage of their fine root length to the upper soil layers
and exhibited less root branching than nonirrigated trees. Fine roots
produced by irrigated trees lived significantly longer: irrigated trees
had a median root life span of 165 days, while nonirrigated trees had a
median root life span of only 115 days (P < 0.001; proportional hazards
regression). Fine roots from irrigated trees remained in the physiologically active “white” state for an average of 10 days longer than roots
from nonirrigated trees (P < 0.001). Data from 2002–03 indicate that
the trees produce new root flushes at least three times during the year,
with a significant flush occurring immediately after harvest.
(325) Soil Solarization and Methyl Bromide Fumigation
Alter Fine Root Dynamics at a Peach Replant Site
Shann Tanner, Christina Wells*, Gregory Reighard
Clemson University, Horticulture, Clemson, SC, 29634
The effectiveness of soil solarization as an alternative to methyl bromide
HORTSCIENCE, VOL. 40(4), JULY 2005
6/20/05 5:01:40 PM
Poster Session 27—Genetics and Germplasm 2
19 July 2005, 1:15–2:00 PM
Poster Hall–Ballroom E/F
(7) Molecular Phylogenetic Analysis of Genes of the
Carotenoid Pathway in Cucurbita
Marilyn Rivera-Hernández1, Linda Wessel-Beaver*1,
José X. Chaparro2
1
University of Puerto Rico, Mayaguez Campus, Agronomy and Soils, Mayaguez, PR,
00681-9030; 2USDA-ARS-HRL, Ft. Pierce, FL, 34942 (currently at the Univ. of Florida,
Dept. of Horticulture, Gainesville, FL 32611)
(WRPIS) in Pullman, Wash. This collection comprises 269 accessions,
of which 153 are hardneck (flower producing) types. The fertility
characteristics of these accessions was evaluated in the field at Pullman, Wash. After the spathes opened, bulbils were removed from all
the evaluated accessions to facilitate flower development. The umbel
and flower characteristics taken were anther color, flower color, flower
shape, stigma position, flowers per umbel, umbel diameter, umbel shape,
umbel defects, bulbil size, bulbil color, ease of bulbil removal, spathe
opening, pollen production, and pollen viability. Of the 153 accessions,
10 produced only partial scapes with bulbils midstalk and no seed
production capability. Viable pollen was shed in 85 accessions with
viability ranging from 8% to 85%. Open-pollinated seed was generated
by 19 of the Pullman, Wash., grown accessions. Seed production was
low with yields from 6 to 91 seeds per accession.
(9) Compositional Characterization of a Garlic
Germplasm Collection
Marita Cantwell*, Gyunghoon Hong, Ron Voss
University of California, Dept. Plant Sciences, Davis, CA, 95616
A USDA germplasm collection of garlic (Allium sativum) and related
species (A. ophioscorodon, A. longicuspis) has been evaluated for horticultural characteristics and composition under California production
conditions for several years. In 2004, 198 of the 217 accessions in the
collection were evaluated. Bulbs were manually harvested late June to
early July, cured about 3 weeks shaded at ambient temperatures, and
the outer whorl of cloves manually peeled. Bulb and clove weights and
percentage of dry matter were determined. Freeze-dried garlic powder
was analyzed for alliin (precursor of flavor and health compounds)
concentrations by HPLC. Thiosulfinates (mostly allicin, responsible
for flavor and pungency) were determined by a spectrophotometric
assay. Among the accessions evaluated in 2004, the percentage of dry
matter ranged from 32.8% to 44.9%. Alliin content varied from 8.9 to
29.7 mg·g-1, and thiosulfinate concentrations ranged from 32.7 to 114.0
μmol·g-1. For comparison, the widely grown varieties California Early
and California Late averaged 39.5% and 40.8% dry matter, 18.6 and
20.6 mg·g-1 alliin, and 68.1 and 78.8 μm·g-1 thiosulfinates.
Squash and pumpkins (Cucurbita sp.) are important contributors of
beta-carotene to the diet. Consumers of tropical pumpkin and butternut
squash (both C. moschata Duchesne) prefer a deep orange mesocarp
color. Color intensity is related to carotene content. Among the five
domesticated Cucurbita species, C. moschata and C. argyrosperma
Huber have a close relationship. In crosses between these two species,
fertile F1 plants can be easily obtained when using C. argyrosperma
as the female parent. This research studied the relationship between
and within C. moschata and C. argyrosperma by sequencing three
genes in the carotenoid biosynthesis pathway and generating gene
trees. Genotypes used in the study differed in flesh color from very
pale yellow to dark orange. In some cases, haplotypes were associated with a particular mesocarp color. Further study of these types of
associations may improve our understanding of color development
in Cucurbita. The frequency of single nucleotide polymorphisms
(SNPs) in the sequenced fragments was low. There were more SNPs
and more heterozygotes among C. moschata accessions than among
C. argyrosperma accessions. Haplotypes of the outgroups (C. ficifolia
C.D. Bouché and C. maxima Duchesne) were always distinct from C.
moschata and C. argyrosperma. These later species had both distinct
haplotypes and shared haplotypes. Haplotypes shared among species
tended to be maintained in the same branch of the phylogenetic tree,
suggesting either gene flow between the species or a common ancestral gene. Both explanations suggest a close genetic and evolutionary
relationship between C. moschata and C. argyrosperma.
Watermelon [Citrullus lanatus (Thunb.) Matsum. & Nakai] is a diverse
crop, with much variability for fruit and seed traits. This study measured
the inheritance of scarlet red flesh color, egusi seed type, yellow belly
(ground spot) rind pattern, and intermittent stripes on the rind. Scarlet
red is a dark red flesh color found in ‘Dixielee’ and ‘Red-N-Sweet’.
Egusi seed is an unusual mutant having a fleshy pericarp adherent to
the seed coat found in PI 490383 and PI 560006. Yellow belly is found
in ‘Black Diamond, Yellow Belly’. Intermittent stripes are found in
‘Navajo Sweet’, which has narrow dark stripes that are irregular or
nearly absent across the fruit. In order to study the inheritance of these
traits, six generations, including parents, crosses, and backcrosses (Pa,
Pb, F1, F2, BC1Pa, BC1Pb), were produced in each of seven crosses.
Phenotypic data were recorded in the field, and analyzed with the
Chi-square method for the segregation of Mendelian genes. Scarlet red
color in ‘Dixielee’ was allelic to scarlet red color in ‘Red-N-Sweet’.
Four new genes were identified and named, in conformance with gene
nomenclature rules for Cucurbitaceae: Scr for scarlet red, eg for egusi
seed, Yb for yellow belly, and ins for intermittent stripes. Thus, we have
added four new genes to the 52 morphological and disease resistance
genes already published.
(8) Summary of Fertility Characteristics of the USDA
Garlic Collection When Grown in Pullman, Washington
(11) Inheritance of Resistance to Zucchini Yellow Mosaic
Virus-Florida Strain in Watermelon
(10) Four Genes Controlling Watermelon Fruit and Seed
Traits
Gabriele Gusmini, Todd C. Wehner*
North Carolina State University, Horticultural Science, Raleigh, NC, 27695-7609
Barbara C. Hellier*, Marie Pavelka
Nihat Guner1, Todd C. Wehner*2
USDA-ARS, Western Regional Plant Introduction Station, Pullman, WA, 99164-6402
1
The USDA garlic (Allium sativum and Allium longicuspis) collection
is maintained at the ARS, Western Regional Plant Introduction Station
HORTSCIENCE, VOL. 40(4), JULY 2005
final6_20July HS.indb 1039
POSTERS–TUESDAY
(MBr) fumigation in replanted peach orchards was investigated at the
Musser Fruit Research Farm near Clemson, S.C. A split plot experimental design was used, with soil treatment as the whole-plot factor
and rootstock as the sub-plot factor. In Spring 2002, preexisting trees
were removed from the study site, and six orchard rows were cultivated
and subsoiled. In June, two rows were covered with clear polyethylene
sheeting and solarized for the remainder of the summer. In November,
two additional rows were treated with MBr (474.3 kg·ha-1), while the
two remaining control rows received no soil sterilization treatment. In
Jan. 2003, 36 ‘Redglobe’ peach trees budded on Guardian™ or Lovell
rootstock were transplanted to the site, and one minirhizotron was installed beneath each tree. Minirhizotron observations were made every
14–21 days from Feb. through Oct. 2003, and stem caliper measurements
were taken on four dates during this interval. Trees grew significantly
larger in the MBr and solarized rows than in the control rows (P < 0.1;
Tukey’s HSD), but there were no differences in stem caliper growth between MBr and solarization-treated trees. Reduced aboveground growth
in control trees may have been related to greater carbon expenditure
belowground: in the absence of soil sterilization, fine root median life
spans were reduced by 27–28 days (P < 0.0001; proportional hazards
regression) and rates of root production and mortality were significantly higher (P < 0.1; repeated measures ANOVA). Solarization and
MBr fumigation appeared to provide similar benefits in reducing root
turnover and improving aboveground growth at this site.
Sakata Seed, Plant Breeding, Fort Myers, FL, 33970-1118; 2North Carolina State University,
Horticultural Science, Raleigh, NC, 27695-7609
Inheritance of resistance to zucchini yellow mosaic virus-Florida
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6/20/05 5:01:42 PM
strain (ZYMV-FL) was studied in the resistant watermelon accession
of PI 595203 (Citrullus lanatus var. lanatus), an egusi type originally
collected in Nigeria. The F1, F2, and BC1 generations derived from the
cross ‘Calhoun Gray’ × PI 595203 and ‘New Hampshire Midget’ × PI
595203 were used to study the inheritance of resistance to ZYMV-FL.
Seedlings were inoculated with a severe isolate of ZYMV-FL at the first
true leaf stage and rated on a 0 to 9 scale, based on the severity of virus
symptoms. A single recessive gene was found to control resistance, for
which we propose the symbol zym-FL2. The gene probably was not
allelic to the previously published gene, zym-FL, for resistance to the
Florida strain of ZYMV in the accession PI 482261, since PI 482261
was not resistant to the ZYMV-FL isolate used in our tests.
(12) Detection of QTL for Three Individual Sugar
Compositions in Muskmelon
S. Park*1, J. Sinclair1, K. Crosby1, K. Yoo*2, L. Pike2
1
Texas A&M University, Texas Agricultural Research and Extension Center, Weslaco,
TX, 78596; 2Texas A&M University, Vegetable & Fruit Improvement Center, College
Station, TX, 77843
The ratio of individual sugar compositions is an important fruit quality trait in muskmelon. Our objective was to identify RAPD markers
associated with QTL for percentage of each individual sugar (sucrose,
glucose, and fructose) using bulked segregant analysis in an F2 population
derived from the melon cross of ‘TAM Dulce’ (high sucrose percentage
of total sugars) x TGR1551 (low sucrose percentage of total sugars).
Continuous distributions for sucrose, glucose, and fructose percentages of total sugars were observed in the genetic population indicating
quantitative inheritance for the traits. A significant positive correlation
was observed between sucrose percentage and sucrose (r = 0.89) or
soluble solids (r = 0.33), whereas a significant negative correlation was
noted between sucrose percentage and glucose percentage (r = –0.85)
or fructose percentage (r = –0.58). A total of 500 primers was used to
screen between low and high DNA bulks for three individual sugar
percentages. Ten RAPD markers, four amplified from ‘TAM Dulce’
and six amplified from TGR1551, were significantly associated with
QTL for at least one individual sugar percentage. Of the 10 markers
identified, six were consistently associated with two to three traits.
The OAU13.1350 obtained from ‘TAM Dulce’ accounted for 13% and
19% of the phenotypic variation for sucrose and glucose percentages,
while OAW06.600 obtained from TGR1551 explained 17% and 18%
of the variation for the two traits. The OAA09.350 and OAU05.600
markers accounted for 4% to 13% of the variation for three sugar
percentages. These markers associated with QTL for three individual
sugar compositions could be useful in melon breeding for improving
the mature fruit quality.
QTLs in the RILs is underway. Co-localizations of QTLs with several
ESTs and RGAs were observed, suggesting potential involvement of
the latter markers with EB resistance. Furthermore, co-localizations
were observed among QTLs, ESTs, and RGAs and several known
tomato vertical disease resistance genes. Possible occurrence of such
co-localization in the RIL population will be reported. It is speculated
that candidate-gene approach is an effective way of identifying and
mapping new R genes in tomato. This study may lead to the identification of genes underlying EB resistance in tomato.
Poster Session 28—Ornamental/Landscape and Turf 1
19 July 2005, 1:15–2:00 p.m.
Poster Hall–Ballroom E/F
(79) All-America Daylilies: Landscape Performance and
Rust Observations
Allen Owings*1, Gordon Holcomb2, Anthony Witcher1,
Allen Broyles3, Edward Bush1
1
LSU AgCenter, Horticulture, Baton Rouge, LA, 70803; 2LSU AgCenter, Plant Pathology
and Crop Physiology, Baton Rouge, LA, 70803; 3LSU AgCenter, Burden Center, Baton
Rouge, LA, 70809;
All-American daylily cultivars named from 1994–2004 were evaluated
for landscape performance and daylily rust (Puccinia hemerocallidis)
susceptibility during 2003 and 2004. Cultivars included ‘Black-Eyed
Stella’, ‘Bitsy, ‘Leebea Orange Crush’, ‘Plum Perfect’, ‘Judith’, ‘Starstruck’, ‘Frankly Scarlet’, ‘Lullaby Baby’, ‘Lady Lucille’, and ‘Chorus
Line’. Bareroot plants were planted in raised beds composed of an
Olivier silt loam soil in full sun and received irrigation as needed to
prevent stress. Visual quality ratings were made weekly from 19 Apr.–25
Oct. 2003 and 15 Mar.–20 Sept. 2004. Visual quality ratings included
growth habit, based on compactness, foliage color, uniformity, and
overall aesthetics, and flowering, based on longevity and visual appeal.
Other flower observations were made in regard to time in bud and peak
blooming periods over the same time frames. Flowering observations
indicated that ‘Black Eyed Stella’ and ‘Bitsy’ were the only cultivars
showing reliable repeat bloom potential. Among the other cultivars,
‘Judith’ was the earliest to bud and bloom, but also had a blooming
period of only 2–3 weeks compared to 4–5 weeks of bloom for other
cultivars. Daylily rust ratings were taken in Sept. and Nov. 2003 and
in Aug. and Nov. 2004. Rust was most severe on ‘Judith’, ‘Leebea
Orange Crush’, ‘Starstruck’, and ‘Lady Lucille’. ‘Judith’ and ‘Leebea
Orange Crush’ showed rust symptoms earlier than other cultivars. ‘Plum
Perfect’, ‘Frankly Scarlet’, ‘Bitsy’, ‘Black Eyed Stella’, and ‘Lullaby
Baby’ were least susceptible to daylily rust.
(13) Comparative Mapping of Early Blight Resistance
QTLs and Candidate Resistance Genes in F2, F3, F4 and a
RIL Population of Tomato
(80) Calculating Base Temperature and Leaf Appearance
Rate for Sweet Viburnum
Hamid Ashrafi*, Arun Sharma, David Niño-Liu, Liping Zhang,
Majid Foolad
1
The Pennsylvania State University, Dept. of Horticulture, University Park, PA, 16802
In crop models, it is important to determine the leaf area, because the
amount of light interception by leaves influences two very important
processes in the plant: photosynthesis and evaporation. Leaf area is
dependent on leaf appearance and expansion rates. Leaf appearance
rate is driven mainly by temperature. Although the influence of temperature on leaf area development is well known for several agronomic
crops, there is no information for woody ornamentals. An experiment
was conducted to study the relationship between temperature and leaf
appearance of container-grown sweet viburnum. Plants were grown in
field conditions in Gainesville, Fla., during two growing periods (Apr.
to Aug. 2004 and Aug. 2004 to Jan. 2005). Daily maximum and minimum temperature and leaf appearance were recorded. Linear regression
equations were fitted to data and maximum and minimum temperature
and leaf appearance were recorded. Linear regression equations were
fitted to data and base temperature was assumed to be 8 °C. Thermal
time (°C d) was calculated as daily average maximum and minimum air
temperature minus the base temperature and was regressed against leaf
number. The sum of accumulated thermal time was found to be linearly
Most cultivars of tomato (Lycopersicon esculentum) are susceptible to
early blight (EB), a devastating fungal (Alternaria solani) disease of
tomato in the northeast and eastern part of the U.S. The most economic
and durable measure of disease control is by using genetic resistance.
There is limited EB resistance within the cultivated tomato. However,
genetic sources of resistance exist within the tomato-related wild species
L. hirsutum and L. pimpinellifolium. Early blight resistance does not
follow the gene-for-gene model of host–pathogen interaction. Mapping QTLs conferring horizontal resistance is an effective approach
for studying complex resistance traits such as EB. We have developed
F2, F3, F4, and an F2:7 derived RIL population of a L. esculentum × L.
pimpinellifolium cross and evaluated them for EB resistance under field
conditions. Genetic maps were constructed based on the F2 (including 256
RFLP, EST and RGA markers) as well as the RIL population (including
over 220 RFLP and EST markers). In each of the F2, F3, and F4 population, an average of seven QTLs were identified for resistance, which
were highly consistent across populations. Mapping of EB resistance
1040
final6_20July HS.indb 1040
Gisele Schoene1, Thomas Yeager*1, Joe Ritchie1
University of Florida, Environmental Horticulture, Gainesville, FL 32611; 2University of
Florida, Dept. of Agricultural and Biological Engineering, Gainesville, FL 32611
HORTSCIENCE, VOL. 40(4), JULY 2005
6/20/05 5:01:43 PM
correlated with leaf number. Phyllochron, which is the thermal time
between the appearances of successive leaves, was estimated 51 °C per
day. The information presented in this study will be useful in modeling
water use of sweet viburnum in response to environmental conditions.
(81) Fine Fescues and Shade Tolerance
Tara E. Paranick*, N. Suzanne Lang
1
Michigan State University, Horticulture, East Lansing, MI, 48824
(82) Turf Species Affect Establishment and Growth of
Cercis canadensis and Carya illinoiensis
Jason J. Griffin*1, William R. Reid2, Dale Bremer3
1
Kansas State University, Dept. Horticulture, Forestry and Recreation Resources, John
C. Pair Horticultural Center, Haysville, KS, 67060; 2Kansas State University, Dept.
Horticulture, Forestry and Recreation Resources, Pecan Experiment Field, Chetopa, KS,
67336; 3Kansas State University, Dept. of Horticulture, Forestry and Recreation Resources,
Manhattan, KS, 66506
Successful establishment and growth of newly planted trees in the
landscape is dependent on many factors. Weed pressure and water
conservation are typically achieved with either organic mulches or
chemical herbicides applied over the root ball of the newly planted
tree. In the landscape, eliminating turfgrass from the root zone of trees
may be more complicated than resource competition. Studies have
shown that tall fescue (Festuca arundinaceae Schreb.) has allelopathic
properties on pecan trees [Carya illinoiensis (Wangenh.) K. Koch].
Well-manicured tall fescue turf in the landscape may have negative
effects on the establishment and growth of landscape trees as well. A
study was designed to examine the effects of popular turfgrasses on
the growth of newly planted pecan and redbud (Cercis canadensis L.).
Results demonstrate that the presence of turfgrass over the root zone of
trees negatively impacts tree growth. Through two growing seasons,
every growth parameter measured on redbuds (caliper, height, shoot
growth, shoot dry weight, root dry weight, leaf area, and leaf weight)
was significantly reduced by the presence of turf. However, the warm
season bermudagrass [Cynodon dactylon (L.) Pers.] was less inhibitied
than the cool season grasses. The affects of turfgrass on pecan growth
was less significant; however, caliper, leaf area, and root dry weight
were significantly reduced when grown with turf.
(83) New Weed Problems in Midwest Turfgrass and
Horticultural Crops
Pamela B. Trewatha*
Southwest Missouri State University, Agriculture, Springfield, MO, 65804
Through contacts, observations, and travel throughout the midwestern
HORTSCIENCE, VOL. 40(4), JULY 2005
final6_20July HS.indb 1041
(84) Application of AFLP Markers on Taxon
Discrimination of Cultivated Stewartia
Ajay Nair*1, Donglin Zhang1, Dogyan Hu2
POSTERS–TUESDAY
Shaded environments present major obstacles for establishing high
quality, persistent, and resistant turfs. Exogenous fructose applications
are being examined as a potential method to counteract the effects of
shade on turf. This work examines the effectiveness of fructose applications under different light levels on two fine leaf fescue cultivars:
chewings fescue (Festuca rubra var. commutata) ‘SR5100’ and creeping red fescue (Festuca rubra var. rubra) ‘Dawson’. The experiment
was conducted at Michigan State University, East Lansing, inside a
simulated dome environment. The experiment was a randomized complete-block design that began 21 Oct. 2004 with two main factors: light
and fructose. There were three light treatments: ambient light (shaded);
supplemental high light; and supplemental low light. Fructose (0%
or 1.25% weight/volume), dissolved in water with an organosilicone
adjuvant, was applied once per week. Quality and color ratings, clippings, core samples, density, and leaf reflectance were recorded. In
addition, light response curves (LRC) were taken inside an Econoair®
growth chamber using a LI-COR-6400® on the fine fescues, kentucky
bluegrass (Poa pratensis) ‘Cynthia’, and bermudagrass (Cyondon
dactylon) ‘Princess’. Preliminary results show that fructose had no
significant effect in each light treatment for turf quality and color.
However, fructose had a significant impact on clipping weights and
density. The LRC specified the required and potential carbon needs
as well as indicated the threshold levels, respectively, by species. The
impact of fructose alone and in combination with supplemental light
on photosynthesis efficiency will be presented.
United States during Spring and Summer 2004, a number of weed species were noted to be relatively new problems, or growing problems
in turfgrass and/or horticultural cropping situations. These include
hophornbeam copperleaf (Acalypha ostryifolia), garlic mustard (Alliaria
petiolata), blackgrass (Alopecurus myosuroides), Palmer amaranth
(Amaranthus palmeri), waterhemp species (Amaranthus spp.), biennial wormwood (Artemisia biennis), lambsquarters complex species
(Chenopodium spp.), windmillgrass (Chloris verticillata), showy chloris
(Chloris virgata), Asiatic dayflower (Commelina communis), horseweed
(Conyza canadensis), redstem filaree (Erodium cicutarium), toothed
spurge (Euphorbia dentata), dovefoot geranium (Geranium molle),
pitted morningglory (Ipomoea lacunosa), purple deadnettle (Lamium
purpureum), birdsfoot trefoil (Lotus corniculatus), roundleaf mallow
(Malva rotundifolia), star-of-bethlehem (Ornithogalum umbellatum),
cressleaf groundsel (Packera glabella), striate knotweed (Polygonum
erecta), creeping yellow fieldcress (Rorippa sylvestris), lanceleaf
sage (Salvia reflexa), sibara (Sibara virginica), white campion (Silene
latifolia ssp. alba), hairy nightshade (Solanum physalifoium), spiny
sowthistle (Sonchus asper), and others. Possibilities for this increase
or spread include natural invasiveness of the weeds, control of previous weed competitors, resistance to widely used herbicides, changes
in cropping practices, and other weed adaptations to current weed
management methods.
1
University of Maine, Plant Soil and Environmental Sciences, Orono, ME, 04469; 2Beijing
Botanical Garden, Beijing, 100093, China
The natural distribution and cultivated areas of Stewartia taxa are USDA
cold hardiness zones 6 or warmer. One cold-tolerant clone, named
Stewartia ‘UMaine’ (UMaine Silk Camellia), has been growing well at
the University of Maine Littlefield Ornamentals Trial Garden (USDA
Zone 4). The plant also has brilliant red fall color and biennial flowering. Since cold hardiness field evaluation could not provide genetic
information and no other taxa could grow in Zone 4, AFLP markers
were employed to figure out its genetic relativeness with other 16 named
Stewartia taxa. The three primer-pairs generated 360 useful markers
with an average of 120 markers for each taxon. The genetic distance
between S. sinensis and S. rostrata is only 0.031, which indicates that
these two species are very similar and should not be treated as two species or cultivars, at least the plants in cultivation. The largest distance
(0.533) occurs between S. pesudocamellia and S. malacodendron, two
distinguished species accepted by all taxonomists. UMaine Silk Camellia
is a distinguished taxon from all other 16 taxa and S. malacodendron
‘Delmarva’ has the largest genetic distance of 0.453 to it. Although
S. ×henryae ‘Skyrocket’ has the smallest genetic distance of 0.183 to
Stewartia ‘UMaine’, UPGMA phenograms showed that they are not
in a clad at all. AFLP data support that Stewartia ‘UMaine’ is a new
cultivar, which originated from a gene pool of S. pseudocamellia, S.
sinensis, and S. koreana. These molecular results will also be used as
guidance for future Stewartia breeding.
(85) Establishment of Seeded Bermudagrass following
Preplant Application of Transition Herbicides
Shawn Brewer, Michael Maurer*
Texas Tech University, Plant and Soil Science Department, Lubbock, TX, 79409
Transition of perennial ryegrass from bermudagrass athletic fields
in the spring delays the establishment of bermudagrass when the establishment period is limited. The objective of this field study was to
determine the effects of transition herbicides on the establishment of
seeded bermudagrass. Treatments consisted of an untreated control,
foramsulfuron, rimsulfuron, trifloxysulfuron sodium, metsulfuron
methyl methyl, isoxaban, and oxadiazon at low- and high-labeled rates
for transitioning perennial ryegrass. ‘Riviera’ bermudagrass [Cynodon
dactylon(L.) Pers.] seed was seeded immediately after treatment and
2 weeks after treatment. Turfgrass coverage was evaluated visually
and by digital analysis. Although differences between methods of
turfgrass coverage evaluation varied, the differences between treat-
1041
6/20/05 5:01:45 PM
ments were similar. There was no significant differences in turfgrass
establishment between foramsulfuron, rimsulfuron, trifloxysulfuron
sodium, metsulfuron methyl methyl, and the control for either seeding
date or rate. Turfgrass coverage was significantly less for isoxaban
and no turfgrass was established in the oxadiazon treatments. Initial
results of this research indicate that bermudagrass seed can be seeded
immediately following the application of foramsulfuron, rimsulfuron,
trifloxysulfuron sodium, and metsulfuron methyl methyl.
(86) Seed Germination and Seedling Survival of Alnus
maritima (Seaside Alder) in Three Soils in Northern Utah
Heidi1A. Kratsch*
Utah State University, Plants, Soils, and Biometeorology, Logan, UT, 84322-4820
Alnus maritima may have potential for use in home and commercial
landscapes in northern Utah. This fast-growing, fall-blooming shrub
is cold-hardy to USDA hardiness zone 3b and tolerant of nutrient-poor
soils and full sun. Because this taxon is native to low-elevation wetlands,
I seek to determine its response to the high desert soils and climate
of northern Utah. My specific objective was to test germination and
survival of plants from seed sowed in three diverse soil types typical
of the Wasatch front in north-central Utah. Seeds were rinsed with
distilled water and cold-stratified in darkness for 16 weeks between wet
filter paper in sealed petri dishes. Stratified seeds were sowed in flats
filled with soil from each of three sites at the Utah Botanical Center in
Kaysville and held in a greenhouse. Seeds planted in flats filled with
soilless germination mix served as controls. Flats with 60 seeds were
experimental units, and each medium was replicated three times. Soils
ranged from silty loam to loam, nitrate-N was 3.2 to 5.4 mg·kg-1, and
there was 1.4% to 2.9% organic matter. Germination rates were highest
in the soilless mix (50%). Of the three soil types, the highest germination rates (24%) occurred in a loamy soil high in organic matter (2.9%).
Rates were similar (12.5% and 13%) in the other two soils. Seeds of A.
maritima can germinate in soils typical of urban landscapes in northern
Utah, so both the potential for invasiveness and the performance of
plants in the landscape of northern Utah are being evaluated.
(87) Short-term Freeze Stress Attenuation in St. Augustine
Turfgrass with Selected Biostimulants
J. Pablo Morales-Payan*, William M. Stall
University of Florida, Horticultural Sciences Department, Gainesville, FL, 32611-0690
Experiments were conducted to determine the effects of selected biostimulants on St. Augustine turfgrass exposed to short-term periods
of freezing temperatures, which are common in north-central Florida
during March and April. Aqueous solutions of a triterpenic acid-rich
extract from Siberian fir (Abies sibirica) [(TTA), 0 and 300 mg·L-1
a.i.], a seaweed (Ascophyllum nodosum) extract [(CSE), 30 mg·L-1
a.i.], acetylthioproline [(AP), 250 mg·L-1 a.i.], and amino levulinic acid
[(5-ALA), 15 mg·L-1 a.i.] were sprayed on residential St. Augustine
turfgrass about 50 hours prior to the forecasted freezing event. After
freezing, the aesthetic quality of AP-treated St. Augustine turfgrass
was the same as in untreated turfgrass plots, but it was drastically
reduced in turfgrass treated with 5-ALA. In contrast, St. Augustine
tufgrass aesthetic quality was higher in CSE- and TTA-treated plots
than in untreated plots. These results indicate that CSE and TTA may
help alleviate the negative effects of short-term exposure to freezing
temperatures in St. Augustine turfgrass.
(88) The Expressway Partnership: Greening Chicago’s
Highways
A.M. Shirazi*1, C.P. Dunn2
1
The Morton Arboretum, Urban Horticulture Research Lab., Lisle, IL, 60532; 2Chicago
Botanic Garden, Research, Glencoe, IL, 60022
The Expressway Partnership (a project of the Chicagoland Chamber of
Commerce’s Gateway Green Committee) is an urban landscape project
that promises to change the face of the city’s expressways. The Morton
Arboretum’s Urban Horticulture Research Lab., with the support of
ComEd (Excelon Corp.), since 2001 has been selecting, planting, and
evaluating various cultivars of trees, shrubs, and ground covers in a
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search for the most suitable and sustainable plantings for the expressway
environment. About 470 trees and shrubs were planted plus more than
10,000 groundcovers. In May 2002 these plants were visually evaluated and ranked from 1–5 with one being in excellent condition and 5
being dead. The control plants planted at Urban Horticulture Research
Nursery at the Morton Arboretum had 100% survival. The survival
rates for groundcovers were: Euonymus fortunei (Virginia Creeper)
and Hemerocallis ×daylily (day lily) had 80% to 90% survival rates,
respectively. Pachysandra terminalis (Japanese spurge) plants died
due to either de-icing salt sensitivity, or poor weed control. Syringa
pekinensis (Peking lilac), as well as four Syringa cultivars, ‘President
Grevy’, ‘Summer Charm’, ‘Charles Joly’, and ‘James Mcfarlane’,
had a 100% survival rate. Survival rates for other plants were: Malus
sargentii (Sargent crabapple) 93%; Robina pseudoacacia (black locust)
~93%; Malus cultivars ~75%; and Pinus banksiana (jack pine) 75%.
Cornus sericea (red-osier dogwood) covered with 3 inches of mulch
had a significantly better survival rate (90% to 100%) than the mulch
treatment (60% to 80%). The growth and performance of other trees
and shrubs will be also reported. This research will ensure sustainable
and esthetic urban expressway plantings, while enhancing Chicago’s
stature as a significant urban landmark.
(89) A New Granular Herbicide for Container, Landscape,
and Field-grown Ornamentals
Randy Smith*, Darin Lickfeldt, Dan Loughner, Mike Melichar,
James Breuninger
Dow AgroSciences, Specialty Products, Clovis, CA, 93619
In 2003 and 2004, a new herbicide containing three active ingredients
was evaluated for efficacy on important weed species and the tolerance
of popular ornamental plant species. Currently available ornamental
herbicides differ greatly in the weeds they control and tolerance of
ornamental plants grown in production nurseries. This new granular
product, trade name Showcase, also known by its experimental number,
GF-1162, contains 2% trifluralin, 0.25% isoxaben, and 0.25% oxyfluorfen. With preemergent applications applied to pots artificially infested
with weed seed, GF-1162 demonstrated exceptional control of many
difficult to control species, such as spurge, groundsel, bittercress, oxalis,
and crabgrass. When applied preemergence at 150 lb/acre, GF-1162 was
as efficacious as current standards. At 200 lb/acre, weed control was
exceptional, exceeding all products included in the trials. Ornamental
tolerance to GF-1162 was comparable to that of Snapshot TG, with the
exception of whorled plants. On whorled plants, such as daylily and
hosta, where granular products can be retained on leaf surfaces, products containing oxyfluorfen must be applied with special precautions
to immediately shake or wash granules from leaf surfaces. Even when
whorled plants were injured by GF-1162, they did eventually recover.
GF-1162 received a federal registration in 2004 and state registrations
may be complete as early as Spring 2005, at which time this new herbicide would be made available to ornamental nurseries and lawn care
companies as an alternative to current herbicide options.
(90) Coleus: Landscape Performance Results from 2003
and 2004
Allen Owings*1, Anthony Witcher1, Allen Broyles2
1
LSU AgCenter, Horticulture, Baton Rouge, LA, 70803; 2LSU AgCenter, Burden Center,
Baton Rouge, LA, 70809
Coleus were trialed for landscape performance during 2003 and 2004
at Burden Center in Baton Rouge, La. This included a mid-spring
through fall evaluation in 2003 and a spring through summer and
summer through fall evaluation in 2004. Over 45 cultivars, including the Solar, Hurricane, Stained Glassworks, and Aurora series,
were evaluated. Visual quality ratings were taken twice monthly and
included compactness, foliage color, uniformity, and overall aesthetics. Flower observations were noted. Beds were located in full sun
and consisted of a raised row of an Olivier silt loam soil. Plants were
drip irrigated as needed to prevent stress. A separate study compared
sun and shade (60%) performance of Kong coleus cultivars in the late
summer through fall 2004. The Solar series performed well in 2003
and 2004, and generally had visual quality ratings significantly greater
HORTSCIENCE, VOL. 40(4), JULY 2005
6/20/05 5:01:46 PM
than cultivars in the Hurricane, Stained Glassworks and Aurora series.
Height was also greater in the Solar series. The Hurricane series had
significant flowering early in the evaluation periods, although ‘Louise’
was slower to flower than ‘Benji’ or ‘Jenni’. Kong coleus cultivars in
60% shade were about 50% shorter than those in full sun. ‘Aurora
Black Cherry’ was superior to the other cultivars in the series in terms
of visual quality and slowness to flower. ‘Mississippi Summer Sun’
(a/k/a Razzle Dazzle) and ‘Red Ruffle’ were top performers among the
nonseries cultivars evaluated.
of the students had a paper published in a conference proceedings or
presented a scientific paper outside Hawaii, with only 18% having
presented a paper in Hawaii. Writing assignments, in-class activities,
and evaluations of the writings of others helped students gain intensive
hands-on experience in scientific writing. As a course requirement,
students submitted an abstract and presented a paper at our college’s
annual scientific symposium. Course evaluations indicated this course
was important and valuable in helping enhance the students’ learning
experience.
(91) Gardening in a Bag: A Viable Alternative for
Growing Bedding Plants in the Landscape
(140) Survey of Student Perceptions for Course Delivery
Methods
Clydette M. Alsup*, Pamela A. Trewatha
Kimberly K. Moore*, George E. Fitzpatrick, Jane E. Slane
Southwest Missouri State University, Agriculture, Karls Hall, Springfield, MO, 65804
University of Florida, Environmental Horticulture, Davie, FL, 33314
The rocky Ozarks soils make it difficult for some homeowners to establish ornamental gardens. An alternative to digging in rocky soils is
planting into bags of potting soil. This study evaluated “Gardening in
a Bag” for herbaceous bedding plants. The growth and appearance of
Alternanthera, Capisum annuum, Dianthus, Gazania, Tagetes ‘Wave’,
and upright petunias, Salvia splendens, Spilanthes, Verbena, and Catharanthus roseus were evaluated in 2002 under two planting methods: in
the ground vs. in bags of potting soil. Wave petunias, Dianthus, C.
roseus, and Portulaca grandiflora were evaluated in 2003. All plants
were mulched with 3 inches of coarse sawdust. In 2002, planting method
had no effect on average height for 16 of the 25 cultivars tested. Seven
cultivars were taller when grown in the ground while two cultivars were
shorter in that treatment. Planting method had no effect on average plant
width of 13 of the cultivars. Plant width was greater for nine cultivars
grown in bags, while three cultivars were wider when grown in the
ground. Visual ratings were similar for 14 of the cultivars, regardless
of planting method. In 2003, performance of five species was evaluated
on 3 and 29 July and 5 Sept. Plant height and width were greater on
plants grown in the ground than plants grown in bags on 3 July and
5 Sept. Only plant width was significantly greater in the soil-grown
plants on 29 July, although the greater height trend was still evident.
Plants in the ground had more flowers than plants in bags on 3 July,
but there were no differences in flower number the other two dates.
Visual quality ratings were taken on the second and third dates, with
no differences between treatments. Root soil temperature was higher
in bags than in the ground on all three dates in 2003.
The University of Florida College of Agriculture and Life Sciences
offers the Bachelor of Science degree program in Environmental
Horticulture at the Fort Lauderdale Research and Education Center
(FLREC). Instructors at the FLREC deliver course work and course
work is also presented using a variety of distance education (DE)
technologies. These DE technologies include interactive video conferencing, videotape, and web-based courses. The question often arises
as to how many courses should be delivered using DE versus live onsite instruction. This survey was conducted to ascertain how students
perceive the quality of education they are receiving using a mixture
of delivery methods.
Constituencies
20 July 2005, 12:00–12:45 p.m. Poster Hall–Ballroom E/F
(139) Enhancing Professional Development of Graduate
Students through a Scientific Writing Course
Kent D. Kobayashi*
University of Hawaii at Manoa, Tropical Plant & Soil Sciences, Honolulu, HI, 96822
How do we enhance the learning experience of graduate students in
scientific writing, an essential skill in their professional development?
A graduate course TPSS 711 “Scientific Writing for Graduate Students”
was developed to address this need. Its objectives were to help students
write, analyze, and revise parts of a scientific paper; critically evaluate their own writing and the writings of others; and become familiar
with types of publications. The diverse topics included purpose of
scientific writing; organizing your writing; parts of a scientific paper;
data analysis and growth analysis; writing the content of a poster or
oral presentation; newspaper articles and popular works; extension
publications; technical writing for the general public; thesis/dissertation
writing; a journal editor’s perspective; and reviewing a manuscript.
TPSS 711 had an enrollment of 11 TPSS master’s students. Students
were in their second through fifth semesters of their graduate program.
A student survey showed no student had submitted a manuscript to a
peer-reviewed journal, had a peer-reviewed article published, or had
a newspaper, trade magazine, or popular work published. Only 9%
HORTSCIENCE, VOL. 40(4), JULY 2005
final6_20July HS.indb 1043
Cynthia B. McKenney*1, Ellen B. Peffley2
1
Texas A&M University, Horticulture Sciences, Research and Extension Center, Dallas, TX,
76424; 2Texas Tech University, Plant and Soil Science, Lubbock, TX, 79409-2122
Teaching at a distance has many rewards and challenges inherent in its
delivery. Interactive video conferencing has the advantages of having
audio and visual contact with students during a set class period while
having the disadvantages of scheduling multiple locations and keeping
the equipment functioning at peak performance. Likewise, using a web
platform such as WebCT provides a framework with excellent options
to develop a course that is both audio and visually rich. This solution
also presents its own difficulties as required textbooks change and the
platform version may be upgraded. In this presentation, the advantages
and disadvantages of both formats will be reviewed. In addition, helpful hints for blending these two teaching methods together to create a
custom course will be discussed.
POSTERS–WEDNESDAY
Poster Session 29—Teaching Horticulture to Diverse
(141) Blending Interactive Video Conferencing Classes
with WebCT
(142) Evaluating Student Attitudes toward an
Interdisciplinary Professional Master Degree Specializing
in Landscape Water Conservation as Compared to a
Conventional MS Degree
Cathy Myers-Roche*, Roger Kjelgren
Utah State University, Plants, Soils, and Biometeorology, Logan, UT, 84322
Interdisciplinary graduate degrees are becoming increasingly popular,
filling both employer needs as well as student goals. The Plants and
Soils Department at Utah State University offers an interdisciplinary
master of professional studies in horticulture (MPSH) degree program
specializing in urban landscape water conservation. The MPSH is a
one calendar year degree consisting of a small group cohort with a
strong emphasis on communication and policy development geared
toward creating and managing water conservation programs. Core to
this model is what personality type is drawn to an MPSH degree compared to the traditional, research-based master of science degree. We
are comparing the personality types of 16 students in the MPSH to 15
students in, or having completed, the traditional MS degree program
by using the Myers-Briggs test (MBTI), Strong Interest Inventory (SII)
test, and key informant surveys. Basic MBTI personality categories
in extroversion/introversion, sensing/intuition, thinking/feeling and
judging/perceiving are being evaluated by comparison in contrast as
well as consistency across the two degree types. Key informant surveys
quizzed individual preference regarding the two degrees. Preliminary
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6/20/05 5:01:48 PM
inspection of survey, MBTI and SII results indicate a definite link between type of graduate program and basic personality trait. Students in
or having completed the traditional MS degree program that indicated
a preference for the MPSH degree shared the same personality types
as those in the MSPH program. These preliminary results suggest that
an interdisciplinary professional degree in horticulture focused on a
particular topic can appeal to horticultural undergraduates that might
not otherwise consider a graduate degree.
(143) Development of an Online Certificate Program in
Landscape Horticulture
Karen Stoelzle Midden*, Paul Henry, Amy Boren
Southern Illinois University-Carbondale, Plant, Soil, and Agricultural Systems, Carbondale, IL, 62901
Online courses are easily accessible and have the potential to attract
and recruit a diversity of students. The instructors [also the principal
investigators (PIs)] of an online certificate program in landscape
horticulture have completed the first of a 3-year project in an effort
to provide landscape horticulture courses, including an option for a
certificate, to traditional and nontraditional students. The certification,
consisting of 20 credit hours, will be the first of its type in Illinois
offered by an institution of higher education. The program is aimed
toward traditional college students who may need additional college
credit, and nontraditional students who are pursuing certification out
of interest in career goals or needing continuing education. The Chicago Botanic Garden, a cooperator in this project, has been a driving
force for creation of this program and feels that there is a substantial
demand among its clientele. It is being funded by the SIUC Office of
the Provost and Vice Chancellor Distance Learning Grant. Year one
of this project focused on review and revision of curriculum material
of six existing courses taught by the PIs. The PIs are working closely
with the university’s instructional support for the courses to be delivered by WebCT. To date, the “Appreciation of Landscape Design”
course has received the most emphasis in the conversion. This poster
session will summarize the project to date and projected benefits of
this online program.
FL, 32611-0145;4Univeristy of Arizona, Agricultural and Biosystems Engineering, Tucson,
AZ, 85719; 5University of Arizona, Plant Sciences, Tucson, AZ, 85721-0036;6University
of Florida, Agricultural Education & Communication, Gainesville, FL, 32611-0540; 7The
Ohio State University, Horticulture and Crop Science, Columbus, OH, 43210; 8University
of Vermont, Electrical and Computer Engineering, Burlington, VT, 05405; 9University of
Vermont, Plant and Soil Science, Burlington, VT, 05405-0082
Using a multidisciplinary approach, we are creating an instrument for
utilization in a variety of greenhouse related courses. We now have over
3 hours of edited and titled video segments that were obtained at different locations by the same videographer. The greenhouse businesses in
Arizona, Vermont, Ohio, and Florida were chosen due to their unique
business strategies, level of computerization, type of greenhouse construction, management philosophies, and climate challenges. Individual video
segments are based on nine topics that were covered at each location
including computers, structure, plant life cycle, and labor. The videos
have been placed on a streaming media server and will be burned to a
DVD. An interactive Flash-based greenhouse environment simulator is
nearly complete. This instrument allows students to model greenhouse
environments based on climate data from each of the four video locations. Additionally, a searchable digital repository has been established
that will allow other participants to submit materials for educational use.
This open source software (DSpace) has an integrated distribution license
which streamlines compliance with the Digital Millennium Copyright
Act. Several hundred high quality images have already been uploaded,
described and tagged. Learning assessment tools based on numerical
self-evaluation and verification narratives are also being developed in
conjunction with the multimedia tools. We have created a database of
all the greenhouse courses at 1862, 1890, and 1994 institutions and
hope to build a community of teachers that will utilize and contribute
to the multimedia greenhouse collection. This community has already
grown to include two international greenhouse experts who contributed
interactive software for educational use.
(146) Plantation, Beverage, and Tropical Nut Crops:
Enhancing the Instructional Portfolio of the Horticulture
Curriculum
D.H. Picha*
1
(144) ePortfolios: A Philosophy for Improving Education
in Horticulture
Michael E. Reinert*, Dan T. Stearns
Pennsylvania State University, Horticulture, University Park, PA, 16802
ePortfolios are gaining popularity in academic communities worldwide.
Purposes of ePortfolios include: converting student work from paper to
digital format, thereby allowing it to be centrally organized, searchable,
and transportable throughout their academic lives and careers; promoting
student centered learning and reflection; improving advising; and career
planning and resume building. Pennsylvania State University is investing in the use of ePortfolios in course work throughout the university
system. To facilitate these efforts, the university provides all students
and faculty with 500 MB of hosted web space to create and share their
portfolios. One of the courses using ePortfolios is Horticulture 120,
Computer Applications for Landscape Contracting, in the Landscape
Contracting program. Outcomes of implementing ePortfolios include
increased availability of student work to potential employers, enhanced
recruiting through displays of student work, and enabled reflection on
completed work. Students showed improved quality in project work
because their projects would be publicly available through the Internet
to potential employers, faculty, family, and other students.
(145) Integrating Video, Interactive Animations, Images,
and Assessment toward an Expandable Instructor
Resource for Greenhouse Education
Milton E. Tignor*1, Sandra B. Wilson2, Lisa S. Hightower3,
Efren Fitz-Rodriguez4, Gene A. Giacomelli4, Chieri Kubota5,
Emily Rhoades6, Tracy A. Irani6, Margaret J. McMahon7,
Andrew N. Laing8, David A. Heleba9, Sarah M. Greenleaf9
1
University of Vermont, Plant and Soil Science, Burlington, VT, 05405-0082; 2University
of Florida, Environmental Horticulture, Indian River Research and Education Center Fort
Pierce, FL, 34945-3138; 3University of Florida, IFAS Communication Services, Gainesville,
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final6_20July HS.indb 1044
Louisiana State University, Horticulture, Baton Rouge, LA, 70803
A course entitled “Plantation, Beverage, and Tropical Nut Crops” was
developed in order to expand the content and diversity of the horticulture curriculum at Louisiana State University. The course was designed
for both upper division undergraduates and graduate students in the
plant sciences. The course was intended to broaden the exposure of
both domestic and international students to the world’s most important
plantation, beverage, and tropical nut crops. These crops are generally
not commercially grown in the United States, but include some of the
world’s most economically significant commodities. The selected crops
are typically not covered in existing horticulture or agronomy classes.
Details of the individual crop cultural practices, harvesting methods,
postharvest care, agro-processing, and international marketing are
provided. The instructional materials were formatted for delivery via
compressed video and transmitted to off-campus sites to afford the opportunity of long-distance learning to nontraditional students. The course
was successful in attracting nonhorticulture students and facilitated
interdisciplinary interaction among students from diverse curricula.
(147) In the English Landscape
Michael N. Dana*, Paul C. Siciliano, John L. Larson
Purdue University, Horticulture & Landscape Architecture, West Lafayette, IN, 47907
International travel and study courses for undergraduate students can
be significant academic learning experiences if there is a well-defined
curriculum and high expectations for student performance on homework exercises, class discussions and evaluation instruments. An
interdisciplinary perspective serves to broaden students’ understanding.
“In the English Landscape” is a three-credit, 4-week undergraduate
course in-residence, primarily in Corsham, Wiltshire, U.K. Students
explore the history of English landscapes and gardens in the context of
post-medieval British history. The course is team-taught every other
year by Purdue faculty from the Horticulture, History and Landscape
HORTSCIENCE, VOL. 40(4), JULY 2005
6/20/05 5:01:49 PM
Architecture programs. Excursions to landscape, garden and cultural
sites provide the primary basis for student discovery. Pretravel readings
and lectures prepare students for in-country, site-specific worksheets
and class discussions. Course philosophy, content, structure, logistics,
and instructional materials, which may be useful as a basis for course
development by educators at other institutions, are presented.
(148) A Lab Exercise to Enhance a Student’s
Understanding of Botany in Everyday Life using Fresh
Produce
Melinda McVey McCluskey*
University of Minnesota, Natural Resources Department, Crookston, MN, 56716
(149) Arizona Farm Safety Day
Glenn C. Wright*1, Stephen E. Poe2
1
University of Arizona, Plant Sciences, Yuma Mesa Agriculture Center, Somerton, AZ,
85350; 2University of Arizona, Agricultural and Biosystems Engineering, Yuma, AZ,
85366-6236
Arizona Farm Safety Day has been held annually since 2000 as an
attempt to educate students and farm workers (pesticide applicators,
tractor and equipment operators, irrigators, and field workers) in farm
safety. Our programs have emphasized tractor safety, pesticide safety,
ATV safety, electrical safety, and firearms safety. The all-day events
have been held in Yuma and in Safford, Ariz., and most of the attendees
are high school students. Agriculture students from six to eight high
schools typically participate. The agenda is determined by consulting
with local agriculture leaders. Attendees have the opportunity to attend a 4-hour training session in the morning. Subjects taught at these
sessions might include reading a pesticide label, sprayer calibration,
wearing proper protection, avoiding spray drift, tractor safety, and farm
safety. At least one of these sessions is an outdoors “hands-on” session.
Individual participants receive up-to-date information and literature, a
certificate of completion, CEUs, CCA credits, a hat, and a lunch. Spanish translation is available at each session. In the afternoon, a tractor
driver safety course and equipment demonstration is typically held. In
the course, selected representatives from local farms or local youth get
a chance to demonstrate their tractor and ATV driving and safety skills
for recognition and awards. Plaques and trophies are awarded to the
winners. Additionally, there is an equipment demonstration. Attendees
are tested before and after the event.
(150) Outcome Assessment of Resident Instruction: The
Colorado State University Experience
Harrison Hughes*, Elizabeth Mogen, Steven Newman, James Klett,
Anthony Koski
Colorado State University, Dept. of Horticulture & Landscape Architecture, Fort Collins,
CO 80524-1173
An assessment plan for the Horticulture and Landscape Horticulture
majors has been developed as part of a university-wide effort to assess
resident instruction. The program mission has been described as the
HORTSCIENCE, VOL. 40(4), JULY 2005
final6_20July HS.indb 1045
Poster Session 30—Floriculture: Mineral Nutrition/Pest
Management/Growth Regulators
20 July 2005, 12:00–12:45 p.m. Poster Hall–Ballroom E/F
(92) Effect of GA3 on Growth and Soft Rot Occurrence in
Zantedeschia (‘Black Magic’)
Chun-Woo Nam*1, Dong-Lim Yoo1, Su-Jeong Kim1, Jong-Taek
Suh1, Myoung-Rae Cho1, Kee-Yoeup Paek2
1
National Institute of Highland Agriculture, RDA, Horticultural Division, HoengGe-Ri 20,
Doam-Myon, PyongChang, GangWon-Province, 232-955, South Korea; 2Research Center
for the Development of Advanced Horticultural Technology, Chungbuk National University,
Horticulture, GaeShin-Dong 12, CheongJu, ChungBuk-Province, 361-763, South Korea
This experiment was carried out to determine correct applications of
GA3 for the production of cut flowers of Zantedeschia albomaculata cv.
Black Magic in highlands. Tubers were treated with GA3 in concentrations of 0, 100, and 200 mg·L-1. ABA contents in the tubers and roots
were twice as high (20~25 pmol/mL) in the control as in GA3-treated
tubers and roots. ABA content in roots increased with increasing GA3
concentration. Growth of the calla was investigated according to the
tuber hardness (3.3, 6.0 kg·cm-2), GA3 concentrations (0, 100, 200
mg·L-1), and GA3 treatment duration (24 h, 12 h, and 30 min before
planting). Tubers with higher tuber hardness were strong against soft rot,
regardless of the GA3 concentrations and treatment durations. Tubers
with lower tuber hardness showed over 90% soft rot occurrence when
treated with 200 mg·L-1 GA3 for 24 h before planting. However, soft
rot did not occur when treatment with 200 mg·L-1 GA3 was used for
12 h before planting.
POSTERS–WEDNESDAY
Students are often unable to relate the vegetables and fruits consumed
as a snack or part of a meal to the plant parts discussed in botany class.
Therefore, an exercise was developed for an introductory horticulture
course to increase a student’s awareness of botany in everyday life.
Fresh produce was brought in from local gardens, grocery stores,
or farmers markets. Vegetables and fruits were selected that are
consumed for their roots, stems, leaves, flower, fruit, and seeds. As
each vegetable or fruit was introduced, students named the plant and
plant part. As each part was identified it was “dissected” to show the
taxonomic features. The different fruit types, i.e., berry, hesperidium,
pepo, drupe, and pome were explained. Students were encouraged to
taste all vegetables and fruits as they were prepared. Most students
sampled the produce as it was passed around the group. Students easily recognized much of the produce, i.e., carrots, asparagus, tomatoes,
peas, oranges, and broccoli. The second part of the exercise exposed
students to vegetables and fruits that were unfamiliar. Most of the students had little exposure to the more exotic fruits and vegetables that
are now available. New vegetables and fruits that students said they
would add to their diet include jicama, pomegranate, and star fruit.
preparation of graduates with a passion for Horticulture/Landscape
Horticulture who can contribute to Colorado’s agricultural and green
industry economy through high levels of: 1) technical competency and
skills, including disciplinary competence, and a working knowledge
in the appropriate field; 2) management and leadership skills; and 3)
problem-solving skills. Assessment methods involved the development
of evaluation forms for internships, practicum, independent study, group
study, and the capstone courses. Student, faculty, clients, and industry
personnel used standardized forms, which varied somewhat for the two
majors and seven concentrations, to critically assess and score student
and faculty efforts. Internships, practicum, and capstone courses were
evaluated for program purpose. The management and leadership skills
of the students were evaluated based on their performance during internships by cooperators and also by their activities, as demonstrated
through their involvement in university, college, departmental, and
community activities. Problem-solving skills were evaluated primarily
through student performance in capstone courses, with specific criteria
in the internship and in leadership activities of clubs. The expectation
is that 70% to 75% of the students will score 3 or 3+ on all criteria
established for a rating system of 1–5. Students have generally met this
standard and plans are under way to continually upgrade courses and
related activities to improve the teaching program
(93) Evaluating the Effectiveness of Prohexadione-Ca
as a Plant Growth Retardant on Buddleia, Dianthus,
Eupatorium, and Lilium
Roberto G. Lopez*, Erik S. Runkle
1
Michigan State University, Horticulture, E. Lansing, MI, 48824
Prohexadione-Ca (ProCa) is a relatively new plant growth regulator
(PGR) that inhibits internode length in rice, small grains, and fruit trees.
However, little is known about its efficacy and potential phytotoxicity on
floriculture crops and how it compares to other commercially available
PGR chemicals. The effects of two foliar spray applications (2 weeks
apart) of ProCa (500, 1000, or 2000 ppm), paclobutrazol (30 ppm),
or a tank mix of daminozide plus chlormequat (2500 and 1000 ppm,
respectively) were quantified on Dianthus barbatus L. ‘Interspecific
Dynasty Red’, Ageratina altissima R. King & H. Robinson (Eupatorium rugosum) ‘Chocolate’, Lilium longiflorum Thunb. ‘Fangio’, and
Buddleia davidii Franch. ‘Mixed.’ All plants were forced in a glass-
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glazed greenhouse with a constant temperature setpoint of 20 °C under
a 16-h photoperiod. Two weeks after the second spray application of
ProCa at 500, 1000, or 2000 ppm, plant height of Dianthus and Lilium
was shorter than control plants by 56%, 60%, and 65% and by 6%,
26%, and 28%, respectively. However, ProCa bleached and reduced
the size of Dianthus flowers. ProCa at 2000 ppm and daminozide plus
chlormequat were effective at controlling the height of Eupatorium
(64% and 53% reduction, respectively); however, leaves of Eupatorium
were discolored and showed symptoms of phytotoxicity 1 week after
the first ProCa application. Only daminozide plus chlormequat were
effective on Buddleia. ProCa is an effective PGR for most of the crops
we tested; however, its discoloration of red flowers and foliage may
limit its application for commercial use.
(94) Efficacy of Application Methods and Concentration of
Plant Growth Retardants on Growth of Chrysanthemum
(Dendranthema ×grandiflorum ‘Cheasepeake’)
Chun Ho Pak1, Seung Won Kang1, Chiwon W. Lee*2
1
Korea University, Dept of Horticultural Science, A-nam Dong, Sung buk Gu, Seoul, 136701, South Korea; 2North Dakota State University, Department of Plant Sciences, Fargo,
ND, 58105-5051
Efficacy of application methods and concentration of plant growth retardants on growth of chrysanthemum (Dendranthema ×grandiflorum cv.
Cheasepeake) was tested. B-9 or cycocel (CCC) as a growth retardant
was applied as drench or subapplication with nutrient solution. In the
case of B-9 drench treatments, as B-9 concentrations increased, numbers
of flowers and flower buds increased except in the 1500-ppm treatment.
Increasing concentration of CCC also resulted in reduction of flower
numbers, total plant height, total leaf area, branch number, and fresh
weight. Reduction ratio of total plant height in 2000 ppm showed about
56.9% being compared to that of the 100-ppm drench treatment. B-9 or
CCC, combined with nutrient solution, was also supplied from the Cchannel subirrigation system. The B-9 subapplication treatment showed
no significance among these concentrations, but flower numbers, total
plant height, average plant height, and leaf numbers decreased as concentrations of CCC increased. B-9 or CCC with the same concentration
was drenched after 2 weeks of the first experiment to compare planting
time efficacy. Measured data increased until B-9 increased up to 2500
ppm and severe growth retardation resulted from the 5000-ppm treatment. Through this growth retardant application study, the combination
of drenching concentration and period of plant growth regulators (PGRs)
may result in effective growth retardation and reduction of application
concentrations for pot plant production.
(95) Black-eyed Susan (Rudbeckia hirta L.) as a Potted
Plant Crop in Response to Pinching and Paclobutrazol
Clydette M. Alsup, Pamela B. Trewatha*
Southwest Missouri State University, Agriculture, Springfield, MO, 65804
In two experiments, seedlings of black-eyed susan were transplanted into
15-cm pots and after 1 week received one of the following treatments:
media drench application of 0.1, 1, 10, or 100 mg·L-1 of paclobutrazol
or pinching back of terminal growth once, twice, or three times. After
plants reached salable size, plant height, lateral branch length and number, and flower counts were taken, and plants were harvested for dry
weights. In the first experiment, all pinching treatments and 10 mg·L-1
paclobutrazol reduced plant height and increased lateral branching.
Flower count at harvest was enhanced by paclobutrazol and reduced
by pinching, due to delayed development of inflorescences. Lateral
branching and flower bud count were greatest in the second study on
plants receiving three pinches. The 100 mg·L-1 paclobutrazol-drenched
plants had lowest height, dry weight, and bud count and were severely
stunted. The most attractive plants appeared to be those that received
the 10 mg·L-1 paclobutrazol drench treatments.
(96) Color Generation in Hydrangea Sepals as Controlled
by Metal Ion Complexes
Henry D. Schreiber*, Timothy Berry, Nam Trant
Virginia Military Institute, Department of Chemistry, Lexington, VA, 24450
The sepals of many hydrangea cultivars change color from red in
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basic/neutral soil to blue in acidic soil. This change is generally attributed to Al(III) becoming mobile in acidic soils, allowing it to be
absorbed through the roots as a citric acid complex; the ion of Al(III)
then forms a blue complex in the sepals with an anthocyanin that is
red in the absence of Al(III). This study investigated selected metal
ions that might also result in similar color changes in hydrangea sepals.
Model anthocyanins such as cyanidin and delphinidin glucoside readily formed blue complexes with metal ions with a high charge/size
ratio [that is: Mo(VI), U(VI), and Zr(IV), in addition to Al(III)]. The
anthocyanins only formed weak complexes with Fe(III) and Ga(III),
and no complexes with Mg(II) and Mn(II). In order for the color
change to occur in the sepals, though, the hydrangea must first be able
to selectively concentrate the metal ion in the plant from the soil as a
complex with citric or oxalic acid. The complexation of Al(III) with
the organic acid is shown by the measurement of the heat of solution
of citric and oxalic acid in Al(III) solutions as half that of the acids in
just water. The presence of Al(III) also enhanced the solubility of oxalic
acid in water. Mo(VI) likewise enhanced the organic acid’s solubility,
while Fe(III), Fe(II), and U(VI) did not appreciably affect the solubility.
Mo(VI) and similar ions may be candidates to artificially induce bluing
of hydrangea sepals, instead of the current use of Al(III).
(97) Screening Pythium sp. Associated with Greenhouse
Crops in Colorado for Mefanoxam Resistance
Miriam Fishell*, Laura Pottorff
Colorado State University, Cooperative Extension, Brighton, CO, 80601
Research was conducted on the fungus-like organism Pythium to observe its sensitivity to the fungicide Subdue MAXX, active ingredient
mefanoxam. Pythium is a plant pathogen that causes root and crown rot
in plants that are exposed to extensive soil moisture and poor drainage.
This study, conducted on Pythium isolated from Colorado greenhouse
crops, began in Apr. 2004. Symptomatic tissues from bedding plants
and perennials were placed on selective media (P10VP). Resulting
isolations of Pythium were transferred to cornmeal agar amended with
the recommended low and high label rates of mefanoxam. Mycelia
growth was monitored for 72 hours. Pythium sp. showing 20% growth
on amended mefanoxam agars, compared to the control growth, were
considered resistant to mefanoxam. Results from this study showed
that about 64% of the Pythium sp. isolated from greenhouse crops
in Colorado are resistant to mefanoxam. Data compiled from greenhouse integrated pest management surveys in Colorado show a high
dependence on the use of mefanoxam. Research and screening for
mefanoxam-resistant Pythium sp. will continue to provide Colorado
growers with effective control solutions for this pathogen.
(98) Impact of Selected Insecticides on Gas Exchange,
Vegetative and Floral Development, and Overall Quality
of Gerbera (Gerbera jamesonii var. ‘Festival Salmon’)
James D. Spiers*1, Fred T. Davies1, Chuanjiu He1, Carlos Bogran2,
Amanda Chau2, Kevin M. Heinz2, Terri W. Starman1
1
Texas A&M University, Horticulture, College Station, TX, 77840-2133; 2Texas A&M
University, Entomology
This research focused on the influence of insecticides on gas exchange,
chlorophyll content, vegetative and floral development, and overall
plant quality of gerbera (Gerbera jamesonii var. ‘Festival Salmon’).
Insecticides from five chemical classes were applied weekly at 1× and
4× the recommended concentrations. Insecticides used were: abamectin
(Avid® 0.15 EC), acephate (Orthene® Turf, Tree & Ornamental Spray
97), bifenthrin (Talstar® Nursery Flowable), clarified hydrophobic
extract of neem oil (Triact® 70), and spinosad (Conserve® SC). Phytotoxicity occurred in the form of leaf chlorosis on all acephate treatments, with the greatest damage occurring at the 4× concentration.
Photosynthesis and stomatal conductance were significantly reduced
in plants treated with neem oil extract. Plants treated with the neem
oil extract (1× and 4×) flowered later and had reduced growth [lower
shoot dry mass (DM) and total DM]. Plants that received 4× the recommended concentration of neem oil extract had reduced leaf area,
thicker leaves (lower specific leaf area), higher leaf chlorophyll content, and reduced flower production, as determined by flower number
HORTSCIENCE, VOL. 40(4), JULY 2005
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and flower DM. Plants treated with acephate 4× concentration were
the lowest quality plants due to extensive phytotoxicity (leaf burn),
which also reduced photosynthesis. The highest quality plants were
treated with spinosad and abamectin due to zero phytotoxicity and/or
no thrips damage (thrips naturally migrated into the greenhouse). The
control plants and plants treated with bifenthrin 1× were not marketable due to thrips damage; however, plant growth characteristics and
gas exchange were not statistically different.
Poster Session 31—Citrus
20 July 2005, 12:00–12:45 p.m. Poster Hall–Ballroom E/F
(459) Preliminary Evaluation of 17 Satsuma Mandarin
(Citrus unshiu Marco.) Cultivars in the Coastal Region of
California
ChihCheng T. Chao*
University of California-Riverside, Botany and Plant Sciences, Riverside, CA, 92521-0124
(460) De-greening of Early Season Satsumas in Louisiana
David Picha*1, Wayne Bourgeois2
1
Louisiana State University, Horticulture, Baton Rouge, LA, 70803; 2Citrus Research
Station, Horticulture, Port Sulphur, LA, 70083
Significant opportunities exist for expanding the marketing season
of Louisiana-grown satsumas. De-greening of the early season fruit
coupled with optimal storage conditions for the late season fruit may
allow for 6 months of market availability. Consumer demand in the
U.S. for specialty citrus, particularly easy peel seedless mandarins,
has increased in recent years. South Louisiana is one of the principal
satsuma production areas in the United States, with harvest beginning in
late September. Although the sugar : acid ratio of early season satsumas
may meet the state-mandated 10:1, peel color typically ranges from
green to greenish-yellow. Most consumers prefer a darker yellow-orange
peel color. Postharvest de-greening tests were conducted to determine
the appropriate method(s) and protocol for enhancing peel coloration
of early season harvested satsumas. Green peel satsuma fruit were
exposed to 0, 3, 5, 10, and 50 ppm ethylene for 12, 24, 36, and 48 hours
at 21 or 29 °C. An atmospheric ethylene concentration of ≥5 ppm for ≥24
hours at 29 °C provided optimal de-greening. However, peel darkening
in the form of irregular dark brown areas was observed after several
days in fruit exposed to ethylene concentrations of 50 ppm. Ethephon
was also an effective de-greening agent. Submersion of the fruit in 500
ppm ethephon for 30 seconds provided optimal de-greening. Buffering
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(461) Endocytic Uptake of Quantum Dots and Endocytic
Markers into ‘Sweet Lime’ Juice Cells
Ed Etxeberria*1, Pedro Gonzalez1, Javier Pozueta2
1
University of Florida, Citrus Research Center, Lake Alfred, FL, 33850; 2Nafarroako
Unibertsitate Publikoa eta CSIC, Agrobioteknologia eta Natura Baliabideetako Instituta,
Mutiloako etorbidea zenbaki gabe, Mutiloabeti, Nafarroa, 31192, Spain
To determine whether the mechanisms of sucrose accumulation into
the low acid ‘Sweet Lime’ (Citrus limmetioides Blanco) juice cells are
consistent with those previously reported for the more acidic cultivars,
we followed similar developmental changes in determinants of sink
strength. In addition, we followed the incorporation and distribution
of quantum dots and fluorescent endocytic probes into the cell with
time of incubation. As in other citrus fruits, sucrose levels, sucrose
synthase, sucrose phosphate synthase, and sucrose phosphate phosphatase increased throughout fruit development. The pH however,
was much higher than in the more acidic cultivars. Sucrose uptake
into energized plasmalemma vesicles was inhibited by gramicidin,
in accordance with the presence of an active symport mechanism of
sucrose from the apoplast into the cytosol. On the contrary, tonoplast
vesicles were shown to lack active transport mechanism of sucrose
into the vacuole. In conformity with recent findings showing the occurrence of an endocytic mechanism in ‘Murcott’ mandarin, ‘Sweet
Lime’ juice cells were shown to incorporate membrane-impermeable
dyes into their vacuoles in the presence of sucrose. High-definition
confocal microscopy revealed the co-localization of membraneimpermeable markers in cytoplasmic vesicles, in membrane-bound
intermediate structures such as the endosome and multi-vesicular
body, and the eventual distribution of such fluorescent particles. The
data provide strong evidence for an endocytic system of transport
that allows direct incorporation of sucrose from the apoplast to the
vacuole and for the visualization of intermediate distribution and
cargo centers in the cell.
(462) Citrus and Its Putative Bioactive Limonoids:
Beneficial Effects on Bone Strength
Kranthi Kiran Mandadi*1, G.K. Jayaprakasha1, Farzad Deyhim2,
Bhimanagouda S. Patil3
1
Texas A&M University–Kingsville, Citrus Center, Agronomy and Resource Sciences,
Weslaco, TX, 78596; 2Texas A&M University–Kingsville, Citrus Center, Human Sciences, Welasco, TX; 3Texas A&M University, Vegetable and Fruit Improvement Center,
Department of Horticultural Sciences, College Station, TX, 77845
POSTERS–WEDNESDAY
The citrus industry in California is changing, and growers are planting
more easy-peeling, seedless, and nice-tasting mandarins. Our industry tries to develop new early- and late-season mandarin cultivars to
be competitive in the global mandarin market. Seventeen satsuma
mandarin (Citrus unshiu Marco.) cultivars were top-worked onto 4–6
Valencia orange [C. sinensis (L.) Osbeck] as interstocks and Carrizo
citrange [C. sinensis (L.) Osbeck × Poncirus trifoliata (L.) Raf.] as
rootstocks in 30 May 2001 near Santa Paula, Calif. All trees set the
first crop in Fall 2003. Fruit maturity of all cultivars was measured
based on °Brix level, percent acid, and S:A ratio on a weekly basis
since the first week of Sept. 2004. Five cultivars, ‘Armstrong’, ‘KunoWase’, ‘Miyagawa’, ‘S9’ and ‘Xie-Shan’ (‘Wakiyama’), are very
early- or early-season cultivars. A small-scale degreening experiment
with 72 h treatment of 0.5 mg·L–1 ethylene with fruit harvested on 6
Oct. 2004 also showed the rind color of all five cultivars could be
enhanced nicely. ‘Miyagawa’ had very intense internal orange flesh
color visible in the second week of Sept. 2004, comparing with other
cultivars. All these five cultivars could potentially become early-season,
completely seedless, and easy-peeling satsuma cultivars in California.
‘Miyagawa’ and ‘Xis-Shan’ could potentially be harvested as early
as from late September to early October in the central coastal region
and from late August to mid-September in the San Joaquin Valley.
Both cultivars should command a high price when there is no seedless
mandarin in the market.
of the submersion solution pH had no effect on de-greening
effectiveness.
Citrus proved beneficial to human health in preventing cardiovascular
disorders, hypertension, anemia, and several cancers, including colon,
lung, skin, stomach, and breast, in animal and cell culture studies. For
the first time, current study was focused to determine whether orange
juice and grapefruit juice increase bone mass in an orchidectomized
(ORX) rat model of osteoporosis. Thirty-six male Sprague-Dawley
rats were randomly divided into four groups of 1) sham; 2) ORX; 3)
ORX + orange juice (OJ); and 4) ORX + grapefruit juice (GJ). All
rats were fed to the mean intake of the sham group and were provided
with freshly squeezed grapefruit or orange juice for 60 days. There
was a numerical improvement in femoral density with OJ and GJ
compared to the ORX group. Ultimate bone strength and femoral
cortical area diameter (mm) increased (P < 0.05) with OJ and GJ
compared to the ORX group. Furthermore, bone fracture withstand
threshold time(s) increased (P < 0.05) with OJ and GJ compared to
the ORX group. Beneficial effects of citrus juices on bone strength
could be related to its bioactive triterpene compounds and nutrient
composition. Isolation of triterpenes using specific combinations of
food-grade adsorbent and ion exchange resins yielded pure limonin17-β-D-glucoside and limonin along with obacunone, nomilin, and
deacetylnomilin. Identification and characterization of the isolated
limonoids were performed by specific analytical techniques, such as
HPLC, LC-MS, and NMR. Further studies are needed to determine
the protective effects of limonoids on bone homeostasis. Funded by
USDA 2001-52102-11257 and 2004-34402-14768.
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6/20/05 5:01:53 PM
(463) Grapefruit Crop Load Affects Net Gas Exchange of
Leaves, Tree Growth, and Fruit Quality
Kuo-Tan Li*, Jim Syvertsen, Jill Dunlop
University of Florida, IFAS, Citrus Research and Education Center, Lake Alfred, FL,
33850
Effects of crop load on leaf characteristics, shoot growth, fruit shape,
fruit quality, and return bloom were investigated in 13-year-old ‘Ruby
Red’ grapefruit (Citrus paradisi Macf.) on ‘Swingle’ citrumleo rootstock. Trees were hand thinned in June 2003 and 2004 at the end of
physiological fruit drop to establish three to four levels of crop load
ranging from normal (high crop load without thinning) to extremely
low (near 90% fruit removal). Leaves on high crop load trees had higher
net assimilation of CO2 (ACO2) than those on low crop load trees. Crop
load enhancement of ACO2 continued until harvest. In 2004, however,
the effects were diminished in October just prior to the beginning of
the harvest season, after leaf and fruit loss from three consecutive
hurricanes. There was no difference in leaf dry weight per leaf area
and leaf nitrogen among treatments. Nonfruiting branches of high crop
load trees produced fewer, but longer, summer flushes than those of
low crop load trees. Fruiting branches generally produced few summer
flushes with similar shoot lengths among treatments. High crop load
trees developed a greater percentage of vegetative shoots, whereas low
crop load trees developed more inflorescences. Crop load adjustments
did not affect fruit size and total soluble solid content, but low crop
load trees produced a higher percentage of irregular shape (sheepnosed)
fruit with high acidity.
(464) Temperature Relationships in a Mature Orange
Orchard between Areas with or without a Partial
Permanent Cover Crop
Neil V. O’Connell*1, Craig E. Kallsen2, Richard L. Snyder3,
Blake L. Sanden2, Paul W. Giboney4, Mark W. Freeman5
1
University of California, Cooperative Extension Tulare Co., Tulare, CA, 93274-9539;
University of California, Cooperative Extension Kern Co., Bakersfield, CA, 93307;
University of California, Davis, LAWR, Hoagland Hall, Davis, CA, 95616;4Columbine
Vineyards, Delano, CA, 93215-9597; 5University of California, Cooperative Extension,
Fresno, CA, 93702
2
3
Many citrus growers are hesitant to plant cover crops, particularly
perennial types, because of possible increased frost hazard. To quantify
the increased risk, temperature relations over a 3-year period were compared between areas in a ‘Valencia’ orange orchard with and without a
partial perennial cover crop. The partial perennial cover crop consisted
of a mowed perennial planting along the double drip line hoses, and an
annually fall-replanted unirrigated strip of groundcover in the middle
between the tree rows. This partial perennial cover crop increased the
frost hazard compared to uncultivated bare ground even when wind
machines were operating.
Poster Session 32—Nursery Crops 2
20 July 2005, 12:00–12:45 p.m. Poster Hall–Ballroom E/F
(99) Development of an Ohio Tree Liner Production
System in Retractable Roof Houses; Field Comparisons
with West Coast-grown Liners
Hannah M. Mathers, Elizabeth Grosskurth*, Michele Bigger, Luke
Case, Jenny Pope
The Ohio State University, Horticulture & Crop Science, Columbus, OH, 43210
Currently, the majority of tree liners used in the Ohio nursery industry
are imported, mainly from the West Coast. The Ohio growing season
is 156 days, whereas the Oregon season is 225 days. We are developing an Ohio liner production system, utilizing a retractable roof
greenhouse (RRG) that extends the growing season. Liners grown
in a RRG have shown greater caliper, height, and root and shoot dry
weight than those grown outside of a RRG (Stoven, 2004). The objective of this research was to compare the growth of RRG-grown liners,
outdoor-grown liners, and West Coast-grown liners when planted in
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final6_20July HS.indb 1048
the field. Four tree species [Quercus rubra, Malus ‘Prairifire’, Acer
×freemannii ‘Jeffersred’ (Autumn Blaze®), and Cercis canadensis]
were started from either seed or rooted cuttings in early 2003. They
were grown in a glass greenhouse and then moved to their respective
environments in March (RRG) and May (outside). In Oct. 2003, the
Ohio-grown liners were planted in the field at the Waterman Farm of
The Ohio State University, Columbus. In Spring 2004, liners from
the West Coast were purchased and planted in the same field setting.
Caliper and height were measured in June and Sept. 2004. After one
season in the field, trees grown from the RRG and outdoor environments resulted in greater height and caliper than the West Coast liners
in Malus, Acer, and Cercis. Acer liners from Oregon had a greater
increase in height from June to September than those grown outdoors
or in the RRG. Quercus liners from the RRG and outdoor environments
displayed greater caliper growth and growth in height than those from
the West Coast. Across all species, liners grown from the RRG had
the greatest increase in caliper growth.
(100) Use of Raw and Composted Paper Mill Sludges,
Municipal Waste Composts, and Other Waste Ingredients
in Container Nursery Substrates
Calvin Chong*, Peter Purvis
University of Guelph, Plant Agriculture, W, Guelph, Ontario, N1G 2W1, Canada
Plug-rooted liners of deutzia (Deutzia gracilis), dogwood (Cornus alba
‘Argenteo-marginata’), forsythia (Forsythia ×intermedia ‘Lynwood
Gold’), and ninebark (Physocarpus opulifolius) were grown in 6-L
containers. There were 36 different treatment substrates formulated
in factorial combinations: two types of paper mill sludge (raw or
composted) each at three rates (25%, 33%, or 50%, by volume)
mixed with one of three sources of municipal waste compost (cities of
Guelph, Toronto, or Waterloo; 25%, 33%, or 50%), and the remainder
consisting of one of two base supplements (pine bark or 1-year-old
wood chips; 50%, 33%, or 0%). The containers were trickle-irrigated
and fertilized with a controlled-release fertilizer. Dogwood (no treatment interaction and responding only to the main effect of compost
sources) grew equally well with Toronto and Waterloo composts, but
less well with the Guelph compost. Ninebark tended to grow better
with Toronto compost, intermediate or similar with Waterloo compost,
and least with Guelph compost. Forsythia grew equally well in all
bark-based substrates, regardless of sludge type and rate or compost
source. With wood-chip-based substrates, however, forsythia grew
better with Waterloo than with Guelph compost, and better with raw
than with composted sludge when mixed with Toronto compost.
Deutzia responded similarly to most substrates, but grew marginally
better with raw than with composted paper sludge when Waterloo or
Toronto compost was present. Despite these differences in species
responses, all plants were of marketable size at the end of the season.
There was no sign of nutrient toxicity or deficiency due to any of the
substrates.
(101) Fertilizer Source Affects Nitrogen and Phosphorus
Levels in Leachate from Container-grown Quercus
phellos L. and Magnolia virginiana L.
Donna C. Fare*
USDA-ARS, Floral Nursery Plant Research Unit, McMinnville, TN, 37110
Environmental concerns with nitrogen and phosphorus use at container
nurseries and the subsequent effects of nutrient-laden irrigation effluent prompted this study. Bare root liners of willow oak (Quercus
phellos L.) and sweetbay magnolia (Magnolia virginiana L.) were
grown in #5 containers during year one and repotted into #15 containers during year two using 100% pine bark or pine bark : peat substrate
(4:1 by volume). Two fertilizer sources, Osmocote 19N–2.2P–7.5K
(19–5–9) or Harrell’s 17N–2.2P–10.0K (17-5-12), were included in
the container substrate in a fluoropolymer bag with 17 g N in each #5
container and 63 g N in each #15 container. Using a split plot design
with fertilizer and media as subplots, a cyclic irrigation regime consisting of three irrigation applications spaced one hour apart was compared to a traditional irrigation regime with one irrigation application
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6/20/05 5:01:55 PM
that equaled the total volume applied in the cyclic regime. Fertilizer
source influenced cumulative amounts (mg/year) of ammonium-N,
nitrate-N and orthophosphate in the container leachate. Nitrate-N and
ammonium-N from Harrell’s 17N–2.2P–10.0K fertilizer were each
≈20% higher in the container leachate from sweetbay magnolia than
Osmocote 19N-2.2P-7.5K fertilizer. In the case of the willow oak,
the differences were 32% and 19%, respectively. Orthophosphate
averaged about 65% greater in leachate from both sweetbay magnolia
and willow oak containers when grown with Osmocote compared to
Harrell’s fertilizer. At the end of year two, height and caliper growth
were similar among treatments with both species.
(102) Monitoring Nutrient Mitigation at a Container
Nursery Wetland: A 3-Year Study
Milton D. Taylor1, Sarah A. White1, Stephen J. Klaine1,
Ted Whitwell*2
1
Clemson University, Clemson Institute of Environmental Toxicology, Pendleton, SC,
29670; 2Clemson University, Department of Horticulture, Clemson, SC, 29634-0375
(103) Screening Landscape Plants for Their Ability to
Accumulate Nitrogen and Phosphorus
Robert F. Polomski1, Milton D. Taylor2, Sarah A. White2,
Ted Whitwell*1, Stephen J. Klaine2, William C. Bridges, Jr.3
1
Clemson University, Horticulture, Clemson, SC, 29634-0319; 2Clemson University,
Clemson Institute of Environmental Toxicology and Biological Sciences, Pendleton,
SC, 29670-0709; 3Clemson University, Applied Economics and Statistics,Clemson, SC,
29634-0367
Commercial nurseries use large amounts of water and nutrients during
production cycles. Runoff contaminated with N and P can adversely
impact surface and groundwater quality. A 3-year monitoring study
of nutrient mitigation by a constructed wetland at a container nursery
found nitrogen removal was highly efficient. However, orthophosphateP removal was highly variable. Partial removal occurred during some
months, but net export also occurred. P levels in wetland discharge—between 0.84 and 2.75 ppm—were well above the generally accepted
level for preventing downstream eutrophication. Therefore, identifying
landscape plants that remediate nutrients, especially P, could be useful
in improving constructed wetlands. A 2003 greenhouse study screened
commercially available landscape plants for their phytoremediation
potential. Among the 17 taxa and 19 cultivars examined were woody
shrubs, e.g., Cornus amomum, Myrica cerifera ‘Emperor’, and Salix
integra ‘Hakura Nishiki’; herbaceous semiaquatics, e.g., Canna (two
cultivars), Colocasia esculenta ‘Illustris’, Rhyncospora colorata,
Iris ‘Full Eclipse’, Pontederia cordata ‘Singapore Pink’, and Thalia
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(104) Green Ash (Fraxinus pennsylvanica) Response to
Nitrogen Rate and Timing in a Field Nursery
Catherine Neal*
University of New Hampshire, Plant Biology, Durham, NH, 03824
Bare-root, 4-ft whips of green ash (Fraxinus pennsylvanica ‘Marshall’s
Seedless’) were planted in June 2001 in a randomized complete-block
design with three trees per plot. An incomplete factorial design was
used to test whether annual fertilizer rate and/or application dates affected growth. Treatments were fertilized from 0 to 4 times per year in
mid-April, mid-June, mid-August, and/or mid-October. A rate of 1 lb
of nitrogen (N)/1000 sq ft was used whenever fertilizer was applied
to a plot. Each treatment received 0, 2, 3, or 4 lbs N/1000 sq ft/year
depending on the number of applications. Caliper, height, and terminal
growth were measured annually for three growing seasons. At the end
of seasons 2 and 3, one plant per plot was destructively harvested and
processed to obtain dry weights of shoots and roots, and the shoot to
root ratio was calculated. Data were analyzed by analysis of variance
with least square means contrasts. Treatment effects on top weights,
root weights, and shoot to root ratios were nonsignificant. There were
significant treatment differences for caliper and terminal growth in
years 1 and 2, but not 3. A set of orthogonal contrasts was used to
determine that the effect was due primarily to growth differences in
plants receiving 2 vs. 3 or 4 lbs N/1000 sq ft/year, but that 3 vs. 4 lbs
made no difference. Another set of planned, but nonorthogonal contrasts was used to compare application date effects. Plants fertilized
in June were greater in caliper and terminal growth in the first 2 years
than plants not fertilized in June. There were nonsignificant effects of
fertilizing vs. not fertilizing in late fall or early spring.
(105) Holding Bareroot Colorado Spruce Trees in a
Gravel Bed
Robert R. Tripepi*, Mary W. George, John E. Lloyd
University of Idaho, Horticultural Sciences Division, PSES, Moscow, ID, 83844-2339
POSTERS–WEDNESDAY
Container-grown plants require large amounts of water and nutrients
during their production cycle. This results in substantial runoff that
is contaminated with nitrogen and phosphorus. At our study site,
nutrients were delivered through incorporation in the potting media
as timed-release prills and through liquid feeding by injection into
irrigation water. Mitigation of nutrients in runoff water was dealt with
proactively by the container nursery with construction of 3.77 ha of
planted wetlands to receive runoff from a 48.6-ha drainage basin and
excess water diverted from adjacent watersheds. Water flowed though
drains between wetland cells and eventually into stilling ponds before
it was allowed to exit the property. Water flow through the wetlands
ranged from 1.1 to 3.1 million liters per day over the period. Three
years of monitoring data indicate some seasonal differences in nitrogen removal efficiencies. Nitrogen removal between March and
November averaged ≥95% while removal during winter (December
through February) averaged ≥72%. Nitrogen (as nitrate) varied from
4.28 ppm to ≤0.01 ppm in wetland discharge, well below drinking
water quality standards, but occasionally above levels that may cause
downstream eutrophication. Orthophosphate phosphorus removal was
highly variable with greatest removal occurring during late spring,
late fall, and winter. There was a significant net export of phosphorus
during some summer months for years 2 and 3. Phosphorus levels in
wetland discharge ranged between 0.84 and 2.75 ppm. While there is
currently no legal water quality standard for phosphorus, these levels
were above the generally accepted level for preventing downstream
eutrophication.
geniculata ‘Red Stem’; and floating aquatics, e.g., Myriophyllum
aquaticum, Eichhornia crassipes, and Pistia stratiotes. Plants were
grown in pea gravel media and kept saturated with one of five concentrations of Hoagland’s. Herbaceous and woody plants were harvested
after 8 and 13 weeks, respectively. Experiments were replicated twice
for each cultivar. The nutrient uptake efficiency was determined for
each taxon from the total amount of N and P applied and the biomass
dry weight and N and P content.
Field-grown conifers are usually discarded if their root balls break
during digging, but using an alternative holding system until the root
systems recover could reduce production losses. The objective of
this study was to determine if a gravel bed could be used as a holding treatment for 1.5- to 1.8-m-tall Colorado spruce (Picea pungens)
trees that had soil removed from their root systems in the spring. Root
systems from 12 trees were washed free from pine bark mulch and soil
before the trees were randomly assigned to a gravel bed. One bed held
a mixture of 88% pea gravel (1-cm minus), 2% Turface®, and 10%
silica sand (by volume). The other bed contained a mixture of 90%
basalt gravel (1.2-cm) and 10% sand. Trees were grown in the gravel
beds for 5 or 6 months before height increases were determined. If
the terminal leader died on the tree, the next highest lateral branch
was measured for its increase in length. All trees survived and actually grew a little during the summer after removing all the soil from
their root systems. Several trees suffered slight needle burning at the
ends of random branches, but the damage appeared minimal. Tips
of several small branches randomly located around the canopies on
several trees died back, and up to 10 cm of the terminal leaders on
about half the trees died back. Height increases were similar among
the different trees grown in the two types of gravel, with the mean
increase in height being 8.9 cm. The trees regenerated many roots in
both types of gravel. In fact, new roots formed all over the root systems
and encased large amounts of gravel, making its removal difficult.
This study demonstrated that gravel beds can be used to help 1.8-m
tall Colorado spruce trees recover from severe root losses.
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(106) Improved Root Growth of Corkbark Fir and Pinyon
Pine Seedlings Grown in a Gravel Bed
Robert R. Tripepi*, Mary W. George
University of Idaho, Horticultural Sciences Division, Moscow, ID 83844-2339
Seedlings of several conifer species can be difficult to transplant, with
the problem often related to poor root regeneration. The objective of
this study was to determine if corkbark fir (Abies lasiocarpa arizonica)
seedlings or pinyon pine (Pinus edulis) seedlings would produce more
root growth when grown in a Missouri gravel bed growing system
compared to field soil. The 3–0 fir seedlings and 4–0 pine seedlings
were planted in a gravel bed in mid-April. The gravel bed was 3 m ×
3.7 m and was filled with a mixture of 60% pea gravel (1 cm minus),
30% Turface®, and 10% silica sand (by volume). A field bed 3 m × 3.7
m in size was also prepared. Fir seedlings were harvested in September
and October, but pinyon pine seedlings were harvested only in October
due to their poor transplant survival. Plant heights, stem diameters, and
root volumes, as well as root and shoot dry weights, were determined
at harvest. Of all the measured growth parameters for both species,
only root dry weights and root volumes were significantly different. In
particular, fir seedlings grown in the gravel bed produced at least 30%
more root dry weight and 74% more root volume than those planted
in field soil whether plants were harvested in September or October.
Likewise, pine seedlings grown in gravel produced at least 37% more
root dry weight and 86% more root volume than those grown in soil.
In addition, only 10.6% of the pine seedlings planted in soil survived
transplanting, but 23.3% of those grown in the gravel bed survived.
This study demonstrated that corkbark fir and pinyon pine seedlings
grown in a gravel bed produced larger root systems than those planted
into field soil, and the gravel bed also improved pinyon pine seedling
survival after transplanting.
(107) Effects of Defoliants (CuEDTA and ZnSO4) and
Foliar Urea on Defoliation and Nitrogen Reserves of
Almond Nursery Plants
Guihong Bi*1, Carolyn Scagel2, Leslie Fuchigami1
1
Oregon State University, Horticulture, Corvallis, OR, 97331; 2USDA–ARS, Horticultural
Crops Research Unit, Corvallis, OR, 97330
One-year-old field-grown ‘Nonpareil’/’Nemaguard’ and ‘Nonpareil’/
‘Lovell’ almond nursery trees were used to study the effects of chemical defoliants (CuEDTA and ZnSO4) and foliar applications of urea on
defoliation and nitrogen (N) reserves. Although both chemical defoliants
significantly promoted earlier defoliation, CuEDTA was more effective
than ZnSO4 in promoting early defoliation. Two applications of defoliant
had a similar effect as one application on promoting leaf abscission.
Foliar applications of urea in addition to defoliant applications (urea
+ defoliant treatments) generally increased the efficiency of ZnSO4
(1.25% to 2%) and CuEDTA (0.5%) in promoting early defoliation.
Although treatments with only defoliants did not consistently lower
N reserve levels, trees treated with foliar urea or urea + defoliants had
significantly higher nitrogen reserves compared to trees receiving only
defoliant treatments. N reserves were comparable in urea + defolianttreated trees to the levels found in naturally defoliated (control) trees.
We conclude that both CuEDTA and ZnSO4 are effective in promoting
early defoliation of almond nursery trees. Combining urea with defoliants
can effectively promote early defoliation and is important for achieving
N reserves similar to naturally defoliated trees.
mutation (mut11) under control of a ubiquitin promoter was inserted
using biolistics into two Dendrobium varieties with the intention of
creating CymMV-resistant orchids. Presence of the transgene in regenerated plants of D. × Jaquelyn Thomas ‘Uniwai Mist’ and D. x Jaq
– Hawaii ‘Uniwai Pearl’ was confirmed by PCR using genomic DNA,
and mut11-positive plants were potted ex vitro. Forty-two transgenic
plants and four non-transgenic control plants at the 4- to 6-leaf stage
were inoculated with a 1:1000 dilution of CymMV obtained from
infected orchids. Plants were analyzed for systemic infection using
tissue blot immunoassay (TBIA). Seventeen plants from at least six
independent transformations remained virus-free, whereas all control
plants were infected with CymMV within 1 month. Further analysis
by RT-PCR showed that the mut-11 mRNA was detectable in only
two of these 17 plants. All plants were challenged again with a second
CymMV inoculation as above, followed by TBIA analysis after 1 month.
Thirteen of 17 plants remained free from virus. A third challenge of
these plants with CymMV as above was followed by TBIA analysis at
1 week, 2 weeks, 1 month, 3 months, 6 months, and 12 months after
challenge. Results at 2 weeks post-inoculation showed that all six
controls and four individual transgenic plants, including the RT-PCRpositive plants, became systemically infected. Nine transgenic plants
from both varieties remained free from CymMV 12 months after the
third challenge. Lack of detectable mut11 mRNA in these resistant lines
suggests that a post-transcriptional gene silencing (PTGS) mechanism
may be conferring resistance to CymMV.
(279) Morinda citrifolia In Vitro Seminal Germination,
Callus and Organogenesis Induction
Michael J. Tanabe*, Nicole Wakida
University of Hawaii at Hilo, College of Agriculture, Forestry and Natural Resource
Management, Hilo, HI, 96720-4091
Noni, Morinda citrifolia, is receiving a lot of attention for its potential
medicinal effects. Hawaii is an ideal growing environment for this
plant, where it has been used for many purposes, including medicinal
ones, by ancient Polynesians. Currently, there is a rapidly developing
noni industry in the state of Hawaii. Propagation of this plant is almost
exclusively by seeds, and germination generally requires a couple of
months without preconditioning or about a month if mechanically
scarified. We developed an in vitro protocol that significantly improves
percent germination rate by altering incubation temperature and the
in vitro culture basal medium. Germination time was decreased to 4
days when the embryo was extracted and exposed to 31 °C. A basal
medium containing 1/2 Murashige and Skoog (M&S) salts was the
most effective in reducing germination time and increasing percent
germination. Stem pieces obtained from in vitro-propagated seedlings
produced callus when explanted in 1/2 M&S containing various levels
of naphthalene acetic acid (NAA). The most effective treatment was
0.5 μM NAA and the least effective treatment was 2 μM NAA. Treatments without NAA did not produce callus. Calli treated with 4.40 μM
6-benzylaminopurine (BA) or 8.80 μM BA were the most effective in
promoting caulogenesis. We also demonstrated that the number of first
generation seedlings produced from each embryo could be increased
by treatment with 8.80 μM BA.
(280) Plant Regeneration of Periwinkle (Catharanthus
roseus) from In Vitro Leaf Tissues
Wenhao Dai*, Victoria Jacques
North Dakota State University, Plant Sciences, Fargo, ND, 58105
Poster Session 33—Plant Biotechnolgy 3
20 July 2005, 12:00–12:45 p.m. Poster Hall–Ballroom E/F
(278) Virus Resistance in Orchid Plants Transformed with
a Mutated Movement Gene of Cymbidium mosaic virus
Kullanart Obsuwan*1, Wayne B. Borth2, John Hu2,
Adelheid R. Kuehnle1
1
University of Hawaii, Tropical Plant and Soil Sciences, Honolulu, HI, 96822 2University
of Hawaii, Plant and Environmental Protection Sciences, Honolulu, HI, 96822
A Cymbidium mosaic virus movement protein gene with a site-specific
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Periwinkle, a perennial commonly used as a summer bedding plant,
is known as the source of vinca alkaloids used to treat lymphocytic
leukemia and Hodgkin’s disease. It is also one of the natural hosts of
many phytoplasma diseases, such as X-disease of major Prunus species, aster yellows, and ash yellows diseases. Therefore, periwinkle
is an ideal plant species for phytoplasma disease research, such as
disease transmission, species resistance, and resistant gene screening.
Periwinkle tissue culture was established by incubating sterile seeds in
hormone-free Murashige and Skoog (MS) medium. Plants were successfully regenerated from in vitro leaf tissues of periwinkle. Adventitious
shoots were induced when leaf tissues were cultured on Murashige and
HORTSCIENCE, VOL. 40(4), JULY 2005
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Skoog (MS) medium or woody plant medium (WPM) supplemented
with benzyladenine (BA) and naphthaleneacetic acid (NAA). Nearly
75% of leaf explants produced shoots in both media with 10–20 μM
BA and 1 μM NAA. A mean of 4.3 shoots was produced from each
explant cultured on WPM, whereas only 2 shoots were produced on MS
medium under 16-h photoperiod. Leaf explants under dark treatment
for 2 weeks produced big callus only, indicating that light is necessary
for shoot formation. Most adventitious shoots were induced from the
joint of leaf blade and petiole. In vitro shoots (>1.5 cm) were easily
rooted in half-strength MS medium. Addition of NAA dramatically
increased root number, with more than 20 roots being induced in 5
μM NAA medium. Rooted plants were transferred to potting medium
and grown in a greenhouse.
(281) Effects of Colchicine and Oryzalin on Callus and
Adventitious Shoot Formation of Euphorbia pulcherrima
‘Winter Rose’™
Kimberly A. Pickens1, (Max) Zong-Ming Cheng*2,
Stephen A. Kania3
1
Macon Sate College, Natural Sciences & Math, Macon, GA, 31206; 2University of Tennessee, Department of Plant Sciences, Knoxville, TN, 37996; 3University of Tennessee,
Department of Comparative Medicine, Knoxville, TN, 37996
(283) Petal Color Changes in Carnation Plants
Transformed with an Antisense DFR and a CHI Gene
Kyung Hee Hwang1, Byung Hwan Min2, Haki Shin3,
Byung Joon Ahn*1
1
Dankook University, Ornamental Horticulture; 2Nong Woo Bio Co., Ltd, Bio Res Institute,
Yeoju, Kyunggido, 469-880, Korea; 3National Horticultural Research Institute, RDA,
Floriculture, Suwon, 440-760, Korea
To produce transgenic carnation plants expressing modified flower
colors, cultivars of red-flowering carnation (‘Desio’ and ‘Garnet’) were
transformed with a antisense DFR gene encoding dihydroflavonol-4reductase, and yellow-flowering carnations (‘Pallas’ and ‘Keumbyul’)
were introduced with a CHI gene encoding chalcone synthease isomerase. Explants of leaves, stems, and shoot tips were inoculated with
Agrobacterium and grown overnight in induction broth supplemented
with 0.2 mM acetosyringone. The cocultures of carnation explants
were maintained in the light at 24 °C on one-half strength MS medium
solidified with 0.3% Gelite and supplemented with 1.0 mg·L-1 BA for
10 days, and then were transferred to a selection medium containing
250 mg·L-1 cefotaxime/carbenicillin, 500 mg·L-1 kanamycin. They
were subcultured every 2 weeks for over six times and regenerated.
In ‘Garnet’ and ‘Desio’ carnation cultivars, a total of 146 plants was
transformed with anti-sense DFR gene in pGA748/LBA4404. In yellow flowering cultivars ‘Pallas’ and ‘Keumbyul’, transformed with
CHI gene in pGA748/LBA4404, 20 putative transformants obtained.
The introduction of the transgenes were confirmed through PCR and
flower color changes. Rates of phenotypic expression of the transgene,
antisense DFR gene, vary among the transformants such as lighter
pigmentation or chimeric discoloration, more prominently in outer
petals of the flowers. Transgenic plants of chi gene bloomed flowers
of lighter yellow petals in general. The most prominent phenotypic
changes were discoloration of red strips on petals, which are typical
characteristics of the cultivars.
(284) Characterization of the Genus Corylopsis
Mark S. Roh*1, Eunju Cheong1, Ik-Young Choi2, Eun-Ha Yoo3,
Jae-Young Kim3, Nam Sook Lee4
POSTERS–WEDNESDAY
Poinsettia, Euphorbia pulcherrima, is an important holiday symbol
and is the number one flowering potted plant in the United States. The
technique of chromosome doubling has been utilized to increase size
of flowers, stems, and leaves of many species, and has been used in
poinsettia breeding to obtain new cultivars. Application of colchicine
or oryzalin to in vitro tissues may be used to enlarge the inflorescences
and brackets and reduce the height of ‘Winter Rose’™ poinsettias, reduce
the likelihood of chimeric tetraploids, and provide a rapid means for
producing many tetraploid plants. The purpose of this research was to
evaluate the effect of colchicine and oryzalin on callus and adventitious
shoot formation of ‘Winter Rose’™ poinsettia with in vitro grown leaf
tissues and its potential for tetraploid induction. In vitro grown leaf
midvein sections were placed on various media supplemented with
either colchicine or oryzalin at various concentrations for 1–4 days.
Colchicine was least damaging to leaf tissues at concentrations of 0.25
or 250.4 μM. A large amount of callus, as well as adventitious shoots,
were produced. Regenerated shoots were found to be diploid, determined by flow cytometry. On media with oryzalin (28.9–144 μM), leaf
tissues produced callus, but not adventitious shoots. Calluses produced
on oryzalin-containing media were tested using the flow cytometer and
were found to be diploid.
alone or picloram as auxin source. After 16 weeks of culture, calli were
transferred to SI medium, supplemented with three different concentrations of thidiazuron (TDZ), either intact or subdivided (150 mg/explant).
SI treatments had a greater and significant response when the callus
came from a CI medium containing auxin and cytokinin combined, in
comparison to those coming from a CI medium containing auxins only.
1
(282) In Vitro Indirect Organogenesis of Leucocoryne
purpurea, an Ornamental Geophyte Species Endemic to
Chile
Luis Humberto Escobar Torres*, Eduardo Alejandro Olate Muñoz,
Miguel Jordan, Marlene Gebauer
Pontificia Universidad Católica de Chile, Horticulture, Vicuña Mackenna #4860, Santiago,
Región Metropolitana, Chile
Callus induction (CI) and later shoot induction (SI) were studied in
Leucocoryne purpurea, a native and endemic Chilean geophyte species.
Basal leaf portions (BL), bulb basal plate (BP), and root tips (RT) from
in vitro plants were used as explants. Treatments for CI included all
three explants and media containing different sources and concentrations of auxins and cytokinins as plant growth regulators (PGRs). Plant
material was initiated on MS basal medium (Murashige and Skoog,
1962), supplemented with vitamins, 30 g·L-1 sucrose, 6.0 g·L-1 agar and
pH adjusted to 5.7 before autoclaving. The experiments were carried
on a growth chamber at 24 ± 1.5 °C. CI cultures were maintained in
darkness for 16 weeks, and SI for 12 weeks in a 16-hour photoperiod.
BL and RT explants did not respond to any of the CI treatments. BP
explants cultured on MS basal medium without PGRs also did not
produce any callus. The average frequency of callus induction for BP
was 78% and the average fresh weight of callus was 10.06 g/explant
after 16 weeks of culture. Best treatment for CI was BP cultured on
4.52 μM 2,4-dichlorophenoxyacetic acid (2,4-D) in combination with
0.45 μM 6-benzyladenine (BA), when they were compared to 2,4-D
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Floral and Nursery Plants Research Unit, USDA, ARS, National Arboretum, Beltsville,
MD, 20705; 2Soybean Genomics and Improvement Laboratory, USDA, ARS, Plant Sciences Institute; 3Floriculture Division, RDA, NHRI, Suweon, Korea; 4Department of Life
Sciences, Ewha Womans University, College of Natural Science, Seoul, Korea
We investigated the interspecific relationships and intraspecific
variations in the genus Corylopsis using RAPD and single nucleotide
polymorphism (SNP) in the internal transcribed spacer1(ITS1), 5.8S
ribosomal RNA gene specific in C. glabrescens Franch. & Sav. Differences in species identification between morphological characteristics
and RAPD result were noticed in some accessions. All C. glabrescens,
C. coreana Uyeki, and C. glabrescens f. gotoana (Makino) T. Yamanaka
accessions clustered in one major group. However, they could be divided
into five subgroups that are not related to the geographical origins. For
example, C. coreana accessions from Korea were clustered with C.
glabrescens from Japan. Although grouping based on SNP data does
not agree with that by RAPD markers, it revealed the limitation in
identification and classification of the genus due to high intraspecific
variations in SNP. At SNP positions 464, 465, 466, 467, and 496, most
accessions of C. glabrescens and C. coreana have C, G, A, A, and T,
respectively. In both analyses, C. glabrescens, C. coreana, and C.
glabrescens f. gotoana Japan are closely related and this suggests that
nomenclature for these three species should be discussed. Although
ITS1 5.8S ribosomal RNA gene can not be used for identification at
a subspecies level of C. glabrescens, it proved to be useful to differentiate C. sinensis from C. sinensis var. calvescens. It is suggested to
use C. glabrescens f. gotoana or C. glabrescens f. coreana rather than
using C. coreana.
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6/20/05 5:01:59 PM
Poster Session 34—Propagation 2
20 July 2005, 12:00–12:45 p.m. Poster Hall–Ballroom E/F
(173) Monolithic Slag as a Substrate for Rooting and
Production of Bare-root Cuttings
Eugene K. Blythe*, Jeff L. Sibley, Ken M. Tilt
Auburn University, Dept. of Horticulture, AL, 36849
Stem cuttings of Hydrangea paniculata Sieb., Rosa L. ‘Red Cascade’,
Salvia leucantha Cav., and Solenostemon scutellarioides (L.) Codd
‘Roseo’ were inserted into six rooting substrates: monolithic slag
[(MgFe)2Al4Si5O18], sand, perlite, vermiculite, Fafard 3B, or fine pine
bark. Rooting, initial shoot growth, and ease of dislodging substrate
particles from root systems upon bare-rooting by shaking and washing
cuttings rooted in monolithic slag were compared to cuttings rooted
in the five other substrates. Rooting percentage, number of primary
roots per rooted cutting, and total root length per rooted cutting for
cuttings rooted in monolithic slag were generally similar to the five
other substrates. Particles of monolithic slag were dislodged more
readily from root systems by shaking than were the other substrates.
Gentle washing removed almost all particles of monolithic slag and
sand from the root systems of all taxa and removed almost all particles
of pine bark from all taxa except S. scutellarioides ‘Roseo’. Monolithic slag had a bulk density similar to sand, retained less water than
the other substrates, and was similar to perlite, vermiculite, and pine
bark in particle size distribution. Our studies indicate that monolithic
slag, where regionally available, could provide a viable material for
producing bare-root cuttings.
(174) In Vitro Regeneration of Cornus kousa
Denita Hadziabdic1, Robert N. Trigiano*1, Stephen Garton2,
Mark T. Windham1
1
University of Tennessee, Entomology and Plant Pathology, Knoxville, TN, 37996-4560;
University of Tennessee, Dept. of Plant Sciences
2
Axillary and apical buds from five Cornus kousa cultivars (‘Little
Beauty’, ‘Samaritan’, ‘Heart Throb’, ‘Rosabella’, and ‘Christian
Prince’) were initially established on two basal media, woody plant
medium (WPM) and woody plant medium/broad leaved tree medium
(BW), amended with the following concentrations of 6–benzylaminopurine (BA): 0, 2, 4, and 8 μM. After explants were transferred at
4-week intervals for 28 weeks beginning in April, only microshoots
of ‘Samaritan’, ‘HeartThrob’ and ‘Rosabella’, were harvested from
proliferating cultures and placed on rooting media. ‘Little Beauty’
and ‘Christian Prince’ did not perform well in multiplication phase of
tissue culture and were excluded from further studies. Rooting media
contained WPM or BW supplemented with either 1-naphthaleneacetic
acid (NAA), indole-3-butyric acid (IBA) or indole-3-acetic acid (IAA)
at the following concentrations: 0, 0.5, 1.5, 4.5, and 13.5 μM. Six weeks
following rooting experiment, preliminary data were collected and
results showed that total of nine plants rooted on both WPM and BW
media supplemented with IBA, 17 plants rooted on media supplemented
with NAA, and 14 plants rooted on media supplemented with IAA.
These results indicated that NAA and IAA appeared to be better for
root production on C. kousa cultivar microshoots than IBA. Additionally, WPM supported more root production, when compared to BW,
even though both media resulted in rooted microshoots. Proliferating
masses were placed on fresh medium with 2μM BA and were used
again for the rooting projects.
(175) In Vitro Regeneration of Cladrastis kentukea
Denita Hadziabdic1, Robert N. Trigiano*1, Stephen Garton2,
Mark T. Windham1, William E. Klingeman2
1
University of Tennessee, Entomology and Plant Pathology, Knoxville, TN, 37996-4560;
University of Tennessee, Dept. of Plant Sciences, Knoxville, TN, 37996-4561
2
Axillary buds from a single Cladrastis kentukea tree were initially
cultured on two media, woody plant medium (WPM) and Murashige
and Skoog (MS) containing 0, 1, 2, or 4 μM 6–benzylaminopurine (BA).
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Cultures were transferred to fresh media every 4 weeks. Elongated
shoots were harvested after 39 weeks and transferred to half-strength
MS medium supplemented with the following concentrations of IBA:
0, 3, 30, 100, and 300 μM for 3 d, then returned to half-strength MS
without growth regulators. Explants exposed to 300 μM of IBA produced significantly more roots (75%) compared to explants exposed
to other treatments. Fifty-four and 45% of the microshoots rooted
when exposed to 100 and 30 μM IBA, respectively. Only 4% of the
microshoots rooted when exposed to 3 μM IBA and none of the control
microshoots rooted. Although the 300 μM treatment yielded the most
rooted plantlets, there was significantly higher terminal meristem
abortion compared to other treatments. There were no statistical differences between the numbers of roots and total root length among
all treatments. Additionally, all microshoots that rooted had lenticels,
suggesting that presence of lenticel cambial activity can possibly improve rooting abilities of selected microshoots. Rooted microshoots
were gradually acclimatized to nonsterile environment.
(176) In Vitro Germination of Galax under Different
Culture Medium pH Conditions
Guochen Yang*, Carl Niedziela, Zhongge (Cindy) Lu
North Carolina A&T State University, Natural Resources and Environmental Design,
Greensboro, NC, 27411
The goal of this study was to expedite galax seed germination in vitro.
Galax seeds were collected from Yancey County, N.C., at an elevation
of about 1100 m. Aseptic cultures were established using the tiny rustcolored seeds. In vitro seed germination was achieved under different
pH conditions (4.2, 5.0, and 5.8). Seeds cultured in the medium with
pH 4.2 tended to germinate early with a better rate than those cultured
with a higher pH of 5.0 or 5.8 at the very beginning. Gradually, seeds
from media with pH 5.0 and 5.8 caught up in germination. Eventually,
seeds from all pH treatments produced a very similar germination
rate. Attempts to use the matted and scaly rhizomes and very tender
new growth as explant materials to establish aseptic cultures were not
successful, due to severe contamination. However, our observations
suggested that the very tender new growth could be a good source of
explants once the optimum sterilization time is established.
(177) Evaluation of Different Factors on Regeneration of
Plantlets from Embryos of Cycas revoluta Thunb.
Laura M.R. Rinaldi*
CNR, IVALSA, Via Madonna Del Piano, Sesto Fiorentino, Firenze, 50019, Italy
The micropropagation of Cycas revoluta Thunb. via somatic embryogenesis was tested on immature and mature embryos using 2,4dichlorophenoxyacetic acid (2,4-D) in combination with benzyladenine
(BA) or kinetin. In addition, the effect of media manipulation on
the induction of adventitious buds was studied to optimize culture
parameters for the regeneration of plantlets via organogenesis from
mature embryos. Schenk and Hildebrandt basal medium containing
six different NO3- : NH4+ ratios (from 90:10 to 65:35) and BA at 9 μM
was used. The development of induced buds occurred on the medium
containing the identical NO3- : NH4+ composition without growth
regulators. The effects of two IBA concentrations on the rooting of
elongated shoots were evaluated. The treatment of immature embryos
with 2.26 μM 2,4-D and 0.44 μM BA and that of mature embryos with
0.9 μM 2,4-D and 4.40 μM BA promoted growth of embryogenic
tissue followed by embryo formation that failed to develop further.
Bud induction was obtained through the whole range of NO3- : NH4+
ratios tested. Small decrease in these ratios affected subsequent differentiation and growth. Adventitious shoots obtained on 70% NO3showed two-fold increase in height and diameter compared with those
regenerated on 75% NO3-. Furthermore, 7% of the former produced
at the shoot base adventitious shoots that have similar morphology
to offset growing at the base of mature plant. The rooting percentage
of shoots was low. Considering the difficulty in achieving somatic
embryogenesis, these results suggested that among micropropagation
techniques organogenesis can be applicable for production of Cycas,
although rooting is still the limiting factor.
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6/20/05 5:02:00 PM
(178) Layering Propagation of Bigtooth Maple, Acer
grandidentatum
(196) Inducing Lettuce Tipburn with Relative Humidity
Modification
Larry A. Rupp*1, William A. Varga2, Roger Kjelgren3
H. Chris Wien*1, David S. de Villiers2
1
1
Utah State University, Plants, Soils, and Biometeorology, Logan, UT, 84322-4820;
Utah State University, Utah Botanical Center; 3Utah State University, Plants, Soils, and
Biometeorology
2
Tipburn is a necrosis of the rapidly expanding young leaves of lettuce,
caused by a localized Ca deficiency that is a major constraint to raising
productivity of hydroponically-grown leaf lettuce. Root pressure is
thought to be important in distributing calcium to young tissue that is
not transpiring rapidly in crops such as cabbage, tomato and strawberry.
Since root pressure is enhanced by high relative humidity (RH), experiments were conducted with two cultivars of leaf lettuce to determine
if regulating relative humidity during the day or night would influence
tipburn incidence. Lettuce was grown hydroponically in a glass-covered
greenhouse. Plants were transferred to ponds of 1 × 2 m size, starting
at about day 25 from sowing. Four ponds containing 42 plants each
were subjected to ambient or elevated RH, either during the day, or at
night, or at both times. Each pond was covered by a clear polyethylene
ventilated canopy, to ensure maintenance of the desired RH condition.
The experiment was conducted five times. In three experiments, tipburn
developed in 3 or 7 days, depending on the cultivar. The disorder was
most severe in ponds whose atmosphere was constantly humid, followed
by the treatment that provided humid days and dry nights. Treatments
which provided dry conditions, either during the day, or continuously,
were least affected. In two experiments, ambient RH rose above 70%,
and the differential effect of humidity on tipburn incidence was no
longer evident. Both cultivars reacted similarly to the treatments, even
though ‘Winter Density’ developed the disorder 4 days before ‘Batavian’.
The results imply that root pressure is less important than transpiration in distributing Ca to the edges of young leaves of leaf lettuce.
(197) Effect of the Number of Fruit per Plant on
Production of Dried Seed and Fruit Yield in Pumpkin
Poster Session 35—Vegetable Crops Management–
Cropping Systems 2
20 July 2005, 12:00–12:45 p.m. Poster Hall–Ballroom E/F
(195) Evaluation of Solid Artificial Media on Lettuce
Seedling Growth and Anchorage
Jill A. Montgomery*, H. Chris Wien
Cornell University, Horticulture, Ithaca, NY, 14850
A study was conducted to compare three sterile, commonly used soilless media (Agrifoam™ and Oasis™, growth foams, and Grodan™, an
expanded rockwool substrate) to determine which media characteristics
favor seedling development and establishment in hydroponic systems.
These media were studied during days 7–10 of the seed germination
stage, when one often observes with the use of foam media the occurrence of “pop-outs,” a disorder in which actively growing roots
do not penetrate and spiral on the media surface causing the root tip
to die. High percentages of pop-outs cause poor seedling stand, and
discourage the use of soilless media for seedling germination. Pop-outs
were more frequently observed in Agrifoam (50%) compared to the
other media, with Oasis intermediate (15%), and Grodan least affected
(>5%). Both physical and chemical characteristics were analyzed to
isolate the causes of pop-outs. Oasis and Agrifoam both have higher
water retention, and pop-outs increased as the water content of the
foam increased. High soluble salts, particularly high magnesium in
the root zone, produced roots that were “burned” and did not grow.
When magnesium salts in concentrations equivalent to that found in
Agrifoam were added to Grodan (control substrate), the number of
pop-outs increased. The roots were stunted with little or no root hairs,
resembling roots when grown in Agrifoam. We conclude that the high
incident of pop-outs in Agrifoam, and to a lesser extent, in Oasis, is
caused by high-medium water content and toxic levels of magnesium
ions in solution.
Sang Gyu Lee*1, Dong Kum Park1, Kyung Sup Park1,
Yun Chan Heo1, Yoon Ah Jang1, Kwan Dal Ko1, Chiwon W. Lee2
1
National Horticultural Research Institute, Vegetable Research Division, 475 Imok-dong,
Jangan-gu, Suwon, Kyunggi-do, 440-706, South Korea; 2NDSU, Plant Sciences, 266F
Loftgard Hall, Fargo, ND, 58105-5051
The fruits of pumpkin are good material for soup and a very popular
side dish in Korea. The purpose of this study was to investigate how
number of fruit set per plant (2, 3, or 4 fruit) affected production of
dried seed and fruit yield. ‘Golden Delicious’ (GD) and hull-less (HL)
pumpkins were planted 60 cm apart in 200-cm rows. Production of
dried seed per hectare (11,000 plants) were 1985, 2193, and 2074 kg,
respectively, at 2-, 3-, and 4-fruit set per plant for GD. The fruit yield
per hectare (11,000 plants) was 58,360 kg for 2-fruit set treatment,
74,680 kg for 3-fruit set, and 73,240 kg for 4-fruit set per plant for GD.
The production of dried seed per hectare (11,000 plants) was 535, 603,
and 545 kg, respectively, for 2-, 3-, and 4-fruit set per plant for HL.
The fruit yield per hectare (11,000 plants) was 28,200 kg for 2-fruit
set treatment, 44,660 kg for 3-fruit set, and 39,200 kg for 4-fruit set
per plant for HL. The highest production of dried seed and fruit yield
were for 3-fruit set per plant for GD and HL. Differences in production
for dried seed and fruit yield, as influenced by number of fruit set per
plant, were also characterized.
POSTERS–WEDNESDAY
Bigtooth maple (Acer grandidentatum Nutt.) is of interest for its fall
color and potential use in water-conserving landscapes. Clonal propagation of desirable selections would be beneficial. Since bigtooth maple
commonly self-propagates by layering, we explored mound layering
as a means of vegetative propagation. A stool bed was established in
1999 with seedlings grown from northern Utah seed. Beginning in
2001, seedlings were dormant pruned to their base and shoots allowed
to grow until early July, when treatments were applied. At the time of
treatment application for the reported experiments, shoot bases were
girdled with 24-gauge copper wire, covered with conifer wood shavings, and kept moist during the growing season. The effects of rooting
hormones and enclosure of the rooting environment on rooting were
examined. On 7 July 2002, 32 trees were randomly selected and the
four tallest shoots within each tree were treated with either 0, 1:5, 1:10,
or 1:20 (v/v) solutions of Dip-N-Gro© rooting hormone (1% IBA, 0.5%
NAA, boron). There was no significant difference in rooted shoots
between treatments and 81% of the trees had at least one rooted shoot.
On 9 July 2004, 39 trees were selected and two shoots per tree were
girdled. One-half of the stool bed area was treated by underlaying the
shavings with BioBarrier© (17.5% trifluralin a.i.). Measurements on 12
Nov. 2004 showed no apparent treatment effect on rooting and 90%
of the trees had at least one rooted shoot. This research demonstrates
that mound layering is an effective means of rooting shoots of juvenile
bigtooth maples. Further research will examine the effectiveness of
the technique in propagating mature clones.
Cornell University, Horticulture, 156 Plant Science Hall, Ithaca, NY, 14853; 2Cornell
University, Biological and Environmental Engineering, Ken Post Laboratory
(198) Growth and Development of Watermelon Plants
Grafted onto Citrullus Rootstocks Selected for Disease
Resistance at Two Temperature Regimes
Yun-Chan Huh1, Du-Hyun Kim2, Sang-Gyu Lee1,
Kyoung-Sub Park1, Dong-Kum Park1, Young-Hoe Woo3,
Jung-Myung Lee*4
1
National Horticultural Research Institute, Vegetable Science Division, 475, Imok-dong,
Jangan-Gu, 441-440, Korea, Suwon, Gyeonggi-do, 440-706, Korea; 2National Plant Quarantine Service, Pest Survey & Control Division, 433-1 Anyang 6-dong, Manan-ku, Anyang,
Gyeonggi-do, 430-016, Korea;3Korea National Agricultural College, Dept. of Vegetable, 11-1
Donghwa-Ri Bongdam-eup, Hwaseong, Gyeonggi-do, 445-893, Korea; 4Kyunghee University, Dept. of Horticulture, 1 Sochen-ri, Giheung-eup, Yongin, Gyeonggi-do, 449-701, Korea
Growth response of ‘Sambok Honey’ watermelon grafted onto different
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rootstocks, including four Citrullus rootstocks and three other cucurbitaceous rootstocks, was evaluated at low and normal temperature
regimes. Marked reduction in plant growth rate was observed in plants
grown at low temperatures as compared to those grown at normal or
optimal temperatures. Relative growth reduction rates were 40% to
48% for vine length, 39% to 51% for total leaf area, 37% to 60% for
shoot fresh weight, and 50% to 79% for shoot dry weight, respectively. Watermelon rootstock PI 482322 showed comparable plant
growth as the most popular rootstock (Shintozwa pumpkin) even at
low temperatures. ‘Sambok Honey’ watermelon grafted onto watermelon hybrids ‘PI 271969 × PI 296341’ and ‘PI 271769 × Calhoun
Gray’, showed comparable plant growth as FR Dantos bottle gourd
rootstock. Index of growth ability at low temperature (IGALT), which
was calculated on the basis of reduced rate of vine length, dry weight,
and leaf area, was comparatively high in C. martinezii, Shintozwa,
PI 482322, and ‘PI 271769 × PI 296341’ rootstocks (50% or higher)
and lowest in own-rooted ‘Sambok Honey’ or in watermelon plants
on ‘Knight’ rootstock. Watermelon hybrids ‘PI 271969 × PI 296341’
and ‘PI 271769 × Calhoun Gray’ exhibited better or at least comparable growth at low temperatures as compared to ‘FR Dantos’, thus
confirming the feasibility of using watermelon rootstocks even in
winter greenhouse conditions.
(199) Effect of Soil Amendments and Mulching on the
Incidence of Fusarium Wilt and Cantaloupe Yield in the
Pacific Central Region of Mexico
Mario Orozco-Santos1, Javier Farías-Larios*2, Jaime MolinaOchoa2, José Gerardo López-Aguirre2
1
INIFAP, Campo Experimental Tecomán, Colima, 28100, México; 2Universidad de Colima,
Facultad de Ciencias Biológicas y Agropecuarias, Tecomán, Colima, 28100, México
Melon wilt (MW) is one of the main diseases affecting the cucurbitaceous crops in the Pacific Central region of Mexico. The use of resistant
varieties is the most effective strategy to reduce the damage caused
by MW; however, variety performance depends on the fungal race
occurring in the field. The use of fungicides, such as benzimidazols
and methyl bromide, is a common practice, but there are contamination
concerns, and a search is on for alternatives to diminish the negative
effects on the agro-ecosystem. The aim was to determine the effect
of the application of soil amendments and mulching on the incidence
of MW, and on melon yield. Soil amendments incorporated were:
rice straw (3 t·ha-1); compost 1, prepared with chicken and bovine
manure, and banana and orange wastes (5.7 t·ha-1); compost 2, prepared with bovine and horse manure, coconut wastes and grasses (8
t·ha-1), vermicompost (3 t·ha-1), and a control. All treatments were
established using transparent mulching during 21 days. The number
of MW propagules in amended soils were similar at 5, 10, and 20
cm deep, but the percentage of diseased plants was higher (4.5%) in
the control, which could be caused by the incidence of other fungi
propagules, perhaps antagonistic, that contributed in diminishing the
MW when compared with the control. The fruit weights and fruit
sizes were not different between treatments on small (21–30 sizes),
medium (15–18 sizes), and large (9–12 sizes), but total fruit numbers
were 1.15-, 1.07-, 0.99-, and 1.09-fold higher when compared with the
control. The application of soil amendments affected the antagonistic
fungal populations even when it did not affect the cantaloupe yield. We
suggest that soil amendments will improve soil fertility and increase
melon yields, and studies are currently running.
(200) Influence of Planting Density on Yield and Quality
of Confectionery Seed Pumpkins
Sung Eun Lee*, Chun Ho Pak, Yong Beom Lee, Harlene Hatterman-Valenti, Chiwon W. Lee
North Dakota State University, Plant Sciences, Loftsgard Hall, Fargo, ND, 58105
A field study evaluated the influence of planting density on the yield
and quality of confectionery seed pumpkins grown near Hatton, N.D.
An open-pollinated selection of Chinese snow-white seeds (CS) and
a hull-less (HL) seed cultivar (‘Takai’, Johnny’s Selected Seeds)
were grown at three different planting densities (1-, 2-, or 3-ft plant
spacing on rows 5 ft apart) from 5 May to 7 Oct. The total number of
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plants at high, medium, and low densities was 8712, 4356, and 2904
per acre (21,529, 10,764, and 7176 plants per ha, respectively). The
average number of fruits harvested at high, medium, and low densities,
respectively, was 0.93, 1.2, and 1.4 per plant for CS and 1.2, 1.7, and
2.5 per plant for HL. Total seed yields were estimated at 1011, 599,
and 466 kg/acre (2498, 1480, and 1151 kg·ha-1) for CS and 661, 500,
and 498 kg/acre (1633, 1235, and 1231 kg·ha-1) for HL, respectively,
at high, medium, and low planting densities. While the average weight
of fruits decreased as planting density increased, the total number and
weight of seeds produced per fruit were unaffected by changing plant
density in either cultivar.
(201) Strategies to Encourage Grower/Industry
Participation in the Development of BMPs for Vegetables
in Southern Florida
Mary Lamberts*1, Teresa Olczyk2, Phyllis Gilreath3, Gene McAvoy4, Alicia Whidden5, Darrin Parmenter6, Ed Skvarch7, Yuncong
Li8, Christine Coffin9, Donald Pybas1
1
University of Florida, Miami-Dade County Extension, Homestead, FL, 33030-2309;
University of Florida, Miami-Dade County Extension, Homestead, FL, 33030-2309;
University of Florida, Manatee County Extension, 1 Palmetto, FL, 34221; 4University
of Florida, Hendry County Extension, LaBelle, FL, 33975; 5University of Florida, Hillsborough County Extension, Seffner, FL, 33584; 6University of Florida, Palm Beach
County Extension, West Palm Beach, FL, 33415; 7University of Florida, St. Lucie County
Extension, Ft. Pierce, FL, 34945; 8University of Florida, Tropical Research & Education Center, Homestead, FL, 33031; 9USDA, Natural Resource Conservation Service,
Florida City, FL, 33034
2
3
Florida, like other states, is developing BMPs for specific commodities. Vegetables are in a statewide document that includes field crops.
Vegetable advisory committee members from the counties in southern
Florida were concerned that the existing document was too broad in its
scope and that many practices did not apply to production on sandy or
calcareous soils. Based on grower comments, extension agents organized grower meetings to address these issues. The first meeting was a
presentation by the Florida Department of Agriculture and Consumer
Services (FDACS) Office of Agricultural Water Policy. The second
meeting in Miami–Dade was a hands-on session, where growers and
industry were divided into three areas—nutrition, pesticides, and water
quality. Each group was facilitated by a faculty member or the NRCS
conservationist. Other counties used newsletters and other methods to
receive grower feedback. Participant comments were compiled and
forwarded to FDACS, where they are being incorporated into a greatly
revised document. Concerns will be presented.
(202) Microclimate and Reference Crop
Evapotranspiration in High Tunnels and Open Field
during Summer Lettuce Production
Xin Zhao*1, Edward E. Carey2
1
Kansas State University, Horticulture, Forestry and Recreation Resources, Manhattan,
KS, 66506; 2Kansas State University, Horticulture, Forestry and Recreation Resources,
Olathe, KS, 66061
High tunnels, unheated greenhouses, have been shown to be a profitable season-extending production tool for many horticultural crops.
Production of cool-season vegetables during hot summer months can be
achieved using shaded high tunnels. Microclimate in high tunnels and
open field was monitored during summer trials of leaf lettuce, in which
unshaded tunnels and shaded tunnels (39% PAK white shadecloth)
were used, respectively, in 2002 and 2003. Wind speed was consistently
lower in high tunnels. Compared to open field, daily air temperature
was about 0.7 °C higher in unshaded high tunnels, and 0.5 °C lower in
shaded high tunnels. Relative humidity was slightly lower in unshaded
tunnels, but tended to increase in shaded tunnels, in comparison to
the open field. When using shadecloth, soil temperature was lowered
by 1~3 °C and the leaf surface temperature was significantly reduced
by 1.5~2.5 °C. In shaded high tunnels, PAR light dropped by at least
50% relative to the outside, where the maximum PAR light intensity
reached 1800 μmol·m-2·s-1. Overall, shaded high tunnels resulted in
higher quality lettuce, with less bolting and bitterness. Reference crop
evapotranspiration (ET0) was estimated from meteorological data on
a daily basis using the FAO-56 method. ET0 was lowest in shaded
high tunnels, and highest in the open field. Relatively lower ET0 in
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high tunnels indicated a likely lower water requirement and therefore
improved water use efficiency compared with the open field.
(205) Root Restriction Improves Nutritional Values of
Hydroponically Cultured Leafy Vegetables
(203) Evaluation of Phostrol for Downy Mildew Control
on Pumpkin (C. pepo)
Tae-Cheol Seo*1, Changhoo Chun2, Hyung-Kweon Yun1,
Han-Cheol Rhee
Winfred Cowgill1, Kristian Holmstrom2, Andrew J. Wyendandt3,
Jon Clements4, Martha Maletta*1
1
Rutgers and the N.J. Ag. Experiment Station, Rutgers Cooperative Research of Hunterdon County Extension, Flemington, NJ, 08822; 2Rutgers and the N.J. Ag. Experiment
Station, Rutgers Cooperative Research and Extension, 9Cook College, New Brunswick,
NJ, 08901-8524; 3Rutgers and the N.J. Ag. Experiment Station, Rutgers Cooperative
Research and Extension, Bridgeton, NJ, 08302-5919; 4University of Massachusetts, U
Mass Extension, Horticultural Research Center, Belchertown, MA, 01007
(204) The Effect of High Tunnels and Row Covers on
Air Temperatures and Spring-planted Tomato Yield in
Louisiana
Koji Takeuchi*, Carl E. Motsenbocker
Louisiana State Univ., Agriculture Center, Dept. of Horticulture, Baton Rouge, LA, 70808
Tomato is an important vegetable crop in Louisiana for small- to largescale growers. Growers often use protected cultivation with structures,
such as greenhouses, in order to take advantage of higher prices early
in the season and increase profits through increased tomato yield and
quality. A negative aspect of greenhouse use is the high investment
and production costs associated with these structures. High tunnels,
or simple greenhouse-like structures, have been used to protect crops
from cold temperature in northern states, as they often provide benefits
similar to greenhouses with considerably lower cost. Very little research
has been conducted on the use of high tunnels for crops in the southern
states. High tunnels in combination with row covers were evaluated
for field cultivation of spring season fresh market tomato in Louisiana. The studies were set up in a randomized complete-block design
with three replications. Tomatoes were transplanted into single rows
on four-row raised beds covered with black plastic mulch on 1.2-m
centers on 13 Mar. 2004. Row covers were installed immediately after
transplanting and removed on 3 May. Plants were harvested for 6 weeks
starting 12 May 2004. Both high tunnels and row covers significantly
increased minimum and maximum air temperatures at a 15-cm height
compared to the black plastic mulch control. Early yield was highest
with the tunnel treatment without row cover compared to tunnel with
row cover and similar to row cover alone or the control. There were
no differences in total marketable yield between treatments. Research
results from 2 years will be presented.
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Edible chrysanthemum, pak-choi, endive, chicory, and lettuce were
hydroponically cultured under root-restricted conditions in DFT systems
and their growth and nutritional values were investigated. Cylindrical
plastic tubes 100 mm tall and 20, 25, and 30 mm in diameter were
used for root restriction. Growth of all the species was retarded, as
the roots were restricted. Pak-choi and edible chrysanthemum showed
the greater reduction in growth compared with chicory and endive.
Percentage of dry matter, C:N ratio, and ascorbic acid and anthocyanin
contents increased in the root-restricted treatments. Changes in mineral
contents as affected by root restriction were not consistent among tested
species. Optimized root volumes to improve the nutritional values and
to reduce the retarding of growth varied according to species of leafy
vegetables. Tubes of Φ25mm × 10cm and Φ30mm × 10 cm gave the
best results in chicory, endive, and lettuce, and edible chrysanthemum
and pak-choi, respectively. Results indicate that nutritional values of
hydroponically cultured leafy vegetables can be improved by root
restriction using plastic tubes.
(206) Control Methods for Mexican Bean Beetle
(Epilachna varivestis Mulsant) Infestations on Snap Bean
(Phaseolus vulgaris L.) Crops
Tiffany Fess*, Sven Verlinden
West Virginia University, Division of Plant and Soil Sciences, Morgantown, WV,
26506
Three different control methods, row cover, staggered plantings,
and the release of a parasitic wasp, Pediobius foveolatus, were used
to test effectiveness at controlling Mexican bean beetle (MBB)
infestations on snap beans. The study consisted of six plots, on five
different farms in the Morgantown, W.Va. area, three with and three
without the application of the control methods. Releases of 15 adults
and 100 larvae during flowering of the bean crop occurred at each
plot. Weekly counts of the three MBB life stages, parasitized MBB
larvae, and bean yields were taken. The results showed that the release of the parasitic wasp maintained the MBB populations below
economic thresholds throughout the growing season. The average yield
from plots that received wasp treatments was 34.2 kg, compared to
15.2 kg harvested from untreated plots. Plots that received row cover
treatments were shown to be slightly more effective than staggered
plantings at controlling MBB populations. Row cover plots yielded an
average of 15.3 kg, in comparison to the 11.8 kg yield from untreated
plots, while staggered plantings in treated plots yielded 9.5 kg, compared to 6.0 kg from untreated plots. End of season MBB populations
in treated plots consisted of 75 adults, 57 pupae, 275 larvae, and 94
parasitized larvae compared to untreated populations, 98 adults, 214
pupae, 420 larvae on average. In conclusion, increased yields can likely
be correlated to decreased MBB populations, indicating the release
of P. foveolatus as a viable option for control of MBB, especially in
organic systems.
POSTERS–WEDNESDAY
Downy mildew (DM) is a serious foliar fungal disease of cucurbits.
DM can cause yield losses for New Jersey growers if not properly
controlled. In 2004, five chemical control programs were evaluated in
a research trial at the Rutgers Snyder Research and Extension Farm
(Hunterdon Co.). Materials evaluated were: 1) Phostrol, 5 pt/A; 2)
Phostrol, 5 pt/A plus Bravo WS, 3 pt/A; 3) Flint WDG, 2 oz/A alternated with Bravo WS, 3 pt/A plus Nova 40W, 5 oz/A; 4) Maneb 75DF,
2 lb/A plus Champ Formula 2 Flowable, 1 1/3 pt/A; and 5) untreated
control. All fungicide programs were applied weekly. Phostrol (Nufarm
Americas, Inc.) is a new product with systemic mode of action that is
newly labeled for cucurbits for control of DM, but not powdery mildew
(PM). The active ingredients are mono- and dibasic-sodium, potassium,
and ammonium phosphates. Phostrol and Phostrol plus Bravo were
evaluated against industry standard fungicide programs which include
alternating chlorothalonil + myclobutanil with strobiluron chemistries
on a weekly basis. Fungicide applications were made weekly beginning at first observance of DM in the field on 23 July. Plots were
rated for DM and PM incidence and extent of defoliation on 6 Aug.
and 24 Sept. Phostrol plus Bravo applied on a weekly basis (7 to 10
days) provided the best control of DM, which appeared much earlier
in the season than usual in northern New Jersey. Treatments Phostrol,
Flint alternated with Bravo + Nova, Maneb + Champ reduced DM
compared to the UTC. Maneb plus Champ provided the best control
for PM. At harvest, fruit was graded and weighed. Marketable yield
from Phostrol, Phostrol plus Bravo and Maneb plus Champ treatments
was significantly higher than the UTC and Flint/Bravo plus Nova
treatment. Handle quality was not affected by treatment.
1
National Horticultural Research Institute, Vegetable, I-mok Dong 475, Jang-an Gu,
Suwon, Gyeonggi, 440-706, South Korea; 2Seoul National University, Plant Science,
San 56-1, Sillim-dong, Gwanak-gu, Seoul, 151-742, South Korea
(207) Productivity and Fruit Quality in European
Cucumber under Greenhouse Conditions in Northwest
Mexico
Raul Leonel Grijalva-Contreras*1, Rubén Macias-Duarte1,
Fabián Robles-Contreras1, Manuel de Jesus Valenzuela-Ruiz1
1
INIFAP-Caborca, Protected Horticulture, Caborca, Sonora, 83600, México; 2INIFAPCaborca, Soli & Horticultural; 3INIFAP-Caborca, Agroclimatology; 4INIFAP-Caborca,
Viticulture
Mexican production of vegetables under greenhouse conditions has
been increased notably during the last year to about 1500 ha. The main
crop in greenhouse production is tomato, but european cucumber is a
potential crop due to high yield and quality, with a good price in the
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marketplace and a short growing season. The objective of this trial was
to evaluate eight european cucumber varieties and to choose those with
high yield and fruit quality, and disease resistance. The experiment was
carried out at the experimental station (INIFAP-CIRNO). Greenhouse
conditions were: polyethylene (8.0 mL), without temperature control;
natural ventilation; and soil with electrical conductivity of 1.22 dS·m-1
and pH 7.96. Sowing date for seed was 15 Oct. 2004. Plant density
was 3.78 plants per m2. The harvest period was 26 Dec. 2004 to 11
Mar. 2005, with an average of 10 cuttings. Varieties with highest yield
were ‘Imanaol’, ‘Bermejo’, ‘Dominica’, and ‘Kalunga’, with 18.9,
15.2, 14.8, and 14.3 kg·m2, respectively. Fruit quality was excellent
in all varieties; however, ‘Imanaol’ had the highest percentage of size
and fruit number. The main insect pest during the year was white fly
(Bemissia sp.) and the most important disease was powdery mildew
(Erishipe cichoracearum).
Poster Session 36—Vegetable Crop Physiology
20 July 2005, 1:15–2:00 p.m.,
Poster Hall–Ballroom E/F
(208) Production of Double-stemmed Grafted Tomato
Plug Seedlings
Ki-yun Jung*, Yu-Jin Park, Jung-Myung Lee
Kyung-hee Univ., Horticulture, Sdochon-Ri 1, Kiheung-up, Yongin-si, Gyunggi, 449701,
Korea
Cultivation of grafted tomatoes has been sharply increased in recent
years. Millions of grafted seedlings were grown in California as well
as other parts of the world, and the need for high quality grafted tomato
seedlings is also rapidly growing. Since the price of grafted plug seedlings are 3–4 times higher than the nongrafted ones, production and
commercial distribution of double-stemmed plugs, even though slightly
more expensive than the single-stemmed plugs, will greatly cut down
the expenses needed to purchase grafted seedlings. Several methods of
producing double-stemmed grafted plug seedlings are presented and
the advantages as well as the disadvantages of these methods will be
fully discussed. Brushing or painting lanolin paste containing thidiazuron at 100–500 ppm to the lower node of the decapitated scion is
effective in fast-growing cherry, whereas inducing double stems from
the cotyledonary node of grafted scions appeared to be more practical
for ordinary tomatoes for table use. Methods of grafting, especially in
relation with machine grafting, will be discussed.
(209) Rooting Response of Grafted Seedlings of Hot
Peppers (Capsicum annuum)
Hee-Ju Lee*1, Sang-Gyu Lee2, Jung-Myung Lee3
1
Rural Development Administration, Farm Management and Information Bureau, 250
Seodun-Dong, Suwon, Gyeonggi-Do, 441707, Korea; 2NHRI, Vegetable Division;
Kyung-Hee Univ., Horticulture
3
Increasing numbers of vegetables are being grafted in recent years and
many different grafting methods, as well as grafting aids, have been
developed and practiced among farmers as well as commercial plug
seedling producers. For solanaceous crops, such as tomatoes, peppers,
and eggplants, splice grafting at very young stages of development is
recommended. Several types of grafting machines and/or robots are
now available for commercial use. The presence of roots often slows
down and reduces the efficiency of robot or machine grafting. Therefore,
grafting with root-removed rootstocks is frequently used for grafting,
mostly because of the grafting efficiency, especially in cucurbitaceous
crops. The feasibility of producing grafted pepper plug seedlings using
root-removed rootstock was investigated. After grafting, the seedlings
were placed in pot soil in cell trays, usually 128-cell trays, and then
placed in a conditioning room for subsequent rooting and graft union
formation. Young pepper cuttings readily rooted in pot soils and the
use of rooting substances greatly accelerated the speed of rooting.
Even though rooting was delayed a few days in grafted seedlings,
normal rooting took place in all graft combinations.
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(210) Effect of Shading on the Germination and
Vegetative Development of ‘Jalapeño’ Hot Pepper
(Capsicum annuum L.)
Marcelino Bazan Tene*, Juan Manuel González Gonzalez,
Francisco Radillo Juarez, Jorge Pahul Covarrubias Corner,
Salvador Guzman Gonzalez
Universidad de Colima, Facultad de Ciencias Biológicas y Agropecuarias, Tecomán,
Colima, 28100, México
The hot pepper (Capsicum annuum L.) is a plant domesticated
in Mesoamerica. Hot pepper is currently widespread worldwide, and
its uses are varied, such as for flavoring, pigment base, and as a nutritional food resource. Mexico produces about 623,238 tons/year of
fresh fruits in 136,398 ha; the State of Colima produced 17,181 tons
in 676 ha, with a mean of 27 t·ha-1. The culture of hot pepper in Colima faces certain limitations to its productive potential, such as lack
of fertile and well-drained soils, constant soil moisture, and being
free of weeds during the first weeks after transplanting; and maintaining plant uniformity in transplantation. This last practice is carried
out in the side bed, but there is a lack of scientific evidence about the
requirements of luminosity in the seed nursery in order to accelerate
improvement of plant quality for transplanting, and the impact on
fruit yield. The aim of this study was to evaluate the effect of different levels of shading on germination and vegetative development of
‘Jalapeño’ hot pepper under greenhouse conditions. Four levels of
luminosity were evaluated using mesh fabrics in order to produce 90%,
75%, and 50% shade, and control (0%) without shading on the seed
beds. A completely randomized design with four treatments and four
replications was used. The shading treatments reduced the germination
period in about 2 days; increased the percentage of germination with
a range between 1.6% and 3.7%; increased the plant height 2.3, 4.8,
7.72, and 10.1 cm at 3, 7, 13, and 18 days postemergence; increased
the root biomass about 7.1 g/plant, and 5.4 g of fresh foliage with the
90% shade treatment in comparison with control. Overall, a better
agronomic performance of the ‘Jalapeño’ hot pepper was obtained
with 90% shading.
(211) Effect of Supplementary Light on Growth and
Physiological Characteristics of Cucumber (Cucumis
Sativus L.) Seedlings in the Greenhouse
Yuhe Li, Feishi Luan*, Hongyan Ma
Northeast Agricultural University, Horticultural College, Xiangfang District, Harbin,
Heilongjiang, 150030, China
This experiment researched the effects of supplementary light
on cucumber [Cucumis sativus (L.)] seedling growth and some physiological characteristics under the same temperature. The purpose was
to afford basic light condition control of cucumber cultivation in
a greenhouse during winter to spring. Two cucumber cultivars,
No. 3 ‘Jinchun’ (greenhouse cultivar) and No. 7 ‘Longzahuang’ (open
field cultivar), were transplanted with supplementary light at different
intensities. The experimental results indicate that plant height, leaf area,
and stem diameter of cucumber seedlings were significantly increased
with increasing intensity of supplementary light. Supplementary
light at the cucumber seedling stage led to the increase of chlorophyll
content, soluble sugar content, protein content, and CAT activity.
At the same time, reduction in POD activity and MDA content
with increasing levels of supplementary light was found. In addition, cells of supplementary light treatments have more chloroplasts,
grana, and starch grains. Chloroplast growth of supplementary
light treatments was better than CK. The grana lamella was arranged in order and its structure was clear. These results show that
supplementary light could improve the growth of seedling plants,
alleviate the damage of membrane lipid peroxidation, and facilitate
chloroplast growth. The effects of supplementary light on the
two cultivars were the same, but their extent was different. Effects
on No. 7 Longzahuang were more significant than those on No. 3
Jinchun.
HORTSCIENCE, VOL. 40(4), JULY 2005
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(212) Gas Exchange and Antioxidant Properties of Two
Spinach (Spinacia oleracea L.) Cultivars of Contrasting
Morphology
Alexis M. Barbarin1, Frank J. Williams*1, Greg T. Bettmann2,
Donald P. Hauber3, Harish H. Ratnayaka1
1
Xavier University of Louisiana, Department of Biology, New Orleans, LA, 70125; 2New
Mexico State University, Department of Entomology, Plant Pathology and Weed Science;
3
Loyola University of New Orleans, Department of Biology
`
(213) Effect of Shading on Yield and Composition of Fruit
and Leaves of Greenhouse Tomato
Martin P.N. Gent*
Poster Session 37—Small Fruit
20 July 2005, 1:15–2:00 p.m.
Poster Hall–Ballroom E/F
(366) Bloom Delay and Fruit Thinning of Blueberry with
Soybean Oil
Dennis Deyton*1, Carl E. Sams1, Jim R. Ballington2,
John Cummins1
1
University of Tennessee, Department of Plant Sciences, Knoxville, TN, 37796-4561;
N.C. State University, Horticulture Department, Raleigh, NC, 7695-7609
2
Tomatoes were grown in spring and summer in Connecticut in greenhouses covered with a double layer of 4-mL clear polyethylene film.
Some sections were covered with reflective aluminized shadecloth
that provided 85%, 70%, or 50% transmittance of direct radiation,
respectively. This shading was applied in mid-June, after fruit began
to ripen, and remained for the rest of the summer. Fruit was picked
through August. A similar experimental protocol was used in 2003 and
2004. The maximum shading only decreased daily integrated solar
radiation to 69% of that without shade, as measured by PAR sensors set
at a 2-m height in each greenhouse. Shading reduced yield of ripe fruit
from 16.6 and 13.1 kg·m-2, proportional to the measured decrease in
radiation. Neither fruit size nor weight fraction of marketable fruit was
affected by shading in 2004. Nutrient content was analyzed in tissues of
ripe fruits, and uppermost expanded leaves harvested in early August.
As shading decreased transmittance, it increased the concentration of
most elements in leaves. Total N, P, and K concentrations followed this
trend; however, Ca was not affected by shading. Fruit dry matter content
declined slightly, from 5.9% to 5.7% of fresh weight, for plants grown
with no shade or shade with 50% transmittance, respectively. However,
there was no significant effect of shading on K, Ca, Mg, or on minor elements in fruit tissue, whether expressed on a fresh weight or dry weight
basis. Thus, shading a greenhouse to improve fruit quality had no effect
on the value of ripe tomatoes as a dietary source of mineral nutrients.
Trials were conducted in 2004 to compare the effects of soybean oil
formulations and concentrations on flowering and fruit thinning of
rabbiteye and southern highbush blueberries. Mature ‘Climax’ bushes
near Spring City, Tenn., were sprayed to runoff on 10 Feb. with water,
or 9% soybean oil in the formulations TNsoy11, TNsoy12, TNsoy13,
TNsoy14, or Golden Natur’l (GN). In a second trial, 3-year-old ‘Legacy’
southern highbush plants at Spring Hill, Tenn., were sprayed on 11
Feb. with 0%, 6%, 9%, 12%, and 15% GN. A similar trial was sprayed
on 5 Mar. at Fletcher, N.C., using young plants of various Southern
highbush cultivars. Each formulation of soybean oil (9%) delayed bud
development and flower anthesis of ‘Climax’ bushes. Bloom opening
on ‘Legacy’ bushes was delayed by 2 to 6 days with sprays of ≥9%
GN, with higher concentrations causing more delay. However, flower
bud mortality of ‘Legacy’ plants was greater when sprayed with the
higher oil concentrations. ‘Legacy’ plants sprayed with 0%, 6%, and
≥9% oil had 0%, 30% and ≥70% bud mortality, respectively, at 36
days after treatment. ‘Legacy’ plants sprayed with 12% and 15% oil
sprays had an estimated 24% and 13%, respectively, of a crop load
compared to the estimated 100% crop load on control plants. Flower
bud development, flower bud mortality, crop load and berry size (across
cultivars) of Southern highbush cultivars at Fletcher were not affected
by oil treatments. Results were variable among trials, perhaps due to
factors such as cultivars, timing of application (date), maturity of plants,
environmental conditions, etc. There is potential for soybean oil formulations to be used as a chemical thinner as well as to delay blooming.
(214) Brassinosteroid-induced Femaleness in Cucumber
and Relationship to Ethylene Production
(367) Symptom Expression of Mixed Virus Infections in
‘Chickasaw’ Blackberry
Ekaterina Papadopoulou, Rebecca Grumet*
Mark M. Bray*, John R. Clark, Rose C. Gergerich
Michigan State University, Horticulture, Plant and Soil Sciences Bldg., East Lansing,
MI, 48824
University of Arkansas, Horticulture, Fayetteville, AR, 72701
Connecticut Agricultural Experiment Station, Forestry and Horticulture, New Haven,
CT, 06511
The cucurbit family is noted for diversity in sex expression phenotypes.
HORTSCIENCE, VOL. 40(4), JULY 2005
final6_20July HS.indb 1057
POSTERS–WEDNESDAY
Knowledge of constitutive levels of gas exchange and antioxidant
properties under unstressed conditions is critical for elucidating their
potential roles in stress tolerance, planning cultural practices, and
evaluating nutritional quality of vegetable crops. This greenhouse
study reports gas exchange, photosystem II efficiency, and pigment and
antioxidant profiles of two spinach cultivars [Spinacia oleracea L., cvs.
Bloomsdale Long Standing (Bloomsdale) and Hybrid Tyee (Tyee)] with
contrasting morphology. ‘Bloomsdale’, the cultivar with more compact
stature and larger leaves, had 47% greater photosynthesis (Pnet) than
‘Tyee’. Stomatal conductance (gs) and transpiration (E) were 94% and
46% greater in ‘Bloomsdale’ than ‘Tyee’, respectively. However, photosystem II efficiency (Fv’/Fm’) was only 8% greater in ‘Bloomsdale’ than
‘Tyee’. Instantaneous water use efficiency was similar in both cultivars.
‘Bloomsdale’had nonsignificantly greater concentrations of chlorophylls
a and b, lutein, β-carotene and violaxanthin than ‘Tyee’. Both cultivars
had similar, marginal α-tocopherol concentrations (<0.1 ng·g-1 FW).
However, ‘Tyee’ had a greater chlorophyll a:b ratio which, combined
with lower gs and E, suggests a possible advantage for ‘Tyee’ over
‘Bloomsdale’ under relatively dry and high light conditions. Further
studies must be conducted to compare nutritional quality of the two
cultivars, based on constitutive levels of pigments and antioxidants.
Greater gas exchange activity in ‘Bloomsdale’ than ‘Tyee’ appears to
be due more to CO2 acquisition/metabolism than photosystem II efficiency or concentrations of pigments and antioxidants.
Typically, a phase of male flowers precedes the appearance of female
or hermaphrodite flowers. Sex determination of individual flowers is
regulated by genetic, environmental, and hormonal factors. Ethylene,
auxins, and gibberellins all influence flower sex, with ethylene, which
promotes femaleness, playing a predominant role. In this study, we
tested whether brassinosteroids, a more recently identified class of plant
hormones, also influence cucurbit sex expression. Applied epi-brassinolide (epi-BL) caused a significant decrease in time of appearance of
the first female flower on monoecious cucumber plants, and increased
total female flowers on the main stem. Increasing concentrations had a
stronger effect. Of the three species tested, cucumber, melon, and zucchini, cucumber was the most responsive. Application of epi-BL also
caused an increase in ethylene production by cucumber and zucchini
seedlings, suggesting that the BR effect may be mediated by ethylene.
To investigate the possible relationship between BR and ethylene on
sex expression, we identified the concentration of ethephon (5 ppm)
that caused an increase in ethylene production comparable to that
induced by 10 μM epi-BL (about two-fold). Treatment with 5 ppm
ethephon was sufficient to increase femaleness of cucumber plants,
but not zucchini plants, suggesting that the difference in response to
epi-BL may reflect differences in sensitivity to ethylene. Collectively,
our results indicate that application of brassinosteroids to cucumber
cause earlier and increased female flower production, and that the
effects may be mediated, at least in part, by brassinosteroid-induced
increased production of ethylene.
Latent infection of Blackberry yellow-vein associated virus (BYVaV)
in ‘Chickasaw’ blackberry has been reported. However, plants with
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characteristic leaf symptoms, such as vein yellowing, chlorotic
mottling, and oak-leaf patterns, have tested positive for BYVaV using
reverse-transcription polymerase chain reaction. Experiments were
initiated to determine if the symptoms expressed in BYVaV infected
‘Chickasaw’ were caused by mixed virus infections. BYVaV, a
recently identified crinivirus, was evaluated for synergistic interactions
with Tobacco ringspot virus (TRSV), Tomato ringspot virus (ToRSV),
and Raspberry bushy dwarf virus (RBDV). ‘Chickasaw’ blackberry
plants infected with BYVaV (single infection) were used as receptor
plants to establish mixed virus infections with TRSV and ToRSV
transmitted by nematodes and RBDV transmitted by bottle grafts.
Characteristic symptoms of multi-virus infection will be presented
and discussed.
(368) Effect of Four Weed Management Systems on Soil
Quality in June-bearing Strawberry Production
Craig Dilley*, Gail Nonnecke
Iowa State University, Horticulture, Ames, IA, 50011
Sustainable strawberry production depends on effective weed and soil
management. Alternative weed management strategies are needed because few herbicides are registered for use in matted-row strawberry
culture. Soil analyses are often measured in terms of chemical and
physical properties alone. Measuring biological indicators of soil quality that are sensitive to changes in the environment can enhance these
analyses. The experiment compared the effects of four weed management systems on weed growth, soil quality properties, and strawberry
yield, growth, and development. Treatments were killed-cover crop
mixture of hairy vetch (Vicia villosa) and cereal rye (Secale cereale);
compost + corn gluten meal + straw mulch; conventional herbicide;
and methyl bromide soil fumigation. Results indicated that there were
no differences in percentage of weed cover or number of strawberry
runners between the four weed management treatments in the planting
year (July or Aug. 2004). The soil quality parameters, infiltration rate,
soil bulk density, earthworm number, and total porosity were similar
for all treatments. Plots that received the straw mulch treatment had
a soil volumetric water content 20% higher and air-filled porosity
that was 26% higher than the average of other treatments. Although
treatment plots received similar N, leaf nutrient analysis showed that
plants receiving the straw mulch + corn gluten meal treatment had
a similar amount of total N when compared to the conventional and
methyl bromide treatments, but was 21% higher than the killed-cover
crop treatment.
(369) Field and Greenhouse Evaluation of Strawberry
Genotypes for Tolerance to Black Root Rot Pathogens
Chrislyn A. Drake*, James F. Hancock
Michigan State University, Horticulture, East Lansing, MI, 48824
Black root rot is a widespread disease of strawberry (Fragaria ×ananassa
Duchnesne) that causes the death of feeder roots and the degradation of
structural roots. The major causal organisms of black root rot include
Rhizoctonia fragariae Husain and W.E. McKeen, Pythium spp. and
Pratylenchus penetrans (Cobb) Filipjev and Schuurmans Stekhoven.
The current method of control for black root rot is methyl-bromide
fumigation; however, methyl bromide is scheduled to be phased out
in 2005, and its effects are short-lived in matted-row systems. The
objectives of the study were to measure levels of tolerance to black
root rot in 20 strawberry genotypes and to determine which pathogens
were present in the soil. The genotypes were planted in four blocks
each of methyl-bromide fumigated and nonfumigated soil, and were
evaluated for crown number, number of flowers per crown, yield, and
average berry weight over two years. The results showed that all three
pathogens were present in the field, and that there was a significant
genotype × fumigation interaction for yield and crown number in both
years. The cultivars Bounty, Cabot, and Cavendish, all released from the
breeding program in Nova Scotia, displayed tolerance to the pathogens
that cause BRR. Greenhouse studies were conducted using a subset of
the genotypes to determine if any one pathogen causes more damage
than others, and to determine if susceptibility to a particular pathogen
varies between genotypes.
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final6_20July HS.indb 1058
(370) In-row Plant Spacing Affects Early Season Fruit
Yield of Strawberry Grown in a Winter, Annual Hill
Production System
Craig K. Chandler*1, Daniel E. Legard2, Chang-Lin Xiao3,
James C. Mertely1
1
University of Florida, Gulf Coast Research and Education Center, Wimauma, FL,
33598; 2California Strawberry Commission, Research and Education, Watsonville, CA,
95077-0269; 3Washington State University, Tree Fruit Research and Extension Center,
Wenatchee, WA, 98801-1230
On standard two-row black polyethylene covered beds, ‘Camarosa’,
‘Rosa Linda’, and ‘Sweet Charlie’ strawberry plants were grown at 23,
31, 38, or 46 cm within-row spacing during the 1997–98 and 1998–99
seasons at Dover, Fla. Ripe fruit were harvested twice weekly from
December through March. The first 8 weeks of harvest was considered
the early period; the late period consisted of all harvests after the first 8
weeks. The effect of spacing on early marketable yield was consistent
across seasons and cultivars. The 23-cm spacing resulted in the highest
marketable yield per unit area, followed by the 31-, 38-, and 46-cm
spacing. The percentage of fruit that were small (unmarketable) was
higher at the 23-cm spacing than at the wider spacings (40% vs. 35%
or 36%), but spacing did not affect the percentage of fruit that were
misshapen. For the late harvest period, a spacing effect on marketable
yield occurred in 1998–99, but not in 1997–98. The 23-, 31-, and 38-cm
spacings in 1998–99 resulted in similar late period yields, which were
15% to 21% higher than the yield resulting from the 46-cm spacing.
These results indicate that marketable yields per plant during the late
period were higher at the wider spacings.
(371) Hydroponic Inoculation of Cranberry with Ericoid
Mycorrhizal Fungus
Piero A. Spada, Beth Ann A. Workmaster, Kevin R. Kosola*
University of Wisconsin, Madison, Horticulture, Madison, WI, 53706
Cranberry (Vaccinium macrocarpon) plants colonized with ericoid
mycorrhizal fungi are capable of utilizing organic nitrogen sources that
are unavailable to non-mycorrhizal plants. Despite the importance of
mycorrhizal colonization in the nitrogen nutrition of wild cranberry,
almost all measurements of cranberry nitrogen uptake and assimilation
have been carried out with non-mycorrhizal plants. We have found that
cranberry can be inoculated directly in solution culture. We cultured
the ericoid mycorrhizal fungus Hymenoscyphus ericae in liquid culture, harvested and rinsed hyphae, and added ≈200 mg fresh weight
hyphae per rooted cranberry cutting (cv. Stevens) growing in a modified
Johnson’s solution. After 6 weeks, newly developed roots were most
heavily colonized. We examined the effects of NH4+ concentration (5,
10, 20, 50, 100, and 500 μM NH4+) in solution on colonization rates.
Colonization (% root length) increased with increasing ammonium
concentration in solution, with maximum colonization at 50 and 100
μM NH4+; colonization was much lower at 500 μM NH4+. Cranberry
inoculated with H. ericae in solution culture will be used for analysis
of the effects of mycorrhizal colonization on uptake kinetics of NH4+,
NO3-, and amino acids.
(372) Water Requirements of Highbush Blueberry
Cultivars Planted at Normal and High Density Spacings
David Bryla*1, Bernadine Strik2
1
USDA ARS, Horticultural Crops Research Unit, Corvallis, OR, 97330; 2Oregon State
University, Horticulture,Corvallis, OR, 97331
Many growers in the Pacific Northwest are planting blueberry fields at
higher densities to improve yields and increase the number of berries
harvested per acre in the first few years after planting. The objective
of this study was to determine the effect of high-density planting on
blueberry water requirements. Although close spacing reduces individual
plant size, we expected that plants spaced closer together would require
more irrigation per unit land area than those spaced further apart due to
increased canopy coverage within rows. The study utilized a 5-year-old
planting of highbush blueberry, consisting of three cultivars, ‘Duke’,
‘Bluecrop’, and ‘Elliott’, planted at 0.5- and 1.2-m in-row spacings.
Plant water use was calculated from changes in soil water content
HORTSCIENCE, VOL. 40(4), JULY 2005
6/20/05 5:02:09 PM
measured using TDR probes for shallow depths and a neutron probe
and access tubes for deeper depths. Stem water potentials were also
measured periodically using a pressure chamber to determine how well
irrigation was meeting crop water demands throughout the season.
Surprisingly, plants spaced 0.5 m apart required only slightly more
water than those spaced 1.2 m apart. They did, however, require more
frequent irrigations due to their smaller root systems, especially during
fruit filling. Water use by each cultivar increased during fruit filling and
then rapidly decreased after harvest. ‘Duke’ required the most water
among cultivars, using 5–10 mm/day from mid-May to mid-August,
while ‘Elliott’ required the least, using 3–5 mm/day.
(373) Use of Calcium Foliar Feed Fertilization to Reduce
Rain-related Splitting in Rabbiteye and Southern
Highbush Blueberry
Donna A. Marshall*1, James M. Spiers1, Kenneth J. Curry2
1
2
USDA-ARS, Small Fruit Research Service, Poplarville, MS; University of Southern
Mississippi, Biological Sciences, Hattiesburg, MS, 39426
Calcium is commonly known to affect the developmental processes
of many plants, and its role as a major nutrient has been interpreted in
terms of its interaction with components of the cell wall and membrane.
A 2-year study was conducted to assess the affects of calcium foliar feed
fertilization applied at bloom and throughout floral development on the
reduction of rain-related splitting in blueberries. Foliar-applied calcium
at 0.2% or 0.9% concentration did not successfully decrease splitting
in blueberries to a statistical and, more importantly, an economically
significant level. Calcium sprays also had no adverse affects on the fruit
firmness, quality, or calcium concentrations within the fruit.
Jeffrey G. Williamson*, E. Paul Miller
University of Florida, Horticultural Sciences Department, Gainesville, FL, 32611
Bearing ‘Misty’ and ‘Star’ southern highbush blueberries were grown
on pine bark beds and fertilized at three rates using granular and liquid
fertilizers with a 3–1–2 (1N–0.83K–0.88P) ratio. Granular fertilizer
was applied 8 times per year at 4-week intervals beginning in April
and continuing through October. Liquid fertilizer was applied with
low volume irrigation 16 times per year at 2-week intervals during the
same period. During the growing season, irrigation was applied at 2- to
3-day intervals in the absence of rain. A 2 cultivar × 2 fertilizer type
× 3 fertilizer rate factorial arrangement of treatments was replicated 8
times in a randomized complete-block design. All fruits were harvested
from single-plant plots at 3- to 4-day intervals. Canopy volume was
not affected by fertilizer type, but fruit yield was slightly greater for
granular than for liquid fertilizer treatments. In 2003, fruit yield of
2.5-year-old ‘Misty’ and ‘Star’ plants increased with increasing fertilizer rates up to the highest rate tested (50 g N/plant/year). Similarly,
in 2004, fruit yields increased with increasing fertilizer rates up to the
highest rate (81 g N/plant/year). Root distribution was limited to the
12-cm-deep layer of pine bark with very few roots penetrating into the
underlying soil. The positive growth responses of blueberry plants to
high fertilizer rates in pine bark beds suggests that soluble fertilizer
was leached through the pine bark layer into the soil below the root
zone. More frequent, lighter applications of soluble fertilizers, use of
slow-release or controlled-release fertilizers, and careful irrigation
management may improve fertilizer use efficiency of blueberry plantings on pine bark beds.
(375) Highbush Blueberry Cultivar Evaluation in South
Central Missouri Mineral Soil
Martin L. Kaps*, Patrick L. Byers
Southwest Missouri State University, Fruit Science, Mountain Grove, MO, 65711
Fourteen highbush blueberry cultivars are being evaluated in south
central Missouri mineral soil. This soil is often not ideal for culture of
highbush blueberry. The planting site was initially pH 6.3 with a 92%
base saturation on the cation exchange capacity. Sulfur additions, and
summer and fall cover cropping were done for 2 years prior to planting
HORTSCIENCE, VOL. 40(4), JULY 2005
final6_20July HS.indb 1059
(376) Carbon Mobilization and Yield Components in
Raspberry
Horacio E. Alvarado*, Rebecca L. Darnell, Jeffrey G. Williamson
University of Florida, Horticultural Sciences, Gainesville, FL, 32611
Raspberry root growth during fruiting appears to be a strong sink for
assimilates, and may decrease carbon availability for fruits and, consequently, cane yield. Both floricanes and primocanes may contribute to
root carbon supply in raspberry during fruiting. To test this, ‘Tulameen’
raspberry canes were grown outdoors in containers filled with perlite
and peat (1:1). One-half of the plants were girdled and the rest were
nongirdled. Within each girdling treatment, either 0 or 3 primocanes
were allowed to grow. Treatments were applied at early bloom (10
May), and 50% fruit harvest occurred the first week in June. Fruit number and yield per plant decreased in girdled plants and plants without
primocanes compared with nongirdled plants and plants with primocanes. Individual fruit fresh weight was not affected by treatments, but
individual fruit dry weight and the dry weight to fresh weight ratio was
higher in girdled plants without primocanes than in the other treatments.
Neither girdling nor the presence of primocanes affected dry weight
allocation to primocanes or floricanes. Root dry weight was higher
in girdled plants with primocanes than in nongirdled plants without
primocanes. It appears that primocanes supply carbon to roots during
fruiting, and subsequently, roots mobilize carbon to floricanes. Thus,
roots appear to serve primarily as a translocation pathway for carbon
from primocanes to floricanes. However, when primocane growth is
suppressed, root carbon is mobilized to support floricane development.
If carbon flow from roots to floricanes is restricted, fruit number and
yield is significantly decreased.
POSTERS–WEDNESDAY
(374) Fertilization of Southern Highbush Blueberries on
Pine Bark Beds
to lower soil pH (5.3) and increase organic matter content. Four replications of three plants were set in a randomized complete block in early
Apr. 1998. Plant spacing is 1.2 × 3.0 m on bermed rows that are mulched
with chipped hardwood. Acidified irrigation water is supplied through
drip lines. Fertilizer is applied annually both as dry ammonium sulfate
and soluble nitrogen through drip lines at 84 kg·ha-1 N. Cumulative
yield per bush after the first five harvest seasons showed ‘Bluecrop’,
‘Brigitta Blue’, ‘Chandler’, ‘Darrow’, ‘Legacy’, ‘Nelson’, and ‘Reka’
at 17 to 21 kg; ‘Duke’, ‘Nui’, ‘Ozarkblue’, and ‘Sierra’ at 14 to 15 kg;
and ‘Collins’, ‘Summit’, and ‘Toro’ at 9 to 10 kg. Berry weight averaged 2 g with a low of 1.4 g (‘Reka’) to a high of 3.3 g (‘Chandler’).
Plant height averaged 155 cm with a low of 117 cm (‘Nui’) to a high of
188 cm (‘Legacy’, ‘Nelson’). Cultivars in the two higher yield groups
were recommended to Missouri growers for planting.
Poster Session 38—Ornamentals/Landscape and TurfMineral Nutrition/Pest Management/Stress Physiology
20 July 2005, 1:15–2:00 p.m.
Poster Hall–Ballroom E/F
(344) Effects of Ozone-treated Irrigation Water on
Vegetative Growth of Chrysanthemum
Garry V. McDonald*1, Michael A. Arnold1, Bruce J. Lesikar2,
Larry W. Barnes3, Don C. Wilkerson1
1
Texas A&M University, Horticultural Sciences, College Station, TX, 77843-2133; 2Texas
A&M University, Biological and Agricultural Engineering; 3Texas A&M University, Plant
Pathology and Microbiology
An experiment was initiated in June and Aug. 2004 to determine affects
of ozonated fertilizer–injected water on plant growth of chrysanthemum (Chrysanthemum × morifolium T. de Romatuelle ‘Covington’).
Aliquots (20 L) of reverse osmosis water were amended with 0, 50, and
300 mg·L-1 N (21N–3.1P–5.8K) water-soluble fertilizer and exposed
to ozone (O3) gas for 0, 30, 60, or 120 s at a flow rate of 300 mL/min.
Containers were sealed and allowed to set for 15 min for O3 diffusion.
Treated water was used to irrigate plants. Plants were in 10.2-cm pots
and grown until floral initiation. Plants were harvested on 12 Aug.
2004 or 24 Nov. 2004. Growth index (height x canopy width × canopy
width in a perpendicular direction/3), and shoot and root dry masses
were determined. Interactions between fertility concentration and
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ozone exposure rates were nonsignificant (P ≤ 0.05). Significant main
effect differences occurred in growth index and shoot/root dry masses
in response to fertilizer concentrations, but growth measures were not
affected by ozone exposure. Peak ozone concentrations in fertilizerinjected irrigation water averaged 0.21 mg·L-1 O3 (120 s exposure at
300 mL·L-1) after 15 min diffusion time. At 20 min diffusion times,
ozone levels dropped to 0 mg·L-1. No gross morphological differences or
obvious necrosis typical of ozone damage on chrysanthemum occurred
at any O3 exposure level. No observable nutritional deficiencies were
noted. Vegetative growth of chrysanthemum was not directly injured
by irrigation water that was exposed to ozone gas for 0 to 120 s at a
300 mL/min flow rate.
(345) Mushroom Farm and Anaerobic Digestion
Wastewaters as Supplemental Fertilizer Sources for
Growing Container Nursery Stock
C. Chong*1, P. Purvis1, G. Lumis1, B.E. Holbein2, R.P. Voroney1,
H. Zhou3, H.-W. Liu2
1
University of Guelph, Dept. of Plant Agriculture, Bovey Building, Guelph, Ont., Canada;
Super Blue Box Recycling Corporation, Etobicoke, Ont., Canada; 3University of Guelph,
School of Engineering, Guelph, Ont., Canada
2
Wastewaters from farm and composting operations are often rich in
certain nutrients that can be reutilized in crop production. Liners of
silverleaf dogwood (Cornus alba L. ‘Argenteo-marginata’), common
ninebark [Physocarpus opulifolius (L.) Maxim.], and ‘Anthony Waterer’
spirea (Spiraea ×bumalda Burvenich) were grown in 6-L containers
filled with a medium consisting of 73% bark, 22% peat, and 5% pea
gravel, by volume. Plants were fertigated daily via a computer-controlled
multi-fertilizer injector with three recirculated fertilizer treatments: 1)
a stock solution with macro- and micronutrients, electrical conductivity
(EC) 2.2 dS·m-1; 2) wastewater from a mushroom farm; and 3) process
wastewater from anaerobic digestion of municipal solid waste. The
wastewaters used in both treatments 2 and 3 were diluted with tap
water, and the computer was programmed to amend, dispense, and
recirculate nutrients, based on the same target EC as in treatment 1. For
comparison, there was a traditional controlled-release fertilizer treatment
[Nutryon 17–5–12 (17N–2P–10K) plus micronutrients incorporated into
the medium at a rate of 6.5 kg·m-1, nutrients not recirculated]. All three
species responded similarly to the three recirculated fertilizer treatments.
Growth in the recirculated treatments was similar and significantly
higher than that obtained with controlled-release fertilizer. A similar
trend in EC was observed in the media near harvest. Throughout the
study, there was no sign of nutrient toxicity or deficiency with any of
the species or treatment.
(346) Effect of Rhizosphere pH on Root Growth of Two
Landscape Species
Amy N. Wright*1, Robert D. Wright2, Brian E. Jackson1,
Jake A. Browder2
1
Auburn University, Horticulture, 101 Funchess Hall, Auburn, AL, 36849; 2Virginia Tech,
Horticulture, Saunders Hall, Blacksburg, VA, 24061
Rhizosphere pH preferences vary for species and can dramatically influence root growth rates. Research was conducted to determine the effect
of root zone pH on the root growth of Buxus microphylla Sieb. & Zucc.
‘Green Beauty’ (boxwood) and Kalmia latifolia L. ‘Olympic Wedding’
(mountain laurel). Boxwood plants removed from 3.8-L containers and
mountain laurel plants removed from 19-L containers were situated
in the center of separate Horhizotrons™. The key design feature of the
Horhizotron is four wedge-shaped quadrants (filled with substrate) that
extend away from the root ball. Each quadrant is constructed from glass
panes that allow the measurement of roots along the glass as they grow
out from the root ball into the substrate. For this experiment, each quadrant surrounding a plant was filled with a pine bark substrate amended
per m3 (yd3) with 0.9 kg Micromax (Scotts-Sierra, Marysville, Ohio)
and 0, 1.2, 2.4, or 3.6 kg dolomitic limestone. All plants received 50 g
of 15N–3.9P–9.8K Osmocote Plus (Scotts-Sierra), distributed evenly
over the surface of the root ball and all quadrants. Plants were grown
from May to Aug. 2003 in a greenhouse. Root lengths were measured
about once per week throughout the experiment. Root length increased
1060
final6_20July HS.indb 1060
linearly over time for all species in all substrates. Rate of root growth
of boxwood was highest in pine bark amended with 3.6 kg·m3 lime
and lowest in unamended pine bark. Rate of root growth of mountain
laurel was lowest in pine bark amended with 3.6 kg·m3 lime. Results
support the preference of mountain laurel and boxwood for acidic and
alkaline soil pH environments, respectively.
(347) Identifying Common Reflectance Properties
in Diverse Ornamental Species to Nondestructively
Determine Nitrogen Status
Jonathan M. Frantz*1, Dharmalingam S. Pitchay2, Glen Ritchie3,
Heping Zhu4
1
ARS, USDA, Toledo, OH, 43606; 2University of Toledo, Department of Biological
Sciences, Toledo, OH, 43606; 3University of Georgia, Coastal Plain Experiment Station,
Tifton, GA, 31794; 4ARS, USDA, Wooster, OH, 44691
Nitrogen (N) is often supplied to plants in excess to minimize the possibility of encountering N deficiency that would reduce the plant quality
due to leaf chlorosis and necrosis. This is not only costly, but it can
reduce the quality of plants, predispose the plants to biotic stress such
as Botrytis gray mold, and extend the production cycle. Several tools
can be used to identify N deficiency in plants, and most are based on
chlorophyll reflectance or transmittance. While sensitive when plants
are experiencing N deficiency, spectral signals can saturate in an ample
N supply and make it difficult to discern sufficient and supra-optimal
N nondestructively. Three diverse ornamental species (begonia, Begoniaceae ×tuberhybrida; butterflybush, Buddleja davidii; and geranium,
Pelargonium ×hortorum) were grown with a broad range of N supplied
(1.8 to 58 mM) in three separate studies that resulted in a range of 1.8%
to 6% tissue N concentration. Using a spectroradiometer, we measured
reflectance from the whole plants twice over a period of 3 weeks. A
first-derivative analysis of the data identified six wavebands that were
strongly correlated to both begonia and butterflybush tissue N concentration (r2 ~ 0.9), and two of these also correlated well to geranium N
concentration. These wavebands did not correlate to chlorophyll peak
absorbance, but rather blue, green, red, and far-red “edges” of known
plant pigments. These wavebands hold promise for use as a nondestructive indicator of N status over a much broader range of tissue N
concentration than current sensors can reliably predict.
(348) Geranium Nutrient Deficiency Symptoms,
Partitioning, and Bioenergetic Costs of Construction
Dharmalingam S. Pitchay*1, Jonathan M. Frantz2, James C. Locke2
1
University of Toledo, Department of Biological Sciences, Toledo, OH, 43606; 2ARS,
USDA, Toledo, OH, 43606
Geranium (Pelargonium ×hortorum) is considered to be one of the topselling floriculture plants, and is highly responsive to increased macroand micronutrient bioavailability. In spite of its economic importance,
there are few nutrient disorder symptoms reported for this species. The
lack of nutritional information contributes to suboptimal geranium
production quality. Understanding the bioenergetic construction costs
during nutrient deficiency can provide insight into the significance of
that element predisposing plants to other stress. Therefore, this study
was conducted to investigate the impact of nutrient deficiency on plant
growth. Pelargonium plants were grown hydroponically in a glass
greenhouse. The treatment consisted of a complete modified Hoagland’s
millimolar concentrations of macronutrients (15 NO3-N, 1.0 PO4-P, 6.0
K, 5.0 Ca, 2.0 Mg, and 2.0 SO4-S) and micromolar concentrations of
micronutrients (72 Fe, 9.0 Mn, 1.5 Cu, 1.5 Zn, 45.0 B, and 0.1 Mo)
and 10 additional solutions each devoid of one essential nutrient (N, P,
Ca, Mg, S, Fe, Mn, Cu, Zn, or B). The plants were photographed and
divided into young, maturing, and old leaves, the respective petioles,
young and old stems, flowers, buds, and roots at “hidden hunger,”
incipient, mid- and advanced-stages of nutrient stress. Unique visual
deficiency symptoms of interveinal red pigmentation were noted on
the matured leaves of P- and Mg-deficient plants, while N-deficient
plants developed chlorotic leaf margins. Tissue N concentration greatly
influenced bioenergetic construction costs, probably due to differences
in protein content. This information will provide an additional tool in
producing premium geraniums for the greenhouse industry.
HORTSCIENCE, VOL. 40(4), JULY 2005
6/20/05 5:02:12 PM
(349) Fertilizer-N Effects on Cycas–Nostoc Symbiosis
Laura M.R. Rinaldi*1, Maria C. Margheri2, Alba Ena2
1
CNR, IVALSA, Via Madonna del Piano, Sesto Fiorentino, Firenze, 50019, Italy; 2CNR,
ISE, Firenze, Italy
(350) A Water-wise Plant Recognition Program for Utah
Rick Heflebower*1, Teresa Cerny-Koenig2, Molly Waters3,
Ruby Ward4
1
Utah State University, Extension, St. George, UT, 84770; 2Washington State University,
Horticulture and Landscape Architecture; 3State of Utah, Utah Division of Water Resources;
4
Utah State University, Economics Department
A cooperative program to recognize water-wise plants for Utah
landscapes was developed by 10 horticulture and water organizations
throughout the state. Representatives from each of the organizations
met to develop a plant list containing woody and ornamental species
that were attractive in the landscape, water conserving, adapted to the
climate, and available in the industry. A yellow tag with the words
“water- wise plant” outlined by the state of Utah was designed by the
committee and used to identify the plants. Tags were provided at no
cost to garden centers due to the funding of the organizations. A survey
conducted at the end of the first season gave very favorable results.
Sixty-seven percent of the participating nurseries indicated they would
“definitely” participate in the program again, and 27% indicated they
“probably” would participate. The Water-Wise Plant Tagging Program
serves as a model of how universities, governmental agencies, and private
businesses can work together to accomplish a common goal.
(351) Production of Rhododendron delavayi Franch.
Gu Zhanying*1, Chen Xun1, Wu Huamei2
1
Central South Forestry University, Resource and Environment College, Changsha, Hunan,
410004, China; 2Institute of Biology, Plant Biology Experiment Base
Rhododendron delavayi Franch. is an evergreen tree up to 5 m tall. Since
few tree rhododendron are available in the market, the demand for this
plant is high. Unfortunately, the supply is limited due to production
difficulty. Under natural conditions (control), seed germination rates
were 3% to 5%. When a special propagation bed was set up with mixed
media of humus, loess, and sand, the germination rate reached 75% if
the temperature was set from 20–25 °C, humidity was 80% to 90%, and
irrigation water pH was 6–-6.5. In growing Rhododendron delavayi,
medium pH, water-holding capacity, aeration, and organic matter were
considered. The medium, mixed with cinder, loess, humus, and perlite,
yielded a 95% survival rate and the tallest plants. To produce aestheti-
HORTSCIENCE, VOL. 40(4), JULY 2005
final6_20July HS.indb 1061
Poster Session 39—Herbs, Spices, and Medicinals 2
20 July 2005, 1:15–2:00 p.m.
Poster Hall–Ballroom E/F
(398) Basil Competition Above and Below Ground with
Livid and Smooth Amaranths
J. Pablo Morales-Payan*, William M. Stall
University of Florida, Horticultural Sciences Department, Gainesville, FL, 32611-0690
Competition partitioning experiments were conducted to determine
the extent of shoot and root interference between sweet basil (Ocimum
basilicum) and the weeds smooth amaranth (Amaranthus hybridus)
and livid amaranth (A. lividus). Sweet basil and amaranths were grown
for 45 days in plastic 19-L containers filled with fertilized sandy soil.
The plants were grown: 1) individually (one plant per container = no
interference); 2) one basil plant and one amaranth plant together in
the same container (= full interference); 3) one basil plant and one
amaranth plant together in the same container, training the shoots apart
to avoid canopy contact (= below ground interference); or 4) basil
and amaranth grown in different containers set side by side (= above
ground interference). Each basil/amaranth treatment was replicated five
times and the experiment was conducted twice. The effects of smooth
and livid amaranths on basil yield were the same for a given type of
interference (full, above ground, below ground). Full interference
from amaranth reduced basil shoot yield by about 35%, as compared
to the yield of basil with no interference from amaranth. The effects
of above-ground and below-ground interference on basil yield were
additive, but interference above ground had a greater impact (about
21% basil yield loss) than below ground interference (about 14% basil
yield loss). These results show that smooth and livid amaranths may
drastically reduce sweet basil shoot yield, and that amaranth interference with sweet basil occurred to a greater extent above ground than
below ground.
POSTERS–WEDNESDAY
Cycas revoluta Thunb., cultivated as an ornamental plant for indoor
and outdoor use, is characterized by an extremely slow rate of growth.
In spite of the occurrence in its coralloid roots of the nitrogen-fixing
cyanobiont Nostoc, N fertilization is commonly used to accelerate
Cycas growth. A greenhouse experiment was conducted to examine
the effects of two forms of combined N on growth of Cycas plants
and cyanobacterial nitrogenase activity, measured on intact plants.
Cycas plants grown in pots were fertilized from June to September
with nutrient solution containing macronutrients as P, K, Mg, and
Hoagland’s micronutrients. N (700 mg/plant ) was supplied as KNO3,
or applied as NH4NO3; control plants received nutrient solution
without nitrogen. Treatments were applied monthly and repeated for
three times. Each treatment consisted of 15 plants. The length of the
new leaves was recorded during the growth cycle of the plants. The
nitrogenase activity, based on acetylene reducing activity (ARA), was
measured on the plants in situ in July and in October. N fertilization
stimulated both the nitrogenase activity and the growth of the plants.
In comparison with the control, average increases in ARA of more
than 20% were observed in the treated plants. Nitrogenase activity
was slightly better in the presence of NH4NO3 in July, whereas the
values measured in October were about the same for two treatments.
The two forms of nitrogen were the same also regarding the stimulus
on growth: in N-treated plants the total length of the new leaves was
more than double with respect to the control at the end of the growing
season. Control plants grown without fertilizer N had a slow start to
their growth cycles and were unable to recover and compensate later
for the lack of transient N.
cally pleasing plants with flowers, apical dominance was removed
and the growth of lateral buds was promoted by pinching the terminal
buds of the seedlings in their second year. Also, 3N–1P–1K fertilizer
should be used to increase seedling growth. With proper pruning, the
seedlings were flowering and ready for market in 3–4 years (instead
of 8 years under natural conditions). The acceptable germination rate,
better growing conditions, and feasible cultural practices should enable growers to produce quality plants, which ultimately enhance the
popularity of Rhododendron delavayi.
(399) Amino Levulinic Acid Effects on Basil Competition
with Slender Amaranth
J. Pablo Morales-Payan*, William M. Stall
University of Florida, Horticultural Sciences Department, Gainesville, FL, 32611-0690
Experiments were conducted to determine the effect of the biostimulant amino levulinic acid (5-ALA) on canopy and root competition of
transplanted sweet and purple basils with the weed slender amaranth
(Amaranthus viridus). Before transplanting, basil plants were sprayed
with an aqueous solution of 5-ALA (0 and 15 mg·L-1 a.i.). Basil and
amaranth were grown in plastic 19-L containers either: 1) individually
(one plant per container = no interference); 2) one basil plant and one
amaranth plant together in the same container (= full interference); 3)
one basil plant and one amaranth plant together in the same container,
training the shoots apart to avoid canopy interference (= below ground
interference); or 4) basil and amaranth grown in different containers
set side by side (= above ground interference). When 5-ALA was not
applied, full-interference from slender amaranth reduced sweet basil
shoot yield by 33%, and purple basil shoot yield by 48%. Above
ground interference from slender amaranth was about 65% of the total
interference effect. Basil plants treated with 5-ALA were less affected
by amaranth interference than untreated basil plants, but the magnitude
of the 5-ALA effect was greater in sweet basil than in purple basil.
5-ALA increased the yields of weed-free sweet basil and purple basil
by about 15% and 10%, respectively.
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6/20/05 5:02:14 PM
(400) Basil Yields Were Affected by Production Systems
and Environmental Control Strategies in a Retractable
Roof Greenhouse
caused elongation of internodes and a reduction in the number of leaves
in comparison with control and red-light treated plants. Essential oil
production was highest in plants grown under far-red light treatments.
Jennifer Nelkin, Ursula Schuch*
(403) Rosmarinic Acid (RA) Content in Leaves and Callus
of Five Different Rosemary Genotypes
University of Arizona, Plant Sciences, Forbes Bldg. Tucson, AZ, 85721
Fresh weight production of basil (Ocimum basilicum ‘Genovese’)
growing in a retractable roof greenhouse (RRGH) or outdoors was
evaluated under different shade environments, cultural production
systems, and roof control strategies in a semi-arid climate. Cultural
production systems included raised beds and towers consisting of six
pots arranged vertically and stacked on edge. The growing substrate
in both systems was perlite. The three shade environments included a
RRGH with either a clear woven roof (35% shade) or a white woven
roof (50% shade), or outdoors in full sun (0% shade). Within the RRGH,
three strategies of roof control were tested based on air temperature
thresholds, quantum thresholds, and globe thermometer temperature
thresholds. After establishment, plants were grown for 4 weeks, each
under the three roof control strategies in each environment and in both
cultural systems. New shoots were harvested weekly and fresh weights
were determined. Overall, fresh weight per plant was significantly affected by cultural production system, and basil grown in raised beds
produced twice the biomass compared to plants grown in vertical towers. Productivity of basil grown in raised beds was not affected by the
three shade environments, but plants in vertical towers produced about
20% more when grown in full sun or under 35% shade compared to
under 50% shade. Within the RRGH, roof control strategy significantly
affected basil fresh weight per plant. Roof control, based on either a
quantum sensor or globe thermometer, increased production by 31%
compared to air temperature control. Greater productivity was related
to higher cumulative light exposure of plants. Quality of basil grown
in the RRGH was superior to that grown in full sun.
Hany M. El Naggar*1, Paul E. Read1, Susan L. Cuppett2
1
University of Nebraska-Lincoln, Agronomy and Horticulture Dept., Lincoln, NE, 68503;
University of Nebraska-Lincoln, Food Science and Technology, Lincoln, NE, 68583
2
Rosemary (Rosmarinus officinalis) belongs to the Lamiaceae family, and is native to the Mediterranean and one of the most important
medicinal herbs containing antioxidants in its leaves. One of the most
important antioxidants is rosmarinic acid (RA). The aim of this study
was to test the concentration of (RA) and chlorophyll content in leaves
and callus of five successive subcultures of five different genotypes of
rosemary. They were: 1) ‘Majorca’; 2) Rosmarinus officinalis; 3) ‘Pine
Scented’; 4) ‘Madeline Hill’, and 5) APR. It was found that the highest
concentration of RA in leaves was in ‘Pine Scented’, while the lowest
concentration was for APR and ‘Madeline Hill’. However, in the callus the highest RA concentration was for Rosmarinus officinalis in the
second subculture and ‘Madeline Hill’ in the third subculture, while the
lowest RA concentration was for ‘Majorca’, ‘Pine Scented’, and APR.
The RA concentration in callus declined after the second and the third
subculture for Rosmarinus officinalis and ‘Madeline Hill’, respectively.
We concluded that it is preferred to use ‘Pine Scented’ for RA extraction from the leaves while for RA extraction from callus it is better to
use Rosmarinus officinalis in the second subculture or ‘Madeline Hill’
in the third subculture.
(404) Effect of Seed Source, Light during Germination,
and Cold-moist Stratification on Seed Germination in
Three Species of Echinacea
(401) Broadleaf Cilantro (Eryngium foetidum) Growth as
Affected by Selected Organic Biostimulants
Fredy R. Romero*, Kathleen Delate, David J. Hannapel
J. Pablo Morales-Payan*, William M. Stall
With the increase in popularity of echinacea as a botanical supplement,
organic production of this herb continues to grow. Echinacea seeds
typically show a high percentage of dormancy that can be broken by
ethephon or gibberellic acid, but these methods are not accepted in organic
production. We examined in three experiments the effects of varying seed
source and germination conditions on echinacea growth. To determine
the efficacy of nonchemical treatments, we evaluated the effect of light
with and without cold-moist stratification on seed germination of the
three most important medicinal species of echinacea, E. angustifolia,
E. purpurea, and E. pallida . We used cold-moist stratification under
24 h light, 24 h dark, and 16/8 h (light/dark) to break seed dormancy.
We found that germination was enhanced in seeds from a commercial
organic seed source, compared to a public germoplasm source. When
seeds were not cold-moist stratified, light increased germination in E.
angustifolia only, suggesting differential dormancy among the three
species. We found that when seeds were cold-moist stratified under
16–24 h of light for 4 weeks, the percentage and rate of germination
increased 10% over the control, suggesting this method as an alternative
to chemical seed treatments.
University of Florida, Horticultural Sciences Department, Gainesville, FL, 32611-0690
Experiments were conducted to determine the effects of a Siberian
fir (Abies sibirica) extract rich in triterpenic acid (TTA), a seaweed
(Ascophyllum nodosum) extract with cytokinin-like activity (CSE),
and a mixture of amino acids and short-chain peptides from fermented
animal tissue (APC) on broadleaf cilantro (Eryngium foetidum) shoot
weight and leaf area. Aqueous solutions of CSE, TTA, and APC at various rates were applied individually on the broadleaf cilantro leaves 15
and 30 days after transplanting. Broadleaf cilantro leaf area and shoot
fresh and dry weights were determined after harvest (60 days after
transplanting). APC, TTA, and CSE significantly increased broadleaf
cilantro shoot weights and leaf area as compared to control plants.
Aqueous solutions of APC at the rate of 900 g·L-1, CSE at the rate of
50 mg·L-1, and TTA at the rate of 300 mg·L-1 resulted in the highest
broadleaf cilantro shoot weights.
(402) Effect of Light Quality on Growth and Essential Oil
Composition in Rosemary
Giuliana Mulas, Lyle E. Craker*
University of Massachusetts, Medicinal Plant Program, Amherst, MA, 01003
Variation in light quality is known to modify plant morphology, growth,
and chemical constituency in plants. In the present study, the effect of
light quality on growth and essential oil composition in rosemary (Rosmarinus officinalis L.) was investigated by comparing plants receiving
supplemental red (660 nm) and far-red (730 nm) with each other and
with control plants not receiving supplemental light. Except for the
supplemental light treatments, all plants were grown under natural light
conditions in a greenhouse and received full daylight, averaging 9.23
h/day during the study. The red and far-red light treatments, given as
day extensions, started daily 15 min before sunset and continued for 4
h each evening for 4 weeks. No significant differences were observed
in biomass yield from the different light treatments, but far-red light
1062
final6_20July HS.indb 1062
Iowa State University, Horticulture, Ames,IA 50011
(405) Regeneration of Venus Fly Trap (Dionaea muscipula
Ellis) from Leaf Culture
Khalid M. Ahmad*, Syed M.A. Zobayed, Praveen K. Saxena,
David M. Hunter
Univ. of Guelph, Plant Agriculture, Ontario Agriculture College, Guelph, Ontario, Canada
Dionaea muscipula Ellis commonly known as Venus fly trap is an important carnivorous plant with medicinal importance. It contains certain
secondary metabolites like naphthoquinones and is used in anti-aid and
anti-cancer drugs and other medicines like Cornivora. Increasing interest
and use as an ornamental and medicinal plant, and dietary supplement
have put it in an endangered state. Development of in vitro techniques
for the preservation of germplasm that is on the brink of extinction is
highly demanded. A regeneration protocol for the multiplication and
micropropagation of Dionaea muscipla Ellis was established. In vitro
HORTSCIENCE, VOL. 40(4), JULY 2005
6/20/05 5:02:15 PM
regeneration potential of leaf explants in different concentrations and
combinations of plant growth substances was investigated in this study.
Seeds were grown and leaf disc explants were excised and cultured
under aseptic conditions on nutritional medium containing half strength
Murashige and Skoog (MS) mix with combinations of 1.0–20.0 μM BA,
2.5.0 μM IBA, 1.0–10.0 μM 2iP and 0.1–0.5μM TDZ. The cultures were
kept in growth cabinet with cool white light (40–60 μmol·m-2·s-1) under
16-h photoperiod. Regeneration was recorded after 60 days with the
intervals of 15 days based on the degree of shoot organogenesis and
somatic embryogenesis. 1/2 MS + 0.1 TDZ appeared to be efficient for
somatic embryogenesis and simple MS for direct shoot organogenesis.
1/2 MS combined with 2iP appeared to be efficient for regeneration
either by direct shoot organogenesis or by somatic embryogenesis. Plants
were rooted well in Cape Cundew medium. These investigations will
aid in the development of a model system for clonal mass propagation
and in vitro regeneration of Dionaea muscipla Ellis.
(406) A Comprehensive Echinacea Germplasm Collection
Located at the North Central Regional Plant Introduction
Station, Ames, Iowa
Joe-Ann McCoy*, Mark Widrlechner, Jeff Carstens
USDA/ARS & ISU, Agronomy, USDA/ARS North Central Regional Plant Introduction
Station, Iowa State University, Ames, IA, 50011-1170
(407) Tropical Spiderwort (Commelina benghalensis)
Density and Time of Emergence Effects on Cilantro Yield
J. Pablo Morales-Payan*, William M. Stall
University of Florida, Horticultural Sciences, Gainesville, FL, 32611-0690
The effect of density and time of emergence of the weed tropical spiderwort (Commelina benghalensis) (TS) on cilantro (Coriandrum sativum)
yield were determined in a field experiment in Citra, Fla. TS (0, 1, 2, and
4 plants per m2) emerged at 0, 1, 2, 3, or 4 weeks after cilantro emergence
(WACE) and allowed to grow with the crop for the remainder of the
season. No significant yield loss was detected when TS emerged 4 WACE.
Season-long competition with 1, 2, and 4 TS plants per m2 resulted in
yield loss of 27%, 44%, and 65%, respectively. Cilantro yield was reduced
by <10% when TS emerged 3 WACE or later, regardless of TS density.
Poster Session 40—Marketing/Consumer Horticulture/
Human Issues
20 July 2005, 1:15–2:00 p.m.
Poster Hall–Ballroom E/F
(151) Extension Outreach for Hispanic Workers: Ohio
and Beyond
Alejandra Acuna*, Hannah Mathers, Pope Jennifer
The Ohio State University, Horticulture & Crop Science, Columbus, OH, 43210
In 1998, the wholesale nursery industry represented the largest sector in
HORTSCIENCE, VOL. 40(4), JULY 2005
final6_20July HS.indb 1063
(152) The Effect of Live Plants and Window Views on
Employee Job Satisfaction
Andrea K. Dravigne*1, Tina M. Waliczek1, Jayne M. Zajicek2,
R. Daniel Lineberger2
1
Texas State University, Department of Agriculture, San Marcos, TX, 78666; 2Texas A&M
University, Department of Horticultural Science, College Station, TX, 77843-2133
The purpose of this study was to determine the effect of the presence
of live interior plants or window views of exterior green spaces on
employee job satisfaction. A survey was administered through an online database. The survey included questions regarding physical work
environment, the presence or absence of live interior plants, windows,
exterior green spaces, environmental preferences, job satisfaction, and
demographical information. About 600 office workers from Texas and
the Midwest responded to the on-line workplace environment survey.
Data were analyzed to compare levels of job satisfaction of employees
that worked in office spaces that included live interior plants or window
views of exterior green spaces and employees that worked in office
environments without live plants or window views. Demographic information collected allowed controlling for salary, occupational level,
educational level, age group, gender, and ethnicity. This research data
can be particularly useful in urban planning, commercial property
design and to encourage the incorporation of plants and green spaces
in interior and exterior development projects.
POSTERS–WEDNESDAY
Echinacea is becoming a well-established, high-value crop, both as an
ornamental and a dietary supplement. A comprehensive collection of
Echinacea germplasm is conserved by the USDA-ARS North Central
Regional Plant Introduction Station (NCRPIS) in Ames, Iowa, and is
available via seed distribution for research and educational purposes
(ars-grin.gov/npgs). Representing all nine species collected throughout
their respective North American geographic ranges, the Echinacea
collection includes 179 accessions. Extensive morphological characterization data associated with this collection have been compiled and
are available to researchers on the Germplasm Resources Information
Network (GRIN) database to aid in selection criteria. The collection
has been used extensively for various research projects, ranging from
ornamental breeding studies to HPLC analyses of metabolites of interest
to the phytopharmaceutical industry. This poster will summarize the Echinacea collection conserved at the NCRPIS, including a list of available
accessions by species, illustrations of seed, and control-pollinated cage
propagation methods; and facilities utilized for seed cleaning, testing,
and storage. In addition, instructions on how to use the GRIN database
to view evaluation data and acquire germplasm will be provided.
horticultural sales in the United States and 11% of the total value of U.S.
agricultural production. The majority of jobs available in the nursery
industry are labor intensive. In Ohio, 60% of the nursery workforce is
composed of Hispanic laborers. A survey conducted in 2000 targeting
Hispanic nursery workers in Oregon and Ohio revealed a great need for
basic technical information in their native language. In order to address
this issue in Ohio, a Spanish language nursery tour was developed in
2002 and offered annually thereafter. Conducted entirely in Spanish,
the tour focuses on basic technical information in the area of field and
container production. Tours take place at commercial nursery sites in
the Lake County region of Ohio. Demonstrations at the nurseries have
highlighted such practices as planting, pruning, and irrigation. Interest
in disseminating more technical information in Spanish to the Hispanic
workforce has developed as a result of these tours. In Jan. 2005, supervisors of Hispanic nursery workers were surveyed at the Central
Environmental Nursery Trade Show (“CENTS”) in Columbus, Ohio,
to determine the level of interest in technical education programs for
Hispanic employees (65%) and what programs were needed (Safety
16%, Pruning 14%, and English 13%). A multi-state survey in English
and Spanish will be conducted over the next two years (2005 and 2006).
The goal of this project is to better understand the backgrounds and
technical needs of the workers in seven states filling predominantly
manual labor positions, in order to help stabilize and engage the workforce through education.
(153) Delighted Consumers Buy Again
Jessica M. Hicks1, Bridget K. Behe1, Thomas J. Page2,
Jennifer H. Dennis*3, R. Thomas Fernandez1
1
Michigan State University, Horticulture, East Lansing, MI, 48824; 2Michigan State University, Marketing and Supply Chain Mgt., East Lansing, MI, 48824; 3Purdue University,
Horticulture and Ag Economics, West Lafayette, IN, 47907
Customers take some risk when they buy plants, and the emotions they
experience from that purchase are important indications of whether they
will return to buy again. Previous research by Dennis et al. showed
that regret, a negative emotion, caused consumer switching behavior
by their intentions to either buy an alternative product, purchase products from an alternative retailer, or switch out of gardening entirely.
What happens when things go right? Customer satisfaction has been
the metric businesses use to quantify success in customer retention. If
customers who regret the purchase switch, do happy customers return to
buy again? This research investigated the role of customer satisfaction,
delight (a positive emotion), and prior plant knowledge on repurchase
intentions. An Internet survey with 659 flowering plant purchasers
throughout the U.S. was conducted in Sept. 2004 to examine the initial
purchase and the actual performance of the plant following purchase.
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Data were analyzed using structural equation modeling with LISREL
software. Results showed that customer satisfaction level and delight
were not affected by prior plant knowledge. Satisfaction level did not
affect repurchase intentions, but customer delight did. Results were
consistent with existing literature, indicating that greater emphasis should
be placed on delighting consumers, rather than merely satisfying them.
(154) Investigating Consumer Demand for Fresh Market
Edamame in Metro-Philadelphia Supermarkets
Dru N. Montri*, Kathleen M. Kelley, Elsa S. Sánchez
The Pennsylvania State University, Dept. of Horticulture, University Park, PA, 16802
An in-store marketing study was conducted in Fall 2004 to determine
consumer demand for fresh, inshell edamame [Glycine max (L.) Merrill].
Each Wednesday from 1 Sept. to 6 Oct. 2004, thirty 12-ounce plastic
clamshells were placed in the produce department of four supermarkets in metro-Philadelphia, Pa. Packaged edamame remained in the
supermarkets for 1 week and was replaced with fresh product when the
next weekly delivery was made. A sample recipe, a follow-up survey
and an addressed, postage-paid reply envelope were attached to the
bottom of each clamshell. The survey was used to determine consumer
perceptions, interest in Pennsylvania-grown edamame and the criteria
they consider when choosing new produce items sold at supermarkets
for themselves and their families. Of the 480 clamshells that were delivered, 312 were purchased. The total number of clamshells purchased
weekly ranged from 64 to 87, while the number of clamshells purchased
weekly at individual stores ranged from 6 to 30. Thirty-three surveys
were returned with all participants responding that they had heard of
or were familiar with edamame prior to purchasing the container. Of
those who responded, 78.8% had purchased edamame before. Based
on the total number of packages sold, a potential demand for fresh,
inshell edamame exists among consumers in metro-Philadelphia. Results
from this study will be used to assist small-acreage growers interested
in marketing specialty vegetable crops, such as edamame, to chain
supermarkets. By understanding consumer interests, we are able to
more effectively determine which type of packaging and promotional
materials best attract the attention of potential buyers.
(155) New Opportunities for Asian Vegetables in Local
Markets
Kurt T. Range*1, S. Alan Walters1, Bradley H. Taylor1, Wanki Moon2
1
Southern Illinois University, Plant, Soil, and Agricultural Systems, Carbondale, IL, 629014415; 2Southern Illinois University, Agribusiness Economics
Consumers at two local direct produce markets in greater St. Louis,
Illinois, were surveyed to measure interest and buying habits for Asian
vegetables in 2003. A written survey instrument containing 20 questions
about use, attitudes, and purchasing behavior of Asian vegetables was
completed by 40 randomly selected shoppers at each market: a farmers
market and a roadside market. Although most respondents were not
familiar with Asian vegetables and 79% consumed less than 5 lbs of
the product annually, they expressed a strong interest to learn more
about these vegetables. Respondents reported typically purchasing
Asian vegetables at supermarkets (31%), restaurants (30%), and direct
markets (9%), while 30% did not normally purchase the product. Only
20% of the participants consumed Asian vegetables more than once per
month, while an additional 25% avoided these vegetables entirely. When
asked, “What would persuade you to purchase fresh Asian vegetables?”,
surprisingly 40% of respondents answered “access to recipes.” Our
results suggest local marketers can dramatically increase sales of Asian
vegetables with simple education/promotion efforts.
(156) New Entrepreneurial Approach: A Model for Asian
Herbal Products with Small Business Management
Strategies
Usha Palaniswamy*1, Zafar Bokhari2
1
University of Connecticut, Asian American Studies, Storrs, CT, 06268; 2Chicago State
University, Marketing
The important effect of dietary factors on health status has been recognized since antiquity. Since the discovery of the beneficial effects of
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dietary phytochemicals and bioactives, a new dimension of foods have
emerged in the market. These “functional foods” are being developed
by all major food companies and new ones are regularly brought into
the market. While developing new functional foods and nutraceuticals,
the association and identification of such foods and beverages with
traditional foods and medicinal preparations, and/or popular forms of
existing products are bound to bring long-standing consumer acceptance, which is an important desirable factor in sales and marketing.
Following this concept, Zafi Beverages, Inc., Chicago, is developing a new line of functional products (new herbal teas and energy
drinks). Zafi is also introducing a unique marketing and distribution
system to create a new team of entrepreneurs, providing an excellent
opportunity for growth in sales and marketing to new entrepreneurs.
It targets ethnic entrepreneurs by offering an opportunity to use their
networking abilities and be part of an exciting new partnership in
the new host country, as well as a strategic business plan. The ethnic
entrepreneurs are also constantly in contact with their consumers by
virtue of the existing ethnic allegiance and cohesion and are able to
identify the consumer needs and concerns directly. These small ethnic
entrepreneurial networks can be identified as distinct “micro-marketing
systems” within the national economy. The advertised market potential
for Zafi is summarized to include an offer of immediate cash flow, more
revenue and profits, marketing and financial education support, as well
as a promising new line of products.
(157) Analysis of Ornamental Horticulture Products and
Services in Iowa
Cynthia Haynes*, Ann Marie VanDerZanden, Jeffery Iles
Iowa State University, Department of Horticulture, Ames, IA, 50011
In 2004, the greenhouse and nursery industry was ranked as the fourth
largest crop group in the United States based on farm cash receipts
(USDA, 2004). The ornamental crop sector was expected to post total
sales in excess of 15.3 billion dollars in 2004 (USDA, 2004). Landscape
services within the green industry have risen from 28.9 billion in 2002 to
41.6 billion in 2004 (ALCA, 2004). In Iowa, recent surveys of turfgrass
and edible food crop production and services have shown a combined
net worth of more than 1 billion dollars. However, these surveys failed
to include nursery and garden centers, greenhouse growers, landscape
designers/contractors, arborists, and florists. Therefore, the objective
of this project was to better understand the scope and scale of the ornamental horticulture industry in Iowa. A questionnaire was developed
and mailed to 1293 horticulture businesses in Iowa. The survey instrument was developed with input from members of the Iowa Nursery
and Landscape Association Research Corporation. Before mailing, it
was reviewed by survey professionals and piloted to a select group of
green industry representatives and edited per their suggestions. Three
weeks after mailing, a reminder postcard was sent. Respondents were
sorted as to type and size of business, number of employees, and annual sales. The percentage of gross receipts was categorized by types
of plants sold and services provided. Respondents also were asked
about the factors that limit their success, their strengths compared to
competitors, and their expectations for future growth.
(158) Evaluating Grower, Retailer, and Consumer Interest
in Annual Planters
Jonathan D. Phillips, Kathleen M. Kelley*, E. Jay Holcomb
The Pennsylvania State University, Dept.of Horticulture, University Park, PA, 16802
Three intercept surveys were conducted at the Penn State Southeast
Research and Extension Center in Landisville, Pa., at three separate field
days during the period of 28 July 2004 to 4 Aug. 2004 to determine grower
(n = 78), retailer (n = 52), and consumer (n = 55) preference for annual
planters. Survey participants were self-selected and asked to answer
questions evaluating both their preference for and past experience with
purchasing annual planters, as well as sociographic and demographic
questions. Growers who were 45 years of age or younger were more
likely to take price into consideration when creating an annual planter
(68.8%) than those who were 46 years of age or older (43.3%), but less
likely to use point-of-purchase material to educate consumers on proper
container care (45.2% and 75.0%, respectively). Additionally, retailers
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whose business was 89% retail or less were less likely to consider price
when creating annual planters (53.3%) than those participants whose
business was 90% retail or greater (84.2%), and were also found to be
less likely to use point-of-purchase material to educate consumers on
proper container care (46.7% and 72.2%, respectively). Consumers
were more likely to consider price when purchasing an annual planter
if they were female (92.7%) than if they were male (66.7%). Consumer
participants who resided in single-family homes were more likely to
take the color combination into consideration when purchasing annual
planters (100.0%) than those who live in another form of housing (e.g.,
apartment or mobile home; 66.7%). Additionally, consumers who live
in single-adult households were less likely to consider color combination when purchasing an annual planter (88.9%) than those who live
in households with two or more adults (100.0%).
(159) The Impact of Interior Houseplants in University
Classrooms on Course Performance, Course Satisfaction,
and Student Perceptions of the Course and Instructor
Jennifer Doxey*, Tina M. Waliczek
Texas State University, Department of Agriculture, San Marcos, TX, 78666
Poster Session 41—Fruit and Nut Crops Nutrition
20 July 2005, 1:15–2:00 p.m.
Poster Hall–Ballroom E/F
(326) Foliar Applications of 6-BA, Potassium Phosphate,
and Calcium Chloride Affect Pear Fruit Quality
Xiaogang Li1, Ling Jin2, Jing Ling1, Zhongchun Jiang*3
1
Jiangsu Academy of Agriculture Science, Institute of Horticulture, Nanjing, Jiangsu,
210014, China; 2Dr. Sun Yatsen’s Mausoleum, The Administration Bureau, Nanjing,
Jiangsu, 210014, China; 3State Univ. of New York College of Ag and Tech, Department
of Plant Science, Cobleskill, NY, 12043
Foliar application of hormones and nutrients can improve fruit quality,
but specific conditions for applying hormones and nutrients may vary
among fruit species. The objective of this study was to determine the
effects of 6-BA, potassium phosphate (monobasic), and calcium chloride on fruit weight, palatability, and storage quality of 8-year-old pear
trees, cv. Hosui. Foliar applications of 1 mg·L-1 6-BA, 0.3% potassium
phosphate, 0.3% calcium chloride, or 0.3% potassium phosphate +
0.3% calcium chloride were made at 20-day intervals from June until
maturity. All foliar applications increased average fruit weight over
the control (distilled water). 6-BA or the combination of potassium
phosphate and calcium chloride increased fruit weight more than did
potassium phosphate or calcium chloride alone. Fruit palatability,
measured as the ratio of sugar content to acid content, was significantly
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(327) Correcting Ni Deficiency in Pecan and Other Crops
Bruce W. Wood*, Charles C. Reilly, Andrew P. Nyczepir
USDA-ARS, SE Fruit and Tree Nut Research Laboratory, Byron, GA, 31008
The discovery of nickel (Ni) deficiency in field plantings of pecan
[Carya illinoinensis (Wangenh.) K. Koch] (Wood et al., 2004) has led
to efforts to identify appropriate management approaches to correct
tree deficiency and to identify the causes for Ni deficiency. Evaluation of several inorganic and organic forms of Ni have indicated that
solutions from all sources function well to correct deficiencies when
timely applied as a foliar spray to affected trees at Ni concentrations
>10 mg·L-1. Addition of urea, ammonium nitrate, or nicotinic acid to
Ni spray solutions increased apparent foliar uptake from Ni sprays. The
lower critical level of Ni, based on foliar analysis, appears to be in the
3-5 mg·L-1 dw range, with the upper critical level appearing to be >50
mg·L-1 dw. The cause of Ni deficiency in soils possessing plenty of Ni
is associated with excessive amounts of one or more metals (e.g., Ca,
Mg, Fr, Mn, Cu, and Zn) that inhibit Ni uptake and/or utilization. Root
damage by nematode feeding and cool/dry soils during early spring also
contributes to Ni deficiency. Foliar application of Ni to foliage in the
autumn and subsequent appearance of Ni in dormant season shoot tissues
indicates that Ni can be mobilized from senescing foliage to dormant
season shoots and is therefore available for early spring growth. Evidence
indicates that pecan has a higher Ni requirement than most other crop
species because it transports nitrogenous substances as ureides. Thus,
there is evidence that Ni-metalloenzymes are playing either a direct
or indirect role in ureide and nitrogen metabolism. It is postulated that
crop species that are most likely to exhibit field level Ni deficiencies are
those that transport N as ureides. Candidate crops will be discussed.
(328) Effect of Supplemental Nitrogen Application at
Selected Times on Pecan
Michael Smith*
Oklahoma State University, Department of Horticulture and Landscape Architecture,
Stillwater, OK, 74078
POSTERS–WEDNESDAY
Many individuals and businesses enhance the central design of their
homes or offices with living interior plants. While the aesthetic values
of interior greenery are obvious, some research has suggested that interior living plants may offer some psychological and restorative values,
such as reduced tension, better coping mechanisms, and increased
concentration and attention. The main objective of this research was to
investigate the impact of plants within a university classroom setting
on course performance, course satisfaction, and student perceptions of
the instructor. The study was designed to include a minimum of two
classes of the same coursework, taught by the same professor in the
same room. Three sets of two classes each, and ≈500 students were
included within the study. Throughout the semester, the experimental
class of students was treated by including an assortment of tropical plants
within the classroom. Plants were not present in the control classroom
of the study. A survey administered to each classroom of students at
the end of the semester asked students to provide demographic data
including class rank, gender, and grade point average. The professor
for each course provided information on each student’s grade for the
course, as well as overall quantitative information on how well students were satisfied with the experience they had within the course.
The results demonstrate value added to the classroom experience and
help to justify consideration of the added expense of interior plants in
meeting the goals of instructor and curriculum.
lower in 6-BA, potassium phosphate, and calcium chloride treatments
than in the control. All treatments increased vitamin C content over the
control. Fruit storage quality in calcium chloride or calcium chloride
+ potassium phosphate treatments was superior to that in the control.
Potassium phosphate alone and 6-BA treatments had no effects on fruit
storage quality. We conclude that foliar applications of 0.3% potassium
phosphate + 0.3% calcium chloride or 1 mg·L-1 6-BA can increase
average fruit weight and improve fruit palatability.
Supplemental nitrogen applications were tested to reduce irregular
bearing and improve yield on drip-irrigated pecan (Carya illinoinensis
Wangenh. C. Koch. cv. Mohawk) trees planted in 1989. Treatments
were: 1) no N fertilization; 2) 75 kg·ha-1 N in March; 3) 75 kg·ha-1 N
in March plus 50 kg·ha-1 N in August; and 4) 75 kg·ha-1 N in March
plus 50 kg·ha-1 N in October. Withholding N did not reduce July leaf
N concentration compared to the other treatments until the sixth year
of the study. Trees receiving N had similar July leaf N concentrations regardless of treatment throughout the study. October leaf N
concentrations were unaffected by treatment, except in 2002, when
withholding N suppressed leaf N compared to other treatments. The
percentage of fruiting shoots was lower when supplemental N was applied in October compared to August during 2 of 6 years. Otherwise,
the percentage of fruiting shoots was unaffected by treatment. Weight
per nut and kernel percentage were not affected by treatment, except
kernel percentage was lower during 1 year when supplemental N was
applied in August compared to October. Kernel grade was usually not
affected by treatment.
(329) Postharvest Urea Foliar Sprays Affect Almond and
Prune Leaf Nitrogen and Sulfur Dynamics
Franz J.A. Niederholzer*1, R. Scott Johnson2
1
University of California, Cooperative Extension, Yuba City, CA, 95991; 2University of
California, Cooperative Extension, Kearney Ag Center, Parlier, CA, 93648
Urea foliar sprays may be a more efficient and environmentally sound
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alternative to soil applied fertilizer N in the postharvest period in tree
crop production in California. While tree crop sulfur (S) status can
interact with tree N status to affect growth, we know of no study assessing tree crop leaf N and S dynamics following fall (postharvest)
foliar urea applications. We conducted a field study to measure temporal
dynamics of leaf N and leaf S (% dry weight basis) following postharvest urea sprays on prune (Prunus domestica) and almond (Prunus
dulcis). June-budded nursery stock prune (‘French’ on Myro 29C) and
almond (‘Price’ on Lovell) trees were sprayed to dripping with 6.5%
(w/w) and 10% (w/w) standard urea solutions, respectively. Prunes were
sprayed on 1 Oct. 2003 and almonds on 18 Nov. 2003. Leaf samples
were taken over a 3-week (almond) or 8-week (prune) period, beginning just before treatment. Foliar urea sprays significantly increased
prune (23%) and almond (14%) leaf N compared to untreated control
within 8 days of application. This affect was transient, as there were
no differences in leaf N concentrations between treated and untreated
trees at final leaf sampling. Urea sprays did not affect almond leaf S
concentration relative to untreated trees. Prune leaf S was significantly
reduced compared to untreated trees 8 days after treatment, but only
on that sampling date. Remobilization of S from the leaves of control
trees of either species was not apparent.
(330) Growth and Nutritional Response of Six Citrus
Rootstocks to Increasing Levels of Copper
Joseph Albano*, Kim Bowman
USDA-ARS, U.S. Horticultural Research Laboratory, Horticulture & Breeding Research
Unit, Fort Pierce, FL, 34945
Nutrient disorders related to excessive levels of copper in soils are
common in Florida citrus groves that have been under production
for many years, mainly due to the continual use of copper-containing
pesticides. The objectives of the study were to investigate the growth
and nutritional response of six citrus rootstocks (nonbudded) grown
in 4-L containers in sand to increasing concentrations of copper. The
rootstocks included: Swingle citrumelo (Citrus paradisi Macf. × Poncirus trifoliata [L.] Raf.), Volkamer lemon (C. volkameriana Ten. and
Pasq.), Cleopatra mandarin (Citrus reticulata Blanco), Flying Dragon
(P. trifoliata); and two new USDA series rootstocks, US-812 (Sunki
mandarin × P. trifoliata released in 2001), and US-897 (a hybrid of
Cleopatra × Flying Dragon not yet released). Copper was supplied at
0.05, 0.25, 1.00, and 2.00 mg·L-1 CuEDTA incorporated into a modified
Hoagland’s nutrient solution. As a mean of all Cu treatments, whole
plant Cu levels (μg·g-1) were: Flying Dragon, 17.33; US-897, 21.68;
Cleopatra, 27.33; US-812, 28.84; Swingle, 29.74; and Volkamer, 34.05.
As a mean of all Cu treatments, foliar Cu levels (μg·g-1) were greatest
and least in US-812 (7.74) and Cleopatra (4.05), respectively; and root
Cu levels (μg·g-1) were greatest and least in Volkamer (61.08) and Flying Dragon (30.08), respectively.
(331) In Brazil, Preharvest Calcium Sprays Were Not
Always Needed to Improve Fruit Quality of ‘Gala’ Apples
1
2
1
Paulo Roberto Ernani* , Jaques Dias , Cassandro Vidal Amarante ,
Diorvania Ribieiro3
1
Santa Catarina State University, Soil Science, Av. Luis de Camões, 2090, Lages, SC, 88520000, Brazil; 2Grupo Schio, Agropecuaria Schio, BR 285 km 3 Bairro Gloria, Vacaria, RS,
95200-000, Brazil; 3Santa Catarina State University, Soil Science, Lages, SC, Brazil
Calcium sprays have improved quality and storage life of apples throughout the world as a result of Ca prevention of many fruit physiological
disorders. The efficacy of Ca sprays, however, varies according to soil,
cultivar/rootstock, orchard cultural practices, and weather conditions.
This study was carried out from 1998 to 2004 in southern Brazil in
order to assess the effect of Ca sprays on quality of ‘Gala’ fruits in
an orchard planted in 1988 on a density of 1234 trees/ha. Treatments
consisted of 0, 4, 8, and 12 sprays of 0.5% CaCl2. Fruits of same size
and maturity level were annually analyzed at harvest and after 5 months
of cold storage. In five out of six seasons, fruits from all treatments
were free of any physiological disorder, and Ca sprays had no effect on
leaf composition and on fruit quality attributes (soluble solids, acidity,
starch pattern index, flesh firmness, and concentrations of N, K, Ca,
and Mg). In the 2000–01 season, however, when yield was 18 t·ha-1 and
fruits had an average weight of 175 g, the incidence of bitter pit plus
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lenticel blotch pit on stored fruits decreased from 24% in the treatment
with no calcium to 2% in that with 12 calcium sprays. Two seasons
later, yield was also light (25 t·ha-1) and fruits were big in size (168 g),
but they did not show any disorders regardless of Ca sprays. It seems
that the incidence of Ca related disorders in ‘Gala’ apples grown on
limed soils in Brazil only occurs in seasons with a light crop load as
a result of large fruits and a high leaf/fruit ratio, associated with some
unknown climatic factor.
(332) Fabric Cover Effects on Soil Fertility and Plant
Nutrition of Sweet Cherry
Xinhua Yin*, Janet Turner, Clark Seavert, Roberto Nunez-Elisea,
Helen Cahn
Oregon State University, Mid-Columbia Agricultural Research and Extension Center,
Hood River, OR, 97031-9512
The influences of a synthetic fabric cover in the row area of sweet cherry
trees on soil fertility and plant nutrition are largely unknown. A field
trial has been conducted on young ‘Regina’ sweet cherry on a sandy
loam soil at the Mid-Columbia Agricultural Research and Extension
Center, Hood River, Ore., since 2001. The difference in soil NO3-, P,
K, Ca, Mg, S, B, Zn, Mn, Cu, pH, or organic matter was nonsignificant
between the covered and non-covered treatments in any year. Leaf N
content was 11% to 16% greater with the covered treatment compared
with the non-covered treatment in 2002 and 2003, but leaf N was
similar for the two treatments in 2001. Leaf P content was similar for
the two treatments in 2001, but was about 36% less with the covered
treatment than the non-covered treatment in 2002 and 2003. Leaf Ca
content was decreased by 11% to 17% due to a synthetic fabric cover
in 2002 and 2003. Leaf Mg content was 13% to 24% less with the
covered treatment than the non-covered treatment in 2002 and 2003.
However, the decreased leaf P, Ca, and Mg contents with the covered
trees were due to the dilute effects of increased tree growth. The effects of a fabric cover on leaf K, S, B, Zn, Mn, and Cu contents were
primarily nonsignificant. Our results suggest that although nutrient
availability in the soil is not reduced by a wide synthetic fabric cover,
higher rates of fertilizers may be needed for the covered sweet cherry
trees due to the elevated tree growth and fruit production from a longterm perspective.
Poster Session 42—Genetics and Germplasm 3
20 July 2005, 1:15–2:00 p.m.
Poster Hall–Ballroom E/F
(14) Hybrid Azalea (4X) × Rhododendron (2X)
‘Azaleodendron’ Progeny Have an Azalea Phenotype
Stephen L. Krebs*
The Holden Arboretum, Research, Kirtland, OH, 44094
Genus Rhododendron contains more than 800 species worldwide,
currently grouped into eight subgenera. Four of these subgenera—comprising the evergreen azaleas, deciduous azaleas, small scaly-leaved
rhododendrons, and large non-scaly leaved rhododendrons—have been
the focus of ornamental breeding for over 150 years. As a rule of thumb,
species within a subgenus are cross-fertile, and most hybrids are derived
from intra-subgeneric crosses. Success with wider (inter-subgeneric)
crosses, especially deciduous azaleas × large-leaved rhododendrons,
has been occasionally reported in the past, based on the intermediate
morphology of the hybrids. I crossed a tetraploid ‘Ilam group’ azalea
with R. ‘Catlalgla’ (a selection of the native diploid rhododendron
species R. catawbiense) and produced a small population of seedlings
that proved to be true ‘azaleodendron’ hybrids, based on shared parental alleles at 2 isozyme loci, Idh-1 and Mdh-3. However, none of the
progeny are hybrid in appearance; they share the leaf morphology and
deciduous trait of the maternal azalea parent. I attribute this result to
a dosage effect in these (probable) triploid hybrids, where the azalea
genetic contribution is twice that of the rhododendron parent. Higher
copy number can be inferred from stronger band intensities for the
azalea gene at diallelic loci (Idh-1), or from triallelic loci (Mdh-3)
where the genetic contribution to the hybrid progeny appears to be 2:1,
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azalea : rhododendron. Previously, azalea-like progeny from azalea
× rhododendron crosses were thought to result from parthenogenesis
or accidental self-pollination.
(15) Evaluation of Genetic Variation in Pawpaw
Cultivars using Simple Sequence Repeat Markers
Jeremiah D. Lowe*, Kirk W. Pomper
Kentucky State University, Horticulture, 146 Atwood Research Center, Frankfort, KY, 40601
(16) Fruit Quality of the USDA Opuntia sp. Germplasm
Collection
Maria M. Jenderek, Barbara Hellier*
USDA, ARS, National Arid Land Plant Genetic Resource Unit, Parlier, CA, 93648
The fruit of several Opuntia species (prickly pear) are a good source
of calcium, potassium, and ascorbic acid and are consumed fresh or
processed as juices or preserves. Plants of Opuntia may be grown in
arid and semiarid environments on marginal soils. Various cultivars,
particularly in the species Opuntia ficus-indica, are grown commercially
in the United States, Israel, Italy, Mexico, and South Africa. There is a
need for new sources of genetic diversity and subsequent germplasm
evaluation, and until recently, no publicly maintained germplasm collection of Opuntia existed in the United States. The purpose of this
study was to evaluate fruit quality of 25 Opuntia accessions, originating from six countries, and maintained at the USDA collection at the
National Arid Land Plant Genetic Resource Unit, Parlier, Calif. The
largest fruits were harvested from plants of accessions PARL 201, 202,
and 228 (227.6, 247.3, and 231.3 g/fruit, respectively). The hardest
peel was on fruits of PARL 225 and 234 (both 3.7 kg), and fruit pulp
of the same two accessions had the highest firmness (2.3 and 2.4 kg,
respectively). Soluble solids in mature fruit varied from 6.1% (PARL
231) to 15.0% (PARL 254). The fruit color ranged from light yellow
through orange, pink to dark purple. These characteristics and other
traits such as fruit acidity, presence of spines, and seed mass/fruit
indicated that the material represents a diverse germplasm collection,
usable for future cultivar development.
(17) TRAP Markers Help Categorize a Pelargonium
Collection
Rose Palumbo*1, Wai-Foong Hong1, Jinguo Hu2, Charles Krause3,
David Tay4, Guo-Liang Wang1
1
The Ohio State University, Plant Pathology; 2USDA-ARS Northern Crop Science Laboratory, Sunflower Research Unit; 3USDA-ARS, Application Technology Research Unit;
4
The Ohio State University, Ornamental Plant Germplasm Center
The Ornamental Plant Germplasm Center (OPGC) maintains a collection of herbaceous ornamental plants in order to protect future breeders
from a loss of genetic diversity. The current Pelargonium collection
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(18) Biodiversity of the Flavonoid Phlorizin in a Subset of
the USDA Apple Germplasm Core Collection
Todd C. Einhorn*1, Cecil Stushnoff1, Ann E. McSay1,
Phil L. Forsline2, Sam Cox3, Joel R.L. Ehrenkranz4,
Loretta Sandoval5
1
Colorado State University, Department of Horticulture and Landscape Architecture, Fort
Collins, CO, 80523; 2Cornell University, Department of Horticultural Sciences, Ithaca,
NY; 3USDA-ARS, High Plains Grasslands Research Station; 4Little Nell Laboratories,
Scientific Director; 5Colorado State University, Department of Food Science and Human Nutrition
Phlorizin is known for its role in reducing glucotoxicity and has a long
history of use in diabetes research. In addition, its contribution to the
pool of total phenolics adds to the overall health benefits attributed to
fruit. Phlorizin is limited to Rosaceae family plants, of which apple
comprises its current commercial source; however, limited information
exists regarding its biodiversity among apple taxa. A subset of 22 taxa
from a core collection of apple accessions representative of the global
genetic diversity of apple was used to investigate the biodiversity of
phlorizin present in apple shoots and in fruit relative to total phenolic
content and free radical scavenging capacity. Fruit and shoots were
harvested from the USDA Plant Genetic Resources Unit in Geneva,
N.Y. Validation and quantification of phlorizin was conducted using
a rigorous high-pressure liquid chromatography (HPLC) procedure.
Total phenolics in fruit, assayed using a Folin-Ciocalteu method and
expressed as gallic acid equivalents, ranged from 227 to 7181 mg·L-1
and were strongly related to 2,2’ azinobis (3-ethylbenzothiazoline6-sulfonic acid) (ABTS) antioxidant capacity for the core collection
(r = 0.778). On a molar basis, phlorizin had lower antioxidant capacity
than other major phenolic compounds present in apple fruit, but was
more effective than ascorbic acid. Phlorizin yield in dormant apple
shoots, expressed as percent weight, ranged from 0.9% to 5.5%. A
rapid, 96 well micro-plate spectrophotometric assay was also developed to aid in the screening of multiple samples for selection of
high phlorizin yielding apple taxa. Spectrophotometry overestimated
phlorizin content as expected, but the calibration curve between HPLC
and spectrophotometry was acceptable, r2 = 0.88.
POSTERS–WEDNESDAY
Pawpaw [Asimina triloba (L.) Dunal] is a tree fruit native to areas in
the Midwest and Southeast United States. Since 1994, Kentucky State
University (KSU) has served as the USDA National Clonal Germplasm
Repository, or gene bank, for pawpaw; therefore, the assessment of
genetic diversity in pawpaw is an important research priority for the
KSU program. There are over 1800 pawpaw accessions (trees) from
16 different states and over 40 cultivars that are planted on 8 acres at
the KSU farm. The objectives of this study were to develop microsatellite markers for pawpaw, and to then use those markers to evaluate 19
cultivars in the repository collection. Leaves of the pawpaw cultivar
Sunflower were sent to Genetic Information Systems (Chatsworth,
Calif.) for simple sequence repeat (SSR) primer and marker development. A total of 34 microsatellite primers were developed for pawpaw.
These primers were then used in a preliminary screening with five
pawpaw cultivars (‘Sunflower’, ‘Mitchell’, ‘Sweet Alice’, ‘Overleese’,
and ‘Prolific’). Results from this preliminary screening indicate that
four of the primers failed to amplify any product, 12 primers were
monomorphic, and 18 primers were polymorphic. Eleven additional
cultivars were then screened, which produced numerous polymorphic
products. For example, Primers B3 and B118 produced products ranging in size from 490 to 350 bp. Polymorphic products will be used to
examine genetic variation among the pawpaw cultivars screened.
includes ≈870 accessions. Our preliminary studies showed that TRAP
(Target Region Amplified Polymorphism) has promise for analyzing
the variation in our collection, and so we have expanded the study
to analyze the entire Pelargonium collection. We have used the same
primers for this screening of the Pelargonium collection as were used on
sunflowers, and TRAP results run on a sequencing gel showed 90–150
bands that segregate the population into groups of similar accessions.
In order to facilitate analysis of OPGC’s large population, we have
converted the method to a high throughput technique that efficiently
analyzed the entire population. We used a 96-well DNA extraction
kit from Qiagen that produced high quality DNA in spite of the high
phenol levels in some Pelargonium species. Also, the use of labeled
primers allowed analysis of the gels to be aided by a computer. These
results produce a categorization of the collection that, combined with
morphology and taxonomy, will form the basis for future studies that
will use target genes specific to Pelargonium.
(19) Cryopreservation of Arabidopsis thaliana Shoot Tips
Leigh E. Towill*, Gayle M. Volk
National Center for Genetic Resources Preservation, USDA-ARS, Fort Collins, CO, 80521
Arabidopsis thaliana shoot tips provide a model to study processes
important for cryopreservation. Cryopreservation was accomplished
using both vitrification and two-step cooling methods. With vitrification methods, shoot formation after liquid nitrogen (LN) exposure
was as high as 100% and 95% for shoot tips exposed to PVS2 at 0 °C
and to PVS3 at 23 °C, respectively. A two-step cooling method also
gave greater than 90% survival if shoot tips were cooled at 0.3 °C
per minute to below –30 °C before immersing the samples into LN.
The high levels of shoot formation after LN exposure in Arabidopsis
thaliana shoot tips will allow the use of mutants to examine how
alterations in biochemical, metabolic, and developmental processes
affect survival and growth.
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Poster Session 43—Viticulture
21 July 2005, 12:00–12:45 p.m. Poster Hall–Ballroom E/F
(377) Consumer Acceptance of Mayhaw (Crataegus opca
Hook. and Arn.) Fruit Juice Blended with Muscadine
(Vitis rotundifolia Michx.) Grape Juice
Alfred F. Trappey*1, Charles E. Johnson2
1
Louisiana State University, Food Science, Baton Rouge, LA, 70803; 2Louisiana State
University, Horticulture,
Growth in juice-based products is supported by an increasing consumer
base, which perceives fruit and fruit-based beverages as an integral
component of nutritious food types that can benefit health. New flavor
combinations, as well as added ingredients (i.e., vitamins) continue
to help boost juice appeal as a nutraceutical. New juice-based food
products such as blends, jellies, marinades, and pastry fillings could
benefit from the unique flavor attributes specific to mayhaw fruit juice.
Juice from one cultivar of muscadine grape (Vitis rotundifolia Michx.)
‘Carlos’ (bronze skinned) was mixed with varying levels of juice from
one cultivar of mayhaw (Crataegus opaca) ‘Texas Star’ (reddish-orange
skinned) fruit. Five different blend combinations were tested for both
individual juice quality and for juice-blend compatibility. A consumer
preference test was conducted (n = 75) on a 9-point hedonic scale for
color, taste, and overall liking. Next to the taste/flavor preference scores
for control (6.8), mayhaw juice used as the primary flavor ingredient in
blends was the second most preferred of all juices by the panelists. A
50/50 juice blend and 70/30 mayhaw/muscadine blend were the least
desirable of the five combinations tested. Juices from 60/40, 30/70,
and 40/60 mayhaw/muscadine were considered by the panelists as best
in flavor and overall acceptability. “Taste” had the strongest effect on
overall acceptability of juice from varying levels of mayhaw juice in
combination with muscadine grape juice. Panelists’ mean score averages
collectively were favorable of 60:40 and 50:50 juice blends and were
significant (P < 0.05) toward acceptance of a “mayhaw-muscadine”
fruit juice blended drink.
(378) Weed Management in Organic Grapes
Kathleen Delate*1, Andrea McKern1, Michelle Kirkland2
1
Iowa State University, Horticulture & Agronomy, Ames, IA, 50011; 2Kirkland Vineyards,
Norwalk, IA
Iowa was the sixth largest producer of grapes in the United States in
the early 1900s, with 24,000 ha under production. The rapid expansion
of petrochemicals post-World War II and grape’s sensitivity to 2,4-D
herbicides reduced vineyard size in Iowa to 28 ha in 2001. Recent
state governmental support for organic fruit research and viticulture
in general has led to the expansion of the grape and wine industry in
Iowa. As of 2001, 5883 ha of organic grapes were produced in the
United States. Challenges to organic grape production in the Midwest
include diseases and weeds. The cultivation of American grape cultivars
is essential in organic viticulture in the Midwest, including cultivars
that are relatively cold hardy and disease tolerant. From 2003 to 2004,
we experimented on-farm at Kirkland Vineyards, Norwalk, Iowa, with
methods of organically approved weed management. Three replications
of plots consisting of five vines each of ‘Marechal Foch’ were laid out
in 2003 in a completely randomized design in a 1-year-old vineyard.
Treatments consisted of wood chips, wood chips plus vinegar herbicide
(All-Down™, SummerSet Co., Chaska, Minn.), and mowing when
weeds and groundcover reached 15 cm. Wood chips decreased weed load
significantly over mowing alone, but wood chips plus vinegar herbicide
provided the most control over 2 years of the experiment. There was
a trend toward greater plant height in the wood chip treatment, but no
significant differences in plant height were observed among treatments.
(379) Ploidy Determination in Vitis rotundifolia using Flow
Cytometry
Xia Xu, Jiang Lu*, Zhongbo Ren
Florida A&M University, Center for Viticulture, Tallahassee, FL, 323177
Ploidy level in grapevines varies, especially since in vitro techniques
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are employed in the breeding process and after plants are treated with
either chemicals or radiation. Detection of ploidy level in grapevines
by microscopic chromosome counting is complicated by their high
number and the small size of chromosomes. Flow cytometry provides
an accurate and rapid method in determining the ploidy level in plant
tissue by measuring the nuclear DNA content in living cells and thus
is a very useful tool in plant breeding or genetic studies. The objective
of this research was to analyze the ploidy level of a selected group
of muscadine vines that were different from normal diploid vines in
morphology. These grapes were derived from either chemical treatment of known varieties or from controlled/open pollinations. Among
the 26 grapevines investigated, 8 were found to be diploids, 11 were
tetraploids, and 7 were chimeric aneuploids. Results of this study
indicate that flow cytometry is a quick, reliable tool for determining
ploidy levels of grapevines.
(380) The Effect of Kaolin Clay-based Particle Film
Applications and Canopy Manipulations on Fruit
Composition and Incidence of Cluster Damage due to
Sunburn in ‘Cabernet Sauvignon’ Grapevines
Rhonda J. Smith*
University of California, Cooperative Extension, Santa Rosa, CA, 95403
The effect of sunlight exposure on yield, fruit composition, amount
of damaged clusters, and berry temperature was evaluated in a terraced, hillside ‘Cabernet Sauvignon’ vineyard on the north coast of
California. Each terrace contained two vine rows identified as “inside”
and “outside” relative to the terrace surface. The standard canopy
management practice of removing lateral shoots from below the
clusters was imposed with three modifications (“umbrella”, “fogger”,
and “umbrella+fogger”) and an unmodified control. Applications of
a kaolin-based particle film were made to unmodified canopies and a
final treatment consisted of leaving lateral shoots. Canopies with umbrella modifications were not fully vertically shoot positioned. Fogger
emitters directed water into the cluster area when ambient temperature
reached 33.9 °C beginning in mid-July for a total of 16 fogger-events
through 8 Sept. 2004. Treatments were harvested 17 Sept. Yield was
affected by row type but not treatment, and inside and outside rows
produced an average of 2.1 and 3.4 kg/vine, respectively. Particle film
applications significantly reduced berry surface temperatures in the
afternoon of two measurement dates by 0.7 and 1.5 °C, respectively.
Applications did not significantly affect fruit maturity indices when
compared to fruit in the control; however, at the 7% probability level,
berry samples from vines that had been treated with kaolin-clay had
lower °Brix than samples from control vines. The mean range of
sunburn fruit across all treatments was 0.2 to 1.4 clusters per vine.
Umbrella and umbrella+fogger treatments significantly reduced the
number of damaged clusters (P < 0.05).
(381) Nutraceutical Profile of Selected Muscadine (Vitis
rotundifolia Michx.) Cultivars and Breeding Lines
Stephen J. Stringer1, Penelope Perkins-Veazie2,
Donna A. Marshall*1
1
USDA ARS, Small Fruit Research Station, Poplarville, MS, 39470; 2USDA ARS, South
Central Agricultural Research Laboratory, Lane, OK, 74555
The consumption of fresh fruit and vegetables has always been known
to provide essential nutrition to mankind and, both anecdotally and
clinically, has been linked to the prevention or alleviation of chronic
diseases. The muscadine grape, a fruit native to the southeastern U.S.,
contains numerous phenolic compounds that act as antioxidants and also
other compounds, such as resveratrol, that acts as a chemopreventative.
The concentrations of these compounds present in the muscadine grape
equal or exceed that known for any other small fruit. Fruit of selected
muscadine grape genotypes, including breeding lines and cultivars,
were evaluated over a 2-year period to assess the existing genetic
base for these nutraceutical compounds. Results demonstrated that
concentrations of total phenolics, ellagic acid, and resveratrol differ
significantly among cultivars and breeding lines. These results suggest
that it should be possible to breed for increased concentrations of the
health-promoting compounds in muscadine grapes.
HORTSCIENCE, VOL. 40(4), JULY 2005
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(382) Application of a Molecular Marker for Berry
Seed Size to Two Populations of Grapevines (Vitis sp.)
Developed in a Breeding Program
Frederick J. Ryan*, David W. Ramming
USDA ARS, Crop Diseases, Pest, and Genetics Research Unit, Parlier, CA, 936488
The development of grapevines with berries with small seed traces,
so-called seedless grapes, is a costly process. Marker assisted selection
would save time and money. Adam-Blondin et al. (Vitis 40:147. 2001)
demonstrated that a sequence characterized amplified region, SCC8,
could identify seedless grapevine cultivars in European accessions of
Vitis vinifera L. We have applied this marker to two populations of
grapevines in a breeding program in California. One population consisted of 100 individuals while the second had 109. The two crosses
had a common female parent, derived from ‘Flame Seedless’. Fruit
were evaluated over several seasons for parameters including total
weight of seeds or traces. DNA was isolated from leaves during the
spring. Amplification was carried out with SCC8 primers, followed
by digestion with Bgl II, and agarose gel electrophoresis. Individuals
were scored as homozygous SCC8+ (small seeded), heterozygous
SCC8+/scc8- (intermediate sized seeds), or homozygous scc8- (large
seeded) and mean total seed weight per berry was calculated for each
genetic class. In the first population, the number of individuals in
the inferred genotypes fit an expected 1:2:1 distribution (χ2 = 0.480,
P > 0.787) and seed weights for each genetic class were reasonable.
For the second population, it was necessary to postulate a null allele
in one parent, with a 1:1:1:1 expected distribution for genotypes
SCC8+/SCC8+, SCC8+/null, SCC8+/scc8-, and scc8-/null. The actual
distribution was in agreement with this model (χ2 = 4.379, P > 0.223).
The genotype SCC8+/null had the SCC8+ marker and total seed weight
>10 mg per berry. Large seeded individuals and heterozygotes could
be reliably identified with this marker.
(383) Effect of Harmony and Freedom Rootstocks on
Yield and Quality of ‘Red Globe’ Table Grapes
Manuel de Jesus Valenzuela-Ruiz1, Fabián Robles-Contreras2,
Raul Leonel Grijalva-Contreras*3, Rubén Macias-Duarte4
1
INIFAP-Caborca, Viticulture, Caborca, Sonora, 83600, México; 2INIFAP-Caborca,
Agroclimatology, 3INIFAP-Caborca, Protected Horticulture, 4INIFAP-Caborca, Soli &
Horticultural
(384) Raisin Production of ‘Fiesta Seedless’ on Freedom
Rootstock under Different Plantation Densities
Manuel de Jesus Valenzuela-Ruiz1,
Raul Leonel Grijalva-Contreras*2, Fabián Robles-Contreras3,
Rubén Macias-Duarte4
1
INIFAP-Caborca, Viticulture, Caborca, Sonora, 83600, México; 2INIFAP-Caborca,
Protected Horticulture; 3INIFAP-Caborca, Agroclimatology; 4INIFAP-Caborca, Soli &
Horticultural
Grape is one of the more important crops in northwestern Mexico
(Sonora), especially for table grape. Although raisin production is a
good option, it must be efficient and productive due to the problems of
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(385) Phenolic Analysis of Selected Grape Cultivars
Keri L. Andersen*1, Susan L. Cuppett2, Ellen T. Paparozzi1,
Paul E. Read1
1
University of Nebraska–Lincoln, Agronomy and Horticulture, Lincoln, NE, 685830724; 2University of Nebraska-Lincoln, Food Science and Technology, Lincoln, NE,
68583-0919;
Phenolic levels have been analyzed in several grape cultivars that are
suited for growing in southeastern Nebraska. The phenolic levels of
these cultivars are not known to have been previously published. The
polyphenol content of fruits and fruit products such as wine have been
shown to be directly correlated to the antioxidant potential of the product.
Antioxidants help to prevent the effects of aging and age-associated
diseases. The grape cultivars in the study are grown primarily for wine
production, but also as fresh table grapes and for making juice and jellies. The total phenolic content is being analyzed by the Folin-Ciocalteu
method. Of the red grapes, ‘St. Croix’ and ‘Frontenac’ have the highest
levels of polyphenols, followed by ‘Chambourcin’ and ‘deChaunac’,
with levels varying from 1.4–4.9 mg·g-1 (polyphenols/grape), measured
as gallic acid equivalents (GAE). The white grapes ‘Vignoles’ and
‘LaCrosse’ have total phenolic levels of 1.4 to 2.2 mg·g-1 (polyphenols/
grape), also measured as gallic acid equivalents (GAE).
(386) The Commercial Potential and Antioxidant
Characteristics of Unique Varietal Grape Juices
Joseph C. Scheerens1, Todd E. Steiner1, Artemio Z. Tulio, Jr.1,
Mustafa Ozgen*2, Diane D. Miller1, R. Neil Reese3,
A. Raymond Miller1, David C. Ferree1
1
Ohio State Univ., OARDC, Horticulture and Crop Science, Wooster, OH, 44691; 2GOP
Univ., Horticulture, Tasliciftlik, Tokat, 60240, Turkey; 3South Dakota State Univ., Department of Biology & Microbiology, Brookings, SD, 57007
Eight unique varietal grape juices were examined for their antioxidant
characteristics and commercial potential compared to that of commercial
‘Niagara’ and ‘Concord’. Grape juices were cold-pressed from mature
grapes, clarified, preserved, analyzed for pH, soluble solid and titratable acidity levels, pasteurized at 73 °C for 12 seconds, and sampled
for microbial testing. A preliminary panel of 41 routine evaluators
assessed all juices for 18 quality characteristics against known and
blind controls. Based on these results, ‘Reliance’, ‘Traminette’, and
New York 73 juices were presented to a 107-member panel of untrained
judges. Panelists rated experimental juices against commercial controls
for color, appearance, aroma and flavor intensity, sweetness, tartness,
overall quality, and preference. Among juices tested, ‘Reliance’ and
NY 73 offer the greatest potential as specialty grape juices. ‘Traminette’,
‘Chardonel’, ‘Chambourcin’, and NY 62 may also have potential as
grape juice cultivars, if processed to improve their color and clarity.
Small juice lots were hand-pressed from mature grapes and examined
for total anthocyanin and phenolic content, antioxidant characteristics
(DPPH and FRAP) and levels of individual phenolic compounds via
GC-MS. Total anthocyanin and phenolic contents of experimental juices
varied from 0–1460 μg·gfw-1 and 1001–2850 μg·gfw-1, respectively,
and were highest in NY 73. Estimates of antioxidant activity differed
POSTERS–THURSDAY
The region of Caborca, Sonora, Mexico, is one of the main area producers of table grapes, in particular the cultivar Red Globe. However,
the main problems in the region include shortage and high cost of
water, nematode infestation, and salinity. The objective of the present
research was to determine the behavior of ‘Red Globe’ cultivated on
the rootstocks Harmony and Freedom. This study was carried out in
the INIFAP Caborca research station in the year 2002, and consisted
of 10 plants for treatment (on each rootstock). When water was low, a
drip irrigation system was used. There was a completely randomized
statistical design. We observed no differences among the two rootstocks
in the different phonological stages (budbreak, flowering, and harvest
time). The results indicated statistical differences between the rootstocks.
Yield was higher on Freedom rootstock, with 2120 boxes/ha (boxes of
10 kg), an average of 470 boxes/ha more than on Harmony rootstock.
Freedom rootstock also improved the quality of the grape (better color,
bigger size of berry, and clusters, and the foliage was also more developed
with this rootstock). In both rootstocks, nematode control was 100%,
30% in water consumption, and no fertilizer was used.
shortage and high cost of water, salinity, and nematodes. The objective
of this research was the evaluation of ‘Fiesta Seedless’ on Freedom
rootstock for raisin production with different plantation densities. This
study was carried out in the INIFAP Caborca research station in 2002.
Four plant separations (1.0, 1.5, 1.7, and 2.0 m) were evaluated on
furrows 4 m apart. Plants were grafted on Freedom rootstock in 1999.
We also considered a control treatment (4 × 2 m on its own feet) and
fertilized it with 80N–60P–80K. All experiments were carried out
under the espalier training system with double crossbeam; watering
was under a drip-irrigation system; and the statistical design was
completely randomized. Statistical differences between the evaluated
spacings were not observed, but all densities surpassed the control.
Greatest yields were obtained with 1.5- and 1.7-m spacings, at 6.1
and 6.0 t·ha-1 of raisin, respectively, which were 2.2 t·ha-1 more than
the control (3.8 t·ha-1). There were no differences in sugar content and
harvest time, since all treatmens, including the control, were harvested
at 24 °Brix. Freedom rootstock had 100% nematode control, 30% less
water consumption, and was not fertilized.
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slightly among tests, but activity appeared highest in ‘Chambourcin’
and NY 73 and lowest in ‘Reliance’. Levels of individual compounds
varied substantially among juices.
(387) Evaluating the Resistance against Anthracnose by
Bioassay using Culture Filtrates from Elsinoe ampelina
Hae Keun Yun*, Kyo Sun Park, Jeong Ho Rho, Hyeon Mo Jo
National Horticultural Research Institute, RDA, Fruit Research Department, 475 Imockdong, Suwon, Kyunggi, 440-706, Republic of Korea
Breeding of cultivars resistant to anthracnose is one of the most
important grape-breeding goals in Korea. Culture filtrates produced
by E. ampelina were used to determine varietal susceptibility to anthracnose in grape cultivars as a substitute for pathogen inoculation
or field screening in this study. Resistance evaluated by bioassay of
grape leaves with culture filtrates and their ethyl acetate extracts was
compared with ones from pathogen inoculation and field screening.
To evaluate the resistance to anthracnose disease in grape germplasm,
European grapes, American grapes, and Vitis hybrids were tested.
Bioassay with culture filtrates produced by the pathogen showed that
‘Black Eye’, ‘Mario’, ‘Niunai’, ‘Rizamat’, and ‘Rosario Bianco’ were
sensitive; and ‘Campbell Early’, ‘Niagara’, and ‘Honey Red’ were
tolerant to anthracnose. In the result of anthracnose resistance evaluation by pathogen inoculation, some cultivars, such as ‘Black Swan’,
’Rizamat’, ‘Rosario Bianco’, and ‘Kaiji’, were susceptible; and others,
such as ‘Campbell Early’, ‘Niagara’, ‘Sheridan’, and ‘Izumo Queen’,
were found to be resistant to anthracnose. Evaluation in the vineyard
showed that ‘Black Eye’, ‘Mario’, ‘Niunai’, ‘Rizamat’, and ‘Rosario
Bianco’ were susceptible; ‘Campbell Early’, ‘Niagara’, and ‘Honey
Red’ were resistant. The results of bioassay with culture filtrates of
the pathogen were consistent with ones from the results by pathogen
inoculation and screening in the vineyard.
Poster Session 44—Organic Production
21 July 2005, 12:00–12:45 p.m. Poster Hall–Ballroom E/F
(408) Effects of Essential Oils on CO2 Assimilation,
Stomatal Conductance, and Evapotranspiration of Apple
Jason McAfee*, Curt Rom
University of Arkansas, Horticulture, Fayetteville, AK 72701
Pesticides and alternative fruit thinners are needed for certified organic
fruit growers. Transient reductions in photosynthesis (Pn) have proven
an effective technique for fruit thinning. Pesticides can be detrimental
to plant growth by Pn reduction. This study was developed to measure
plant response to foliar applications of essential oils at 2% concentrations. Treatments were applied to vegetative apple trees grown under
controlled environment conditions to study photosynthetic effects.
There was no significant effect on Pn for treatments; however, clove
oil was very phytotoxic and defoliated all trees in this study. Cinnamon
oil and cedarwood oil significantly decreased evapotranspiration and
stomotal conductance 1 day after treatment. Differences in plant growth
were not significantly different for all treatments excluding clove oil.
Studies on concentration effects may determine horticultural usefulness
of these compounds.
(409) The Impact of Tarnished Plant Bug Damage
on Antioxidant Characteristics of Organically and
Conventionally Grown Strawberries
Mustafa Ozgen*1, Joseph Kovach2, Lauren D. Harper2,
Simeon Wright3, Joseph C. Scheerens1
1
Ohio State Univ., OARDC, Horticulture and Crop Science, Wooster, OH, 44691; 2Ohio
State Univ., OARDC, Integrated Pest Management Prog.; 3Univ. of Missouri, Plant Diagnostic Lab, Columbia, MO, 65211
Six strawberry cultivars (‘Earliglow’, ‘Honeoye’, ‘Idea’, ‘Jewel’,
‘Northeaster’, and ‘Seneca’) were grown organically on three different
composts (yard waste, dairy barn waste, and vermicompost). Organic
treatments were contrasted against a synthetic fertilizer standard, a
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conventional pesticide standard and an untreated control. Plots were
rated for tarnished plant bug (Lygus lineolaris) damage during the
growing season. At harvest, berries were examined for their ascorbic
acid levels and total anthocyanin and phenolic contents. Ascorbic acid
content of berries in different cultivars and treatments were similar. As
expected, fruit anthocyanin and phenolic contents were significantly
different among the cultivars, and ranged between 160–230 μg·gfw-1
and 1039–1333 μg·gfw-1, respectively. Among treatments, anthocyanin
contents of strawberries were not significantly different, but berries
grown on the conventional pesticide standard had 8% to 12% lower
total phenolic content than the other treatments. In organic treatments,
production of phenolic compounds may have been induced in response
to increased tarnished plant bug feeding. This putative biotic stress
defense mechanism was seen most dramatically on tarnished plant bugsusceptible cultivars. However, as differences in phenolic levels were
greater among cultivars than among treatments, cultivar choice may
be a more important consideration than growing system for optimizing
antioxidant levels in commercially available fruit.
(410) Soil and Tissue Nitrogen and Fall Cabbage Yield
Associated with Varying Rates of Nitrogen Applied as
Different Organic Sources
Mark Gaskell*, Rachel Grande
University of California, Cooperative Extension, Santa Maria, CA, 93455
Fertilization is the most expensive cultural practice for increasing numbers of organic vegetable growers in California. Nitrogen (N) is the most
important and costly nutrient to manage and cost-effective N management practices are needed for efficient organic vegetable production.
Compost and green manure cover crops are widely used, economical
sources of N for organic vegetable production, but the pattern of release
from these pre-plant incorporated N sources may not adequately match
crop need for N. Additional application of an organic N fertilizer material
is needed to provide adequate N to long-season vegetable crops. Seven
types of organic fertilizers–feather meal (13% N), blood meal (14%
N), liquid fish waste (6% N), a micronized liquid feather meal (4%
N), a micronized feather/blood meal (13% N) for injection as a liquid
suspension, and the two micronized materials with an added microbial
inoculant—were each applied to fall cabbage at N rates of 0, 90, 180
lb/acre. Weekly residual soil nitrate N (SNN) was proportional to applied
N rate much of the season and varied from 5 to over 70 ppm. Marketable yield ranged from 8000 to 33,300 lb/acre. The SNN was highest
in plots receiving the liquid fish waste most weeks, and marketable
cabbage yield was also highest following application of N as liquid fish
waste at 180 lb/acre. A positive marketable yield response to increasing
rates of applied N was also observed for the other organic N materials.
(411) Companion Choice, Crop Density, and Mixture
Ratio Affect Polyculture Yield Advantage
Michael K. Bomford*
Kentucky State University, Community Research Service, Atwood Research Facility,
Frankfort, KY, 40601
Polycultures are thought to offer yield advantages over monocultures
when net competition between plants of different species is less than
that between plants of the same species. Planting density and crop ratios may both alter these competitive effects. To observe such effects,
dicultures of basil (Ocimum basilicum L.), brussels sprout (Brassica
oleracea L.), and tomato (Lycopersicum esculentum Mill.) were grown
organically at a range of ratios and densities (1–47 plants/m2) over two
field seasons. Relative land output (RLO) values were calculated from
field data and from modeled yield-density-ratio surfaces. Both methods
showed yield advantages from polyculture at high planting densities
(RLO = 2.20 @ top density), but not at low densities. Dicultures offered a 19% yield advantage, on average. Competition for resources
was compared by measuring canopy light interception and soil moisture
content, showing tomato to be the most competitive crop, followed by
brussels sprout, then basil. Diculture yield advantages were most pronounced when individuals of a less competitive species outnumbered
those of a more competitive species. Yield advantages were 36% and
20% for dicultures dominated by basil and brussels sprout, respectively.
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Dicultures dominated by tomato offered no yield advantage. The results
are discussed in terms of the current ecological understanding of plant
interactions, and possible advantages to be derived from small-scale
intercropping, popularly termed companion planting.
(412) Tomato Diseases
Donald Krizek*1, Patricia Millner1, Mary Camp2, David Clark1,
Mark Davis1, Bryan Butler3, John Teasdale1, Deborah Fravel4,
Sara Reynolds1, Ruth Mangum1, Ted Currier5
1
USDA-ARS, SASL, BARC-W, Beltsville, MD, 20705; 2USDA-ARS, Biometrical
Consulting Service, BARC-W, Beltsville, MD, 20705; 3University of Maryland, MD
Cooperative Extension Service, Carroll Co., Westminster, MD, 21157; 4USDA-ARS,
Vegetable Lab, BARC-W, Beltsville, MD, 20705; 5USDA-ARS, FMOD, BARC-W,
Beltsville, MD, 20705
A field study of organic production of tomato (Lycopersicon esculentum
Mill.) in high-tunnels was conducted in 2004. ‘Mountain Fresh’ was
transplanted 31 Mar.; ‘Ultra Sweet’ and ‘Sun Leaper’ were transplanted
on 21 July. The primary objective was to determine the feasibility of
obtaining two crops of fresh-market tomatoes by starting plants 4–8
weeks earlier than the average last spring-killing frost, and extending
the growing season 4–6 weeks past the average first fall-killing frost.
Plants were started at weekly intervals for 4 weeks in both seasons. Data
and observations were recorded on the yield of marketable fruits, plant
growth and development, and plant health. Other objectives were to
evaluate: 1) the benefits of using a selective UV-blocking film on plant
growth and development, disease events; and 2) compost amendments
on soil improvement and disease control. Major cultural challenges
included water management, soil texture/drainage, prevention of chilling injury, plant support, and adequate ventilation. Major disease/pest
challenges involved stalk rot caused by Sclerotinia sclerotiorum in
the spring, powdery mildew in spring and late summer, Alternaria and
Septoria leaf blight in late summer, and aphids, tomato hornworm, corn
earworm, and beet army worm also in late summer. In addition, macrofaunal intrusions by fox, mice, and birds occurred sporadically. Poor
drainage and stalk rot in the spring necessitated relocating the tunnels
to an uninfested site with better drainage. The fall crop yielded high
numbers of marketable quality fruits, well beyond the 15 Oct. average
killing frost date. The results suggest that with improved management,
there is a considerable potential for profitable extended-season production of organic tomatoes in this region.
(413) Evaluating Tomato Production during the First Year
of Organic Transitioning in High Tunnels
Adam Montri*, William J. Lamont, Jr., Michael D. Orzolek
High tunnels offer growers in temperate regions the ability to extend
the production season. Past research has shown that these low-input
structures also reduce disease and pest pressure. These characteristics
make high tunnels extremely attractive to organic growers. Tomatoes
(Lycopersicon esculentum Mill.) are the crop most often produced in high
tunnels in Pennsylvania and many producers are interested in combining both high tunnel and organic production methods. Growers may be
hesitant to transition to organic production due to conceptions concerning
reduced yields specifically during the 3-year transition period to USDA
certified organic status. A field trial investigating tomato production in
high tunnels during the first year of organic transitioning was conducted
in 2004 at The Penn State Center for Plasticulture, Russell E. Larson
Agricultural Research Center, Rock Springs, Pa. The objective of this
research was to evaluate yield of the four cultivars Big Beef, Mountain
Fresh, Plum Crimson, and Pink Beauty in an organic system relative to
a scheduled fertilization/irrigation regime and a fertilization/irrigation
regime employed using T-Systems International’s Integrated Agronomic
Technology. Data collected included total weight, total fruit number,
weight by grade, fruit number by grade, total marketable yield, and
fertilizer and water usage. Yield across cultivars ranged from 4.96
kg/plant to 6.83 kg/plant. ‘Pink Beauty’ exhibited the lowest yields in
both treatments, while ‘Plum Crimson’ and ‘Mountain Fresh’ exhibited
the highest yields in the IAT and scheduled treatments, respectively.
This experiment will be repeated in 2005 to further evaluate the performance of these cultivars.
HORTSCIENCE, VOL. 40(4), JULY 2005
final6_20July HS.indb 1071
Martha Maletta*1, Melvin Henninger2, Kristian Holmstrom3
1
Rutgers Cooperative Research and Extension and the New Jersey Agricultural Experiment
Station, Hunterdon County, Flemington, NJ, 08822; 2Rutgers Cooperative Research and
Extension and the New Jersey Agricultural Experiment Station, Plant Biology and Pathology, New Brunswick, NJ, 08901-8520; 3Rutgers Cooperative Research and Extension and
the New Jersey Agricultural Experiment Station, Pest Management, Vegetable IPM, New
Brunswick, NJ, 08901-8524
Potato leafhopper (PLH) control and plastic mulch culture for certified organic potato production were evaluated in 2003 and 2004. The
trials were conducted on the Rutgers Snyder Research and Extension
Farm’s certified organic fields. Production practices conformed to the
National Organic Program. The potato cultivar grown was ‘Superior’.
In 2003, PLH controls were: untreated control (UTC); Surround WP,
25 lb/acre; PyGanic EC 1.4, 1 pt/acre; Surround plus PyGanic; and
silver plastic mulch. PyGanic and Surround/PyGanic treatment reduced
PLH nymph counts and damage (hopperburn–HB), when compared
to the UTC. Counts were higher and HB more severe in silver mulch
plots than in the UTC, but marketable yield was more than double
the UTC. PyGanic and Surround/PyGanic treatment yields were 50%
higher than the UTC. In 2004, PLH controls were: PyGanic EC 1.4,
1–2 pt/acre; Diatect V, 2–4 lb/acre; and Surround WP, 25 lb/acre. The
crop was grown on bare ground or silver plastic mulch. Nymph counts
and HB were lowest on PyGanic- and Diatect-treated plots. Nymph
counts and HB for UTC and Surround treatment were higher on plastic
mulch than bare ground plots. Marketable yield was highest from PyGanic-treated plots. PyGanic or Diatect treatment yields were higher
from plastic mulched than from bare ground plots. The PLH control
and plastic mulch culture significantly increased organic potato yields.
Marketable yield from the UTC was lower than the New Jersey average
for conventional potato (275 hundred wt/acre) by 71% on bare ground
and by 39% with plastic mulch in 2003; 59% on bare ground; and 52%
with plastic mulch in 2004. PLH control with PyGanic combined with
plastic mulch culture resulted in yields just 7% less than the state average; yield on bare ground was 26% less.
(415) Evaluation of Weed Control Practices in an Organic
Bell Pepper Production System
Derek M. Law*, Brent Rowell
University of Kentucky, Horticulture, Lexington, KY, 40546
A 2-year field study in Lexington, Ky., evaluated the use of mulches in
two organic production systems for bell peppers. Two planting strategies, flat ground and plastic-covered raised beds, and five weed control
practices, straw mulch, compost mulch, wood chip mulch, corn gluten,
and “living mulch” clover were tested. In 2003, the mulches were applied at planting, while in 2004, shallow soil cultivation was used for
6 weeks prior to mulch application. In 2003, the experimental field
had been under a winter wheat cover crop; in 2004, the field had been
cover cropped for more than a year prior to planting with sudex/cowpea
(Summer 2003) and rye/hairy vetch (Winter/Spring 2004). Bell pepper
yields in both bed treatments were very low in 2003 due to extensive
weed competition. In 2004, plastic-covered raised beds coupled with
mulching in-between beds resulted in significantly higher yields than
the peppers grown on flat ground. These yields were as high as yields
from a conventional pepper trial conducted on the same farm. Compost
mulch, continuous cultivation, and wood chip mulch provided excellent
weed control in 2004. Straw mulch was variable in its weed control
efficacy; corn gluten and “living mulch” clover were ineffective.
POSTERS–THURSDAY
The Pennsylvania State University, Department of Horticulture, University Park, PA, 16802
(414) Evaluation of Potato Leafhopper Control and
Plastic Mulch Culture for Organic Potato Production
(416) Weed Management in Organic Sweet Corn
Anthony Silvernail*
Kentucky State University, Community Research Service, Frankfort, KY, 40601
Organic weed control in direct seeded vegetables depends on management strategies that control weed germination or growth which depletes
the weed seedbank. In 2004, a randomized complete-block experiment
conducted on land transitioning to organic production examined the
effects of tillage and control treatments on weed pressure in sweet corn
[Zea mays (L.) cv. SilverQueen]. The two tillage treatments consisted of
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6/20/05 5:02:28 PM
conventional (moldboard and rototill) and spader tillage. Weed control
treatments included a weed free control, a spring-tine weeder, rolling
cultivator, row flamer, stale seedbed, and corn gluten meal. In August,
the weed infestation was primarily goose grass [Eleusine indica (L.)
Gaertn.], crab grass [Digitaria sanguinalis (L.) Scop.], giant foxtail
(Setaria faberi Herrm.), and smooth pigweed [Amaranthus hybridus
(L.)] species. Dried weed weights indicated that smooth pigweed
constituted about 80% of the total weed biomass in all but the control
and flamer treatments. Plots managed with the spring-tine weeder or
corn gluten had twice the weed biomass of those managed with the
rolling cultivator and flamer. The rolling cultivator and control treatments produced equivalent husked corn yields (6.9 t·ha-1); yields were
reduced by the other weed control methods. At 5.4 t·ha-1, yields in the
flamer treatment were the lowest among all weed control methods.
The flamer suppressed both weeds and the crop, which may preclude
its utility for sweet corn production. Results demonstrated that the
rolling cultivator provided the best weed control without negatively
affecting potential yields.
conducted in-state focus group meetings through which barriers to
production and marketing, and opportunities for organic fruit in the
region were identified. Prioritized research and outreach needs that
were identified in the focus groups included use and understanding
of organic fertilizers and nutrient management; methods, knowledge
and awareness of pest disease and weed control including orchard
floor management; information on transition to organic; consumer
awareness and market development and the economics of organics.
The planning activities of the SROFWG support the development and
submission of grants for cooperative and collaborative research and
outreach programs to sustain and expand organic fruit production in
the southern region.
(417) The Chilean Organic Wine Industry
Since the passage of the Organic Foods Production Act in 1990, certified organic produce has begun to make a large impact on national
markets. However, USDA statistics indicate that many states in the
southern region have considerably reduced certified organic acreage
when compared to other regions in the United States. The absence of
organic acreage may perhaps originate with a lack of training and educational materials provided to producers due to unanticipated growth
of organic markets. A thorough review of all Arkansas Cooperative
Extension Service (ACES) materials, such as bulletins, publications,
and workshops over the past 10 years, would reveal what information
has been provided to producers on certified organic production. This
review of ACES materials defines the existing groundwork on which
ACES could construct future organic publications and outreach programs
in order to sustain and stimulate organic farming within the state.
Jorge O’Ryan1, Monica Ozores-Hampton*2
1
Universidad de las Americas, Horticulture, Santiago, Chile; 2University of Florida/SWFREC, Horticulture, Immokalee, FL, 34143-9515
The Chilean organic wine industry has comparative advantages with
Europe and the United States because of its ideal environmental
conditions, resulting in low presence of pests and diseases and lower
production cost. Additionally, the wine production process is one of
the strictest in the world, so the transformation from conventional to
organic wine production can be achieved economically. A survey was
conducted of 32 Chilean organic vineyards during 2004. The survey
included 18 questions about total surface area, certification, varieties,
final market, etc. The survey covered 95% of the land under organic
wine production, with a total of 1892 ha, of which 1088 ha have organic
certification and 804 ha are in transition to organic production. The
major vineyards and valleys with organic wine production are Maipo
(33.7%), Colchagua (17.2%), El Maule (14.0%), Curicó (9.9%), and
Cachapoal (8.8%). The most important organic red varieties currently
under production are ‘Cabernet Sauvignon’ (40.9%), ‘Merlot’ (15.1%),
‘Syrah’ (9.1%), ‘Carmenere’ (7.3%), ‘Malbec’ (3.3%), and ‘Pinot Noir’
(2.5%). The white varieties are ‘Sauvignon Blanc’ (6.4%), ‘Chardonnay’ (5.1%), and ‘Semillón’ (1.0%). The potential for the organic wine
industry in Chile is tremendous since organic vineyards represent only
2% of the total vineyard industry.
(418) The Development of a Southern Region Organic
Fruit Initiative
Heather Friedrich*1, Curt Rom,1 Jennie Popp2, Barbara Bellows3,
Donn Johnson4, Dan Horton5, Kirk Pomper6, David Lockwood7,
Steve McArtney8, Geoffrey Zehnder9
1
University of Arkansas, Horticulture, Fayetteville, AR, 72701; 2University of Arkansas, Agriculture Economics, Fayetteville, AR, 72701; 3National Center for Appropriate Technology,
Horticulture, Fayetteville, AR, 72702; 4University of Arkansas, Entomology, Fayetteville,
AR, 72701; 5University of Georgia, Entomology, Athens, GA, 30602; 6Kentucky State
University, Horticulture, Frankfurt, KY, 40601; 7University of Tennessee, Plant Sciences,
Knoxville, TN, 37996; 8North Carolina State University, Mountain Horticultural Crops
Research and Extension Center, Fletcher, NC, 28732; 9Clemson University, Entomology,
Clemson, SC, 29634
Southern organic fruit production is limited by a lack of regionally appropriate, scale-neutral, and market-focused research and technology.
There has been limited research, outreach, and cooperation among
universities on organic fruit crops in the southern region. Organic
research and outreach activities, based on producer input, must be
focused on the most limiting areas of the organic system in order to
allow southern producers to receive the economic and environmental
benefits that organic agriculture can provide. With funding from USDASARE and USDA-SRIPMC, researchers at the University of Arkansas
have collaborated with scientists, extension specialists, growers, and
representatives of the organic industry in Arkansas, Georgia, Kentucky,
North Carolina, South Carolina, and Tennessee to create a Southern
Region Organic Fruit Working Group (SROFWG). The SROFWG
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final6_20July HS.indb 1072
(419) The Relation of Cooperative Extension Programs,
Materials, and Publications for Organic Farming Systems
as Relates to Production
Kristen Harper*, Curt R. Rom
University of Arkansas, Horticulture, Fayetteville, AR, 72701
Poster Session 45—Vegetable Nutrition
21 July 2005, 12:00–12:45 p.m. Poster Hall–Ballroom E/F
(215) From Recommendation to Implementation:
Involving Vegetable Growers in Best Management
Practices
Eric Simonne, David Studstill, Robert Hochmuth, Justin Jones,
Cynthia Stewart*
University of Florida, Horticultural Sciences, Gainesville, FL, 32611
The Federal Clear Water Act and Florida legislation have mandated
the clean-up of impaired water bodies. The BMP manual for vegetable
crops lists the cultural practices that could maintain productivity
while minimizing environmental impact. BMPs focus on increased
fertilizer and irrigation efficiency, but growers must be involved in
the demonstration and adoption process if this voluntary program
is to be successful. Three commercial vegetable fields from farms
recognized as leaders in fertilizer and irrigation management were
selected to demonstrate how irrigation and fertilizer management are
linked together and how management may prevent water movement
below the root zone of melons grown with plasticulture. In Spring
2004, dye (Brilliant blue FCF) was injected into the irrigation water
three times during the growing season and soil profiles were dug to
determine the depth of dye movement. Similar results were found at
all three locations as the dye moved below at an average rate of 1.9
to 3.6 cm per day. Water movement was greater early in the season as
irrigation was applied for transplant establishment. These results suggest that some leaching is likely to occur on light-textured soils, even
when sophisticated irrigation and fertilization practices are followed.
Based on these observations, cooperators spontaneously proposed to
use two drip tapes, reduce preplant fertilizer, use a 100% injected N/K
program, and/or add organic matter to the soil as attempts to slow water
movement below the root zone of their crops. This project shows that
growers are more likely to try and adopt sustainable practices when
HORTSCIENCE, VOL. 40(4), JULY 2005
6/20/05 5:02:29 PM
they actively participate in the educational process than when production changes are mandated through legislation.
(216) Effect of Supplemental Potassium on Yield and
Quality of Processing Tomato
Christopher C. Gunter*1, David Francis2
1
Purdue University, Horticulture and Landscape Architecture, Southwest Purdue Ag.
Program, Vincennes, IN, 47591; 2The Ohio State University, Horticulture and Crop Science, Ohio Ag. Research and Development Center, Wooster, OH, 44691
Physiological disorders affect both the appearance and nutritional quality of processing tomatoes intended for whole-peel and diced products.
The cause of color disorders, such as yellow shoulder disorder (YSD),
involves an interaction between plant genotype and the environment.
Soil factors that correlate with the incidence of YSD are soil K, K:Mg
ratios, organic matter, and phosphorus. Fields with an organic matter
above 3.5% have a lower incidence of YSD. Progress in developing an
integrated crop management system that growers and processors can
use to profitably improve quality and nutritional value while reducing
color disorders of tomato has been made. Decision tools for managing
color disorders have been developed. Varieties of tomato differ in their
susceptibility to color disorders; thus, variety use may offer growers
a strategy to manage fields with low potassium, phosphorus, or low
organic matter. Soil K application through drip irrigation was effective
when applied at full bloom when the plants were most actively growing.
Trials conducted in Indiana and Ohio during the 2003 and 2004 growing
seasons demonstrated that weekly K application as a batch injection or
solid application improved fruit color and reduced internal whitening.
The effect of K addition is toward improved hue and L (lower values),
but that trend is not always statistically significant and variety-specific
responses are observed. Environmental factors for this response are
explored. Managing this complex color disorder will entail minimizing
risk of incidence, rather than preventative or curative applications.
(217) An Evaluation of Sulfur Status and the Effects of S
on Uptake, Distribution, and Yield of Processing Carrots
(Daucus carota L.)
F. Christine Pettipas1, Rajasekaran R. Lada*1, Claude D. Caldwell1,
Steve Kyei-Boahen2
1
Nova Scotia Agricultural College, Plant and Animal Sciences, Cox Institute, Truro, Nova
Scotia, Canada; 2Mississippi State University, Delta Research and Extension Center
(218) Optimum Soil K Application and Sufficient Leaf K
concentration for Fresh Market Tomatoes Grown on a
Midwest Fine Textured Soil
Henry G. Taber*
Iowa State University, Horticulture, Ames, IA, 50011
Tomato transplants were set mid-May 1998, 1999, and 2001, with
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(219) Nitrogen Relationships to Yield and Quality of
Carrots Grown on Mineral and Organic Soil in Ontario
Sean Westerveld1, Alan McKeown*2, Mary Ruth McDonald1
1
University of Guelph, Plant Agriculture, Guelph, Ontario, Canada; 2University of Guelph,
Plant Agriculture, Simcoe, Ontario, Canada
In previous work with carrots (Daucus carota L.), little effect of
nitrogen could be found on yield, but low nitrogen increased foliar disease. To determine if residual soil nitrate supplies sufficient
nitrogen for carrots, plots were located on the same site for 3 years.
Two sites were selected, one sand (pH 8.1, 2.6% OM), one organic (pH
6.0, 75% OM). Treatments consisted of 0%, 50%, 100%, 150%, and
200% of recommended levels (kg·ha-1) for organic (60) and mineral
soils (110), plots were spilt in half with one fertilized every year, one
in 2002 and were arranged in a split plot design with four replications.
Foliar and soil samples were taken for nitrate analysis plus levels of
Alternaria dauci and Cercospora carotae foliar blight were recorded
each year. Applied nitrogen had no effect on yield on muck soils.
Over 3 years on mineral soils, total yield ranged from 36 to 48 t·ha-1
with no applied N. On mineral soils, yield was maximized at (kg·ha1
) 110, over 165, and 55-165 in 2002, 2003, and 2004, respectively.
Stands on mineral soils were reduced at or above recommended rates
in 2004. It is possible that carrots obtained considerable nitrogen
perhaps deep in the soil profile. As in previous studies, applied nitrogen reduced foliar blights. Thus, nitrogen application is required for
pest management purposes even if there is almost sufficient residual
nitrogen for yield.
(220) Determination of Water and Nitrogen
Requirements of Cabbage using Fertigation
POSTERS–THURSDAY
A reduction in the atmospheric deposition of sulfur (S) and S-containing fertilizers has greatly reduced S inputs to the soil in recent years.
At the same time, S removal from the soil has increased as a result
of increased crop production and higher yields. Sulfur deficiency has
been found to reduce yields in several crops. A study was conducted
to gain an understanding of the S status of Nova Scotia soils that
support carrot production, as well as to examine the effects of rate
of S application, method of S application, and type of S fertilizer on
carrot uptake, distribution, yield, and recovery. Initial S concentrations in carrot-producing fields ranged from 52–440 kg·ha-1 of S. In
general, King’s County soils were lower in S than Colchester County
soils. In the S trial, banding and broadcasting S on the side of carrot
rows improved yield, and recovery compared to placing the S in the
seed row. Banding S also significantly increased undersize carrots,
leaf fresh weight, leaf dry weight, and root fresh weight. Rate of S
application did not affect yield, recovery, or growth of carrots. At
this time, S supplies from the atmosphere and soil are sufficient to
meet the demands of carrots produced for processing in Nova Scotia.
Growers do not need to apply S as fertilizer at this time to improve
carrot yields. Monitoring of the S status of soils should be periodically conducted to assess S concentration as SO2 emissions and crop
production continue to change.
black plastic mulch and a single line source drip irrigation system. The
soil type was a well-drained, central Iowa loam (prairie developed on
glacial till) with 2.4% organic matter, 13.1 CEC, and a pH of 6.8. The
soil test level of 89 kg·ha-1 of K was considered low for field corn and
would require 121 kg·ha-1 of K for optimum yield. The experimental
design was a factorial, split-plot, randomized complete block with
four replications. The whole unit was K rates (0 to 372 kg·ha-1 of K as
KCl). The subunit was cultivar, either ‘Mtn. Spring’ (a determinate)
or ‘Jet Star’ (an indeterminate). Fruit harvest began the first week of
August and continued weekly for 5 to 8 weeks. As expected, ‘Jet Star’
produced from 12% to 35% more total fruit than ‘Mtn. Spring’. The K
response was best described by a quadratic function. Total maximum
yield occurred from 325 to 372 kg·ha-1 of K, depending on the production year. Cullage was high, mostly as a result of ripening disorders,
and ‘Jet Star’ consistently produced more culls than ‘Mtn. Spring’,
10% to 11%. Increasing soil K rate did not reduce the percentage of
culls. For 2001, increasing K rate to 300 kg·ha-1 of K enhanced ‘Mtn.
Spring’ marketable fruit size 18%, from 258 g to 305 g each, but not
‘Jet Star’, which remained at 258 g. There was a difference (P < 0.01)
between the varieties for leaf K; ‘Mtn. Spring’ consistently had higher
K concentrations, from 0.2% to 0.4%. The leaf K sufficiency range
at the rapid flowering and vegetative growth stage was determined to
be 3.10% to 3.25% with the corresponding petiole leaf sap K (using a
dilution of 1 sap : 1 water) of 5000 mg·kg-1, for the same time period.
The correlation between the Cardy meter petiole sap K values and
whole leaf K was r = 0.83.
Alan McKeown*, Cathy Bakker
University of Guelph, Plant Agriculture, Simcoe, Ontario, Canada
Fertigation is a promising strategy to improve nitrogen use efficiency,
yield, and quality of cabbage (Brassica oleracea var. capitata),
but there is a lack of data relevant to growers in Ontario. Field trials
were conducted in 2003 and 2004 to determine the optimum rate
of water and nitrogen application in terms of yield and quality of
‘Huron’ cabbage. Treatments consisted of combinations of target soil
moisture levels (25% to 100% field capacity) and nitrogen fertilizer
(0–400 kg·ha-1 N) as dictated by a central rotatable composite design.
Nitrogen applications were split with 50% broadcast and incorporated
before planting and the remaining split into weekly applications via
a trickle irrigation system. Water was applied two to three times per
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week to bring soil moisture up to the target levels. Maximum marketable yield was reached at a combination of 400 kg·ha-1 N and a soil
moisture target of 100% field capacity. Many heads were undersized
or undeveloped at low rates of nitrogen. Applications of nitrogen required for high yield and quality can pose a risk of leaching; however,
use of fertigation minimizes potential in-season leaching. Estimated
total residual nitrogen at harvest ranged from 83–211 kg·ha-1 N,
which could have a negative impact on the environment. Thus, there
is a considerable challenge to reduce environmental impact without
economic losses. Improved knowledge of in-season nitrogen requirements might further reduce the levels of nitrogen applied without
reducing yield and quality.
(221) Controlled-release Nitrogen Fertilizer Release
under Field Temperature and Precipitation Conditions
for Potato Production in Northeast Florida
Jeffery Pack*, Chad Hutchinson
University of Florida, Horticultural Sciences, Gainesville, FL, 32608
Potato production in the Tri-County Agricultural Area of northeast
Florida accounts for nearly half of the state’s $120 M, 18-K hectare
annual crop. Concern over nitrate movement into watersheds from
potato production have stimulated research into alternative fertilizer
sources and practices. This study evaluated the potential of several
controlled-release fertilizer (CRF) products to release nutrients over
a 100-day growing season under field temperature and precipitation
conditions. In 2003 and 2004, 6 and 3 CRF products were evaluated,
respectively. Meshbags containing 3 g of product mixed with 200 g
of soil were buried 15 cm below the top of the potato row. Meshbags
were removed at 2-week intervals. Samples were dried and sieved to
remove soil. Fertilizer prills were ground and mixed with DI water to
dissolve residual fertilizer. Samples were analyzed for total N by the
Dumas (combustion) method (2003) or for TKN (2004). In 2003, initial
release (after 20 days) ranged from 23% to 85% for the six products.
In 2004, initial release (after 9 days) ranged from 34% to 65% for
the three products. In 2003, total N release from CRF prills after 104
days ranged from 72% to 99%. In 2004, total N release from samples
ranged from 79% to 92% release after 91 days. The shape of the release
curve described some release patterns comparable to water-soluble
fertilizers while others exhibited sustained-release properties. If release
characteristics are designed to match potato plant uptake requirements
in time and quantity, CRF products may be used to reduce off-site N
movement while maintaining potato production.
(222) The Residual Effect of Organic Amendment
Applications on the Yield of Sweet Corn, Zucchini, and
Mustard Cabbage
Hector Valenzuela*, Roger Corrales, Ted Goo
University of Hawaii at Manoa, CTAHR, Honolulu, HI, 968222
A major issue in the preparation of nutrient budgets for organic farmers
is the residual nutrient effect from organic amendments available for
follow-up crops in year-round rotation systems. A series of separate
experiments were conducted to evaluate: 1) the residual nutrient effects on double-cropped sweet corn from initial applications of several
organic amendments locally available in Oahu, Hawaii; 2) the residual
effect of double cropped zucchini; and 3) mustard cabbage from the
application of similar organic amendments. The sweet corn experiment
consisted of six treatments, with organic amendments applied only
prior to the first planting. The second follow-up sweet corn planting
was grown without additional amendment applications. Treatments
included: 1) a fruit fly based compost; 2) aged chicken manure; 3) bone
meal; 4) synthetic fertilizer (farmer’s practice); 5) a combination of
compost and fertilizer; and 6) a combination of compost and chicken
manure. The experiment was arranged with a randomized completeblock design. Each treatment plot consisted of two 20-m long rows of
corn with five replications per plot for a total of 30 treatment plots. On
a separate location similar trials were conducted on long-term organic
farming plots, with double cropped zucchini and with double cropped
mustard cabbage. The results from this research shows that crop yields
were similar or greater under the organic amendment plots compared
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final6_20July HS.indb 1074
to the synthetic fertilizer plots. In crops with a high N uptake demand,
yields from the organic amendment plots declined by about 10% in
follow-up plantings. This data will allow organic farmers to prepare
nutrient budgets to better match their organic fertilizer applications
with crop nutrient demands.
(223) The Effect of Commercial Home Garden Fertilizers
on the Growth and Yield of Two Chinese Cabbage
Varieties
Hector Valenzuela*, Ted Goo, Ray Uchida, Susan Migita
University of Hawaii at Manoa, CTAHR, Honolulu, HI, 96822
Home gardening is a popular year-round recreational activity in Hawaii
that helps to increase community food security in suburban and rural
communities where high levels of poverty and unemployment exist.
Updated fertilizer recommendations and accurate information about the
latest products allows home gardeners to improve crop growth, and to
minimize nutrient imbalances in the soil, pest problems, and environmental risks from nutrient runoff or leaching. Two field experiments
were conducted in Oahu, Hawaii, to evaluate several new products in
the market for the production of two home-garden Chinese cabbage
varieties. The treatments included Miracle Grow, a new Miracle Grow
Plus formulation, Plant Power 2003 nutrient solution, a Maui Liquid
Compost product, and a standard fertilizer control (150 kg·ha-1 N rate).
Each treatment consisted of a 6-m long row with 30-cm plant spacing
in the row. Each treatment was replicated four times in a completely
randomized block design, for a total of 40 plots (two varieties × five
treatments × four replications). Data collected included soil fertility
before initiation and after experiment completion, tissue nutrient
analysis, plant height collected twice during the growing cycle, and
head weight and length measured at harvest time. The variety Pagoda
was more responsive to fertilizer applications, showing an average of
30% yield increases between the best and poorest treatment, compared
to 20% for ‘China Express’. Overall, the Miracle Grow formulations
outperformed the other products. The tissue nutrient data showed tissue
nutrient levels above those recommended by the Extension Service. The
treatments with highest yield response also showed greater symptoms
of “black heart” from possible boron deficiency.
(224) In Situ N Monitoring for Safe Leafy Vegetables
using Quick and Advanced Tools
Chin H. Ma, Manuel C. Palada*
AVRDC–The World Vegetable Center, Crop & Ecosystem Management, Shanhua, Tainan,
74151, Taiwan
High levels of N fertilizers are generally applied in intensive leafy
vegetable production in the peri-urban agriculture of Southeast Asia.
This study was conducted to develop a simple and rapid method of
determining nitrate-N accumulation in selected leafy vegetables.
Five leafy vegetables, including amaranth (Amaranthus tricolor),
kangkong (Ipomoea aquatica), Ethiopian kale (Brassica carinata),
choysum (Brassica campestris sp. parachinensis), and leafy lettuce
(Lactuca sativa) were grown on raised beds in 32-mesh nethouse in
randomized complete-block design with four replications. The crops
were fertilized with eight N levels: 0, 50, 100, 150, 200, 250, 300,
and 350 kg·ha-1 in three splits. At harvest, nitrate contents were determined in tissue sap of fully expanded leaf blades, petioles and whole
plant using a Cardy nitrate meter. Chlorophyll content readings were
also measured on the same leaf using a chlorophyll meter. Nitrate
accumulations varied with vegetable species. Significant correlations
(P < 0.001) existed between N fertilizer rate and nitrate content as
well as leaf chlorophyll and yield. Using N application rate of 200
kg·ha-1, nitrate accumulation in Ethiopian kale was highest (7000
ppm), followed by kangkong (4000 ppm), amaranth (3500 ppm), and
leafy lettuce (1200 ppm). The correlation between leaf chlorophyll
meter reading (LCMR) and nitrate content was also significant (P <
0.001), suggesting the feasibility of using Cardy nitrate meter test and
LCMR for monitoring production of low-nitrate and safe vegetables.
The Cardy meter was also sensitive in detecting soil nitrate-N below
20 ppm and is a rapid and reliable alternative to conventional distillation method.
HORTSCIENCE, VOL. 40(4), JULY 2005
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(225) Challenges and Opportunities with Vegetable BMPs
in Southwest Florida
(227) Does Salinity Reduce Boron’s Toxic Effect in
Broccoli?
Monica Ozores-Hampton*1, Eric Simonne2, Eugene McAvoy3,
Phil Stansly4, Sanjay Shukla5, Pam Roberts6, Fritz Roka7,
Tom Obreza8
Stephen R. Grattan*1, Catherine M. Grieve2, James A. Poss2,
Timothy E. Smith3, Donald L. Suarez2
1
2
University of Florida/SWFREC, Horticulture, Immokalee, FL, 34142; University of
Florida, Horticulture, Gainesville, FL, 32611; 3University of Florida/IFAS, Hendry Co.
Coop. Ext. Office, Labelle, FL, 33975; 4University of Florida/SWFREC, Entomology,
Immokalee; 5University of Florida/SWFREC, Agricultural and Biological Engineering,
Immokalee; 6University of Florida/SWFREC, Plant Pathology, Immokalee; 7University
of Florida/SWFREC, Food and Resource Economics, Immokalee; 8University of Florida/
IFAS, Soil and Water Sciences, Gainesville
About 10,000 ha of staked tomato are grown each year in the winter–spring season in southwest Florida. Tomatoes are produced with
transplants, raised beds, polyethylene mulch, drip or seepage irrigation, and intensive fertilization. With the development of nutrient
best management practices (BMPs) for vegetable crops and increased
competition among water users, N recommendations must ensure economical yields, but still minimize the environmental impact of tomato
production. The current University of Florida–IFAS (UF–IFAS) N
fertilization rate of 224 kg·ha-1 (with supplemental fertilizer applications under specified conditions) may require adjustment based on soil
type and irrigation system. Because growers should be involved in the
development and implementation of BMPs, this project established
partnerships with southwest Florida tomato growers. Studies evaluated the effects of N application rates on yield, plant growth, petiole
N sap, pests, and diseases. Nine on-farm trials were conducted during
the dry winter 2004–05 season. Treatments consisted of N fertilizer
rates ranging from 224 to 448 kg·ha-1, with each trial including at least
the UF–IFAS rate and the traditional rate. Although total yields were
comparable among N rates, there were differences in size category.
Nitrogen rates had little effect on tomato biomass 30 and 60 days
after transplanting. Changes in petiole sap NO3-N and K concentrations were different between seepage and drip irrigation, but usually
above the sufficiency threshold. It is important to consider the type
of irrigation when managing tomato and determining optimum N
fertilizer rates.
(226) Tomato Cultivar Differences in Ion Uptake and
Growth in Closed Hydroponic Culture
Hyung Jun Kim1, Chris Harlow2, Mary Peet*2
1
National Horticultural Research Institute, Div. Protected Cultivation, Imok-Dong 475,
Gangan-Gu, Suwon, 440-706, Korea; 2North Carolina State University, Horticultural
Science, Raleigh, NC, 27695-7609
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final6_20July HS.indb 1075
High salinity and boron often occur together in irrigation water in
arid climates, but very little research has been done to study the
interaction of the two. A greenhouse experiment was conducted at
the US Salinity Laboratory in sand tanks to evaluate the interactions
between B and saline drainage water on the performance of broccoli.
Particular interest in this study was directed towards the composition
of the salinizing solution to determine what role various salts have
on the salinity-boron interaction. Results from this study indicate
that both Cl-based salts and those characteristic of saline drainage
water (i.e., a mixture of salts dominated by sodium sulfate) showed
a significant salinity–boron interaction. At high salinity, increased B
concentration was less detrimental, both visually and quantitatively
(i.e., biomass), than it was at low salinity. That is, plants could tolerate
a higher solution B-concentration at higher salinity. However, there
was no significant difference between salt types. The effects on head
weights were more exaggerated than those on shoot biomass. Shoot B
concentration was influenced by salinity, but interestingly the direction
of influence was dependent upon the B concentration in the solution.
Regardless of the composition of the salinizing solution, increased
salinity increased shoot B concentration when B concentrations in
the solution were relatively low (i.e., 0.5 mg·L-1). At the highest solution B concentration (28 mg·L-1), increased salinity reduced shoot B
concentration. Solution B in itself had very little influence on shoot
ion accumulation, but both salinity (i.e., EC) and salinity composition
had very strong influences on shoot tissue ion composition. Therefore,
these data indicate that salinity and B are antagonistic.
Poster Session 46—Temperature Stress Physiology
21 July 2005, 12:00–12:45 p.m. Poster Hall–Ballroom E/F
(430) Leaf Gas Exchange of Carrots in Response to
Increasing Leaf Temperatures
F. Christine Pettipas1, Rajasekaran R. Lada*1, Robert Gordon2,
Tess Astatkie2
1
2
Nova Scotia Agricultural College, Plant and Animal Sciences, Truro, Nova Scotia, Canada;
Nova Scotia Agricultural College, Engineering, Truro, Nova Scotia, Canada
Increasing temperature as a result of global climate change is expected
to exert a great influence on agricultural crops, possibly through effects on photosynthesis. Response to temperature of leaf gas exchange
parameters of carrot (Daucus carota L. var. sativus) cultivars Cascade,
Carson, Oranza, and Red Core Chantenay (RCC) were examined in a
controlled growth room experiment. Leaf net photosynthetic rate (PN),
stomatal conductance (gs), and transpiration rate (E) were measured
at temperatures ranging from 15 to 35 °C at 370 μmol·mol-1 (CO2)
and 450±20 μmol·m-2·s-1 PAR. The cultivars responded similarly to
increasing temperature and did not differ in most photosynthetic parameters except gs. The PN increased between 20 and 30 °C, thereafter
increasing only slightly to 35 °C. On average, increasing temperature
from 20 to 30 °C increased PN by 69%. Carboxylation efficiencies
(Ca/Ci ratio) ranged from 1.12–2.33 mmol·mol-1 while maximum PN
were 3.25, 3.90, 5.49, 4.19 μmol·m-2·s-1 for Carson, RCC, Cascade, and
Oranza, respectively. The E did not reach maximum at 35 °C while gs
peaked at 30 °C and then decreased by 93% at 35 °C. The water use
efficiency (WUE) decreased with an increase in temperature due to
increases in both PN and E. The results indicate that increasing temperatures above the seasonal average (<20 °C) increases both PN and
E up to 30–35 °C. An increase in photosynthesis due to an increase
in temperature is expected to hasten growth. Carrots may be able to
withstand a moderate increase in temperature.
POSTERS–THURSDAY
The objective of this study was to compare nutrient ion uptake and
growth of Lycopersicum esculentum Mill. cvs. Trust, widely grown
in North America, and Momotaro, widely grown in Korea and
Japan. Tomatoes were planted July 2004, two per pot, in 36 perlite-filled pots fertigated with modified Steiner solution in a closed
system. Inorganic ions (K, NO3-N, Mg, P, S) in the nutrient solution
were measured weekly. Weekly solution uptake rate for both cultivars
increased from 70 mg·MJ-1 irradiance at 36 days to 200 mg·MJ-1 at
133 days (end of experiment). The uptake rate of ‘Trust’ was lower
than ‘Momotaro’ until 92 days after planting, then higher for the
remainder of the experiment. This corresponded to lower leaf area
in ‘Trust’ prior to 92 days, then greater leaf area than ‘Momotaro’.
Similarly, the nutrient uptake rate (ppm) of K, Ca, Mg, and S ions in
‘Trust’ were lower than ‘Momotaro’ until 92 days and higher after
92 days. The P uptake showed the opposite pattern with a higher uptake rate in ‘Trust’ than ‘Momotaro’ until 92 days and lower uptake
thereafter. The N uptake rate did not differ between the cultivars.
Thus, except for P and N, uptake of individual ions was proportional
to total nutrient solution uptake. Plant height, number of clusters and
total leaf area at 133 days was higher in ‘Momotaro’ but fruit number
and total aboveground dry weight (leaf, stem, and fruit) was higher in
‘Trust’. Percentage of total dry weight, represented by leaf and fruit
in ‘Momotaro’, were 40% and 41%, respectively, and 30% and 57%,
respectively in ‘Trust’.
1
University of California, Land, Air and Water Resources, Dept of LAWR, Davis, CA,
95616; 2USDA-ARS Salinity Laboratory, Plant Science, Riverside, CA, 92507; 3Reedley
College, Plant Science, Fresno, CA, 93704;
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6/20/05 5:02:33 PM
(431) Evaluation of Anti-transpiration Organic Materials
on Strawberry Performance
Sorkel Kadir*1, Said Ennahli2, Ben Glass3
1
Kansas State University, Horticulture, Forestry, & Recreation Resources, Manhattan, KS,
66506; 2Kansas State University, Horticulture; 3Kansas State University, Agronomy
Interactive effects of different temperature regimes and anti-transpiration organic materials, Surround WP (kaolinite clay) and Raynox
(sun-protectant), on two strawberry (Fragaria ×ananassa) cvs.
Chandler and Sweet Charlie were investigated under controlled
environmental conditions. Newly planted strawberries treated with
Surround and Raynox were subjected to 20/15, 30/25, and 40/35 °C
(day/night) temperature regimes and 16 day/8 night photoperiod in
growth chambers for 42 d. Photosynthesis (A) and photochemical
efficiency (Fv/Fm) were measured at 7-d intervals during the experiment. Plants treated with Raynox displayed greater resistance to high
temperature (40/35 °C) compared to those treated with Surround. Net
photosynthesis of both cultivars decreased significantly with time at
40/35 °C. There was no significant difference in photosynthetic rate
between the two cultivars. Nevertheless, there was difference in plant
biomass between the cultivars. Raynox provided more protection
against high temperature, specifically in reducing stomatal conductance
and limiting transpiration, than Surround.
(432) Heat-tolerant Traits of Salvia (Salvia splendens)
Seenivasan Natarajan*, Jeff Kuehny
Louisiana State University, Horticulture, Baton Rouge, LA, 70808
One of the greatest impediments to the production of marketable ornamental herbaceous plants in the southern U.S. is high temperature stress.
Exposure of plants to sublethal temperature (heat preconditioning)
prior to sustained heat stress helps some plants to tolerate subsequent
heat stress, a phenomenon often referred as acquired thermotolerance.
The objective of this experiment was to examine various morphological, physiological, and anatomical responses of two red varieties of
each of the ‘Vista’ (heat tolerant) and ‘Sizzler’ (heat sensitive) series
of Salvia splendens to heat preconditioning (HC) and subsequent
heat stress treatments [challenging temperatures (CT)]. Cultivars of
salvia were subjected to short duration (3 hours) HC of 35 °C every
third day until 5 weeks after germination and subsequent exposure
to two CT treatments: 30/23 °C and 35/28 °C (day/night) cycles in
growth chambers until flowering. Plant growth, marketable quality,
stomatal conductance and net photosynthesis declined for ‘Sizzler’
without HC treatment. Compared with nonpreconditioned plants,
heat-preconditioned ‘Sizzler’ had 38.28% higher root dry weight, 95%
greater leaf thickness, and 50% higher marketable quality at 35/28
°C heat stress condition. Heat preconditioning helped both ‘Vista’
and ‘Sizzler’ to survive in both the heat stress treatments. ‘Vista’ had
greater heat-tolerant traits than ‘Sizzler’; these traits were enhanced
with heat preconditioning treatment. The results demonstrated that heat
preconditioning enhanced heat tolerance in varieties of salvia, which
could be related to heat-tolerant traits, such as dense plant growth with
shorter internodes, thicker stems, greater stomatal conductance, and
extensive root growth that compensated for the transpiration water
loss and cooling effect.
(433) Gas Exchange and Chlorophyll Fluorescence
Responses of Closely Related Pepper Genotypes to High
Temperature Stress
John Jifon*, Kevin Crosby, Daniel Leskovar
Texas A&M University, Horticulture,Weslaco, TX, 78596
High temperature stress is a major limitation to commercial production
of habanero pepper (Capsicum chinense Jacq.) in tropical and subtropical regions. The ability to sustain physiological activity under stress is
an important trait for newer varieties. We evaluated leaf thermotolerance
[based on the cell membrane stability (CMS) test] of three habanero
pepper varieties to: 1) determine genetic variability in CMS among
the genotypes studied; and 2) to assess correlations between CMS,
photosynthesis and chlorophyll fluorescence [(CF), an indicator of
membrane-dependent photosystem II quantum efficiency, ΦPSII]. The
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final6_20July HS.indb 1076
genotypes evaluated were TAM Mild Habanero (TMH, a recently developed mild habanero pepper) and its closely related parents (Yucatan
and PI 543184). Net CO2 assimilation rate (An) of intact leaves was
measured in the field and leaf samples collected and exposed to heat
stress (55 °C for 20 min) in temperature-controlled water baths under
dim light conditions. The CF was assessed before and after the heat
treatment. The CMS was highest in PI 543184, lowest in TMH and
intermediate in Yucatan. All genotypes maintained high An rates in the
field (25 ± 6 μmol·m-2·s-1); however, correlations between An and CMS
were weak. The Φ values were similar among the genotypes (~0.8)
under nonstress conditions, but differed significantly following stress
exposure. PI 543184 had the highest post-stress ΦPSII values (0.506
± 0.023), followed by Yucatan (0.442 ± 0.023) and TMH (0.190 ±
0.025). Observed differences in CMS and ΦPSII indicate plasticity in
the response to heat stress among these genotypes.
(434) Changes in Gene Expression Are Regulated by
Temperature Stress in Pachysandra terminalis
Suping Zhou*, Roger Sauve, Tingting Chen, Sara Bhatti,
Debrah Long
Tennessee State University, Institute of Agricultural and Environmental Research Nashville, TN, 37209
Identification of low temperature–regulated gene expression in Pachysandra terminalis: Pachysandra terminalis is a cold-hardy, evergreen
plant species. In order to identify molecular mechanism of cold tolerance of this plant species, seedlings with four fully expanded leaves
were subjected to 4, 0, and –1 °C low temperature treatments. Low
temperature–induced genes were identified from treated plants using
cDNA differential display. The cDNA fragments were cloned onto
PCR-trap vectors. Low temperature regulation of these genes was
confirmed by reverse-northern blot. Sequence analysis has identified
that these genes can be classified into three groups, stress-related,
photosystem-related. Most of the genes cannot find matching sequences in the database. To further study the regulation of these genes
by temperature fluctuation, the plants were treated at 4, 0, and 40 °C.
Northern blot analysis showed that several clones showed increased
expression after cold and heat shock. Previous cold treatment at 4
°C can negate the effect of heat shock on expression of these genes.
Complete sequence of these genes is cloned from the cDNA library
and their temporal regulation by environmental stresses is analyzed
using real-time PCR.
(435) Physiological Study of Deacclimation and
Reacclimation in Deciduous Azalea (Rhododendron
subgenus Pentanthera) Species
Scott Kalberer1, Norma Leyva-Estrada2, Stephen Krebs3,
Rajeev Arora*1
1
Iowa State University, Horticulture, Horticulture Hall, Ames, IA, 50011; 2Iowa State
University, Dept. of Statistics, Ames, IA; 3Holden Arboretum, Horticulture Sciences,
Kirtland, OH, 44077
Winter survival of temperate-zone woody perennials requires them
to resist loss of frost hardiness (deacclimation) during winter and
early spring thaws. However, little is known about deacclimation
response in woody landscape plants. Moreover, what impact, if any,
the degree of deacclimation has on reacclimation capacity has not been
systematically studied. We used nine genotypes of deciduous azaleas
(Rhododendron subgenus Pentanthera) to investigate effects of deacclimating conditions on bud cold hardiness and reacclimation ability.
Dormant floral buds, with 3–5 cm stem attached, were collected in
late December from field-grown plants, and placed in constant warm
[22 °C 15 °C (D/N)] and humid conditions for increasing durations
(0-day to 14-day) to stimulate deacclimation. Bud cold hardiness
(LT50) was determined (using logistic regressions) by evaluating immature flower survival at subfreezing treatment temperatures. Results
indicated that azalea genotypes from colder provenances showed
greater initial frost hardiness. Typically northern genotypes had slow
to intermediate deacclimation rates, while rates of southern genotypes
were intermediate to rapid. High initial frost hardiness was frequently
associated with slow deacclimation. Buds retained the capacity to
HORTSCIENCE, VOL. 40(4), JULY 2005
6/20/05 5:02:35 PM
reacclimate upon cold exposure [2 °C/–2 °C; (12 h/12 h)] even after
8 days of deacclimation. Distinct differences were observed between
the two latitudinal ecotypes of R. viscosum with respect to their initial
bud hardiness, deacclimation rates, and reacclimation capacities. We
suggest that the three attributes, i.e., high initial hardiness, slow deacclimation, and high reacclimation capacity, together may be important
for winter-survival of azalea buds.
(436) Comparative Cold Hardiness and Freezing
Behavior of Leaves, Buds, and Flowers in Selected
Woody Plants in Northern Latitudes
A.M. Shirazi*, M.V. Thierry
The Morton Arboretum, Urban Horticulture Lab., Lisle, IL, 60532
It is not well known how cold-hardy new buds and emerging leaves
or flowers are during spring. Extreme temperature fluctuations that
sometimes bring early frost in spring (April–May) are very common
in northern latitudes and cause severe damage to emerging leaves and
flowers. Even though most woody plants can tolerate frost in spring,
others show early tissue damage and can fully recover. There are some
trees, e.g., Japanese maples (Acer palmatum) that when leaves are
damaged due to spring frost, the results include severe dieback and
eventual death. We tested new flowers and leaves of four crabapples:
Malus ×micromalus, M. sargentii, ‘Mary Potter’, and M. hupehensis,
after budbreak for 3 years using electrical conductivity (EC) and
differential thermal analysis (DTA) in spring: May 1997, Apr. 1998,
and Apr. 2000, at The Morton Arboretum. Both flowers and leaves
can tolerate from –6 to –12 °C and we observed higher ion leakage in
leaves than flowers. The high temperature exotherm (HTE) of flowers
were –8 to –10 °C in April. In a companion study, testing other species
that had premature budbreak due to “near lethal” (sublethal) freezing
stress in Jan. 2001, the following HTE were observed: Cornelian cherry
(Cornus mas) flower (about –7.5 °C), Spindle trees leaves (about –6
°C), Judd’s viburnum (Viburnum ×juddii) (about –8 °C), Brevipetala
witch-hazel (Hamamelis mollis ‘Brevipetala’) flower (about –5 °C),
redbud (Cercis candensis) flower (about –9 °C), flowering quince
(Chaenomeles ×superba) flower (–8 °C). Multiple LTE at –13, –18,
–22, and –27 °C were observed for Judd’s viburnum. This information
could be useful for selection and breeding of woody plants.
(437) Application of Differential Thermal Analysis to
Study Freezing Behavior and Supercooling in Plants
A.M. Shirazi*, M.V. Thierry
The Morton Arboretum, Urban Horticulture Research Lab., Lisle, IL, 60532
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A.M. Shirazi*, G.H. Ware
The Morton Arboretum, Urban Horticulture Research Lab., Lisle, IL, 60532
The genus Ulmus contains numerous stress-tolerant species, especially
those from areas of China with climates similar to various regions of
the United States. Lace-bark elm, Ulmus parvifolia, the true Chinese
elm, has an extensive temperature distribution range in China and offers great promise as a street tree. The high resistance of this elm to
Dutch elm disease and other elm problems makes it an excellent tree
for urban landscapes. Two new U. parvifolia cultivars, Athena® and
Allee®, are not cold hardy for northern climates and there is a need for
new cold hardy lace-bark elms. Screening thousands of seedlings for
cold hardiness, upright form, beautiful bark characteristics, and larger
leaves will bring the most desirable U. parvifolia cultivars into the
green industry. We determined that seed dormancy and the percentage
of seed germination of four selected lacebark elms after 2 and 4 weeks
were >30% and >50%, respectively. There were significant differences
in stem cold hardiness among new lace-bark elms from China (about
–32 to –40 °C). Laboratory determination of cold hardiness can provide
great advantages over years of field testing. Response to the outdoor
temperature in December, January, and February on a seed cold hardiness freezing test showed significant reduction in seed germination,
especially at –30 °C. Freezing test of seeds to –40 °C, resulted in LT50
of –3 to –5 °C in December, so, it is less likely that these U. parvifoilia
will become invasive in northern latitudes. Invasiveness of these U.
parvifolia for higher zones, e.g., 6–8 could be greater and selection
of these elms is suitable for zones 5 and lower. Planting these elms
in zones 4, 3, and 2 will give us useful information regarding their
winter performance.
(439) Influences of Low Temperature and Xylem Bubble
Treatments on Deformed Leaves in ‘Hayward’ Kiwi Trees
Wol-Soo Kim*, Xiu-Yu Wu, Soon-Ju Chung
Chonnam National University, Department of Horticulture, 300 Yongbong-dong, Gwangju,
500-757, Korea
During the early spring, embolism symptoms may be observed on
the leaves of kiwi trees after a severe, cold winter. The morphological
character of embolism in young leaves in early spring is typically parachute shaped, at the basal part of kiwi shoots. Deformed leaves were
observed at the beginning stage of development. To test the factors,
we used water stress, low temperature, and xylem bubble treatments
on kiwi vines during the winter season. Low temperature treatments
on trees were carried out in a –15 °C chamber for 0, 12, 24, and 48
hours. For the xylem bubble treatment, the trees were injected with
3.5 MPa compressed air at –15 °C for 24 hours. For water stress treatments, the trees were not irrigated until dry soil conditions reached
as little as 50% soil moisture. Treated kiwi trees planted in plastic
pots (20 cm × 25 cm) were moved into the growth chamber at 25 °C
with 12 hours of light, and the rate of deformed leaf symptoms was
observed. In all treatments, deformed leaves were observed and bud
burst rates were lower than for the control. Therefore, we confirmed
that the main factors for deformed leaves were low temperature, xylem
bubbles, and water stress.
(440) Flowering and Fruiting in Olives in the Absence of
Chilling Temperatures
POSTERS–THURSDAY
Survival of temperate plants is often dependent upon their resistance or
ability to tolerate low temperatures. Differential thermal analysis (DTA)
has been employed to explore the freezing characteristics of plants
and other organisms. However, there appears to be a need for further
studies to better understand the physiology of freezing and its significance as related to supercooling. Methods employing thermocouples,
differential wiring, and digital data acquisition boards allow detection
of very small exothermic responses (about 0.025 °C). This study reports
on techniques and apparatus for using DTA as well as results obtained
on various plant tissues. When Fagus grandifolia (American beech)
was compared to Fagus sylvatica (European beech ), it exhibited both
a lower high temperature (HT) and low temperature (LT) exotherm
that correlated with lower stem tissue water content during September
to May. The DTA on Acer pseudosieboldianum (Korean maple) from
a higher elevation showed lower LT exotherm in stem tissues when
compared to lower elevation samples. Incubation of Cornus amomum,
Cornus obliqua, and Larix gmelinii var. olgensis stem tissue with d-H20
for 20 hours resulted in an induction of LT exotherm at a significantly
higher temperature than a normal LT exotherm. This phenomenon was
attributed to the bark tissue in Larix gmelinii var. olgensis. Sucrose
and glycerol exotherm profiles exhibited lower exotherm temperatures.
In a companion study, we used thermal analysis (non-differential) to
study supercooling in [Homadaula anisocentra (Mimosa webworm)]
and a single exotherm event was detected. New technology provides
a great deal of flexibility in the method of evaluation of exothermic
responses in plants and other organisms.
(438) Searching for Cold Hardy Lace-bark Elm (Ulmus
parvifolia Jacq.) for Northern Latitudes
Nasir Malik*, Joe M. Bradford, Jim E. Brockington
USDA-ARS, IFNRRU, Weslaco, TX, 78596
Cultivation of olives was not developed in southern and coastal Texas
because it was assumed that the winters in this area do not provide
enough chilling for flowering. Our initial experiments have demonstrated
that olive trees of ‘Arbequina’ could flower and fruit under mild winter
conditions; i.e., without the typical chilling conditions (below 7.2 °C
are chilling temperatures, but 2–4 °C during the night was considered
optimal chilling) that have previously been considered necessary for
flowering and fruiting in olives. We propose that lack of flowering in
southern Texas is due more to high temperatures during the day (many
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days reaching 26 °C) than lack of chilling temperatures in the night.
Thus, ‘Arbequina’, and perhaps other cultivars of olives, should be
able to grow and flower and fruit normally in coastal Texas, where
daytime temperature do not rise as high as in southern Texas. A survey
of coastal Texas revealed that this is indeed a possibility, because a few
trees planted in areas of coastal Texas do flower and fruit. Experiments
have now been started at different sites to evaluate the performance of
olives in coastal Texas.
Poster Session 47—Ornamental/Landscape and Turf 2
21 July 2005, 12:00–12:45 p.m. Poster Hall–Ballroom E/F
accurate irrigation schedules consistently for every landscape setting
when compared to research-based reference comparison treatments.
Greater complexity and technicality of required setup information did not
always result in more accurate, water-conserving irrigation schedules.
Use of a weather-sensing controller does not assure landscape water
conservation or acceptable landscape plant performance, and it does
not eliminate human interaction in landscape irrigation management.
(110) Composition and Place of Origin of Trees in
Residential Neighborhoods and Embedded Parks in
Phoenix, Arizona
Chris A. Martin*
Arizona State University East, Department of Applied Biological Sciences, Mesa, AZ,
85212
(108) Assessing the Preparedness of College/Universitytrained Graduates Entering the Landscape Contracting
Industry
Kory Beidler*, Jeffery Iles
Iowa State University, Horticulture, Ames, IA, 50011
Using a mail questionnaire, we invited landscape contracting decision-makers to comment on the effectiveness of landscape contracting
programs at colleges and universities in preparing students for professional careers. After organizing the Associated Landscape Contractors
of America 2003 online member list (2049 companies) into four strata,
based on company size, we chose a stratified random sample of 400
companies for our study. Completed questionnaires were received
from 137 companies (35% response rate). A much larger percentage
of respondents were either satisfied or extremely satisfied (52%) with
college graduates recently hired than those who were dissatisfied or
extremely dissatisfied (8.1%). But, when asked to consider four knowledge categories, a majority (53%) said recent graduates are deficient in
business knowledge, whereas smaller percentages of respondents noted
deficiencies in construction (25.1%), horticulture (9.6%), and design
skills (5.1%). When asked to rate the importance of topics that could be
taught in undergraduate landscape contracting programs, respondents
identified business topics (personnel management, estimating and
bidding, and clientele management) as their top three choices. Respondents also named three business-related skills (client relationships,
time management, and managing employees) among the top five most
important skills for landscape contracting professionals. Despite the
stated importance of business training and business skills, more than
two-thirds (68.3%) of respondents said when hiring for an entry-level
landscape contracting position, they would prefer candidates with strong
horticulture skills over those with strong business skills.
(109) Evaluation of Weather-sensing Landscape Irrigation
Controllers
Dennis R. Pittenger*1, David A. Shaw2, William E. Richie1
1
University of California, Riverside, Cooperative Extension/Botany & Plant Sciences,
Riverside, CA, 92521; 2University of California, Cooperative Extension San Diego County,
San Diego, CA, 92123
We conducted an evaluation of three commercial weather-sensing irrigation controllers to determine the climatic data they use, how easy
they are to set up and operate, and how closely their irrigation regimes
match landscape irrigation needs established by previous field research.
The devices virtually controlled an existing reference irrigation system
and used its system performance data as required in their initial setup.
Reference standard treatments for cool-season turfgrass, trees/shrubs
and annual flowers were calculated using onsite, real-time reference
evapotranspiration (ETo) data and plant factors developed primarily from
previous research. The reference irrigation system applied the correct
amount of water to an actual tall fescue turfgrass planting whose water
needs served as the reference standard treatment comparison for the
cool-season turfgrass treatment. Virtual applied water was recorded for
other plant materials and it was compared to the corresponding calculated
reference standard amount. Results show each controller adjusted its
irrigation schedules through the year roughly in concert with weather
and ETo changes, but the magnitudes of adjustments were not consistently in proportion to changes in ETo. No product produced highly
1078
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This study evaluated the influence of social economic rank (SER) and
neighborhood and park age on the composition and place of origin of
trees in residential neighborhoods and embedded small urban parks in
Phoenix, Ariz. During 2000 and 2001, trees were surveyed within an
array of 16 residential neighborhoods and embedded small urban parks
that spanned a range of socioeconomic rank (SER) and age. Parks were
embedded within residential neighborhoods of similar density across
three SER classifications, high, moderate, or low. Neighborhoods
and parks ranged in age from about 1947 to 1997. Counts of all trees
in each park were made and neighborhood tree composition was approximated by tree counts along four transects, distributed away from
each park along streets in a northerly, easterly, southerly, or westerly
direction, respectively. Transect widths extended about the depth of
a front yard residence on both sides of the street. Park and surrounding neighborhood tree composition was calculated as total frequency
(abundance) and taxa frequency (diversity) per hectare of landscape
surface area. Tree abundance in parks was highest when surrounded by
neighborhoods of high SER. Neighborhoods of high SER had greater
tree diversity than neighborhoods of low SER. Distinct patterns of tree
origin, dictated by both classifications of SER and age, were found.
Overall, trees in residential neighborhoods and embedded parks tended
to be indigenous to arid regions of North America, South America,
Australia, south Asia, and China.
(111) Establishment of Root-bound Plumbago auriculata
Lam. in a Landscape
Sudeep Vyapari*1, Edmund L. Thralls2, Michele S. Scheiber2
1
University of Florida, Environmental Horticulture, UF/IFAS–Plant City Campus, Plant
City, FL, 33563; 2University of Florida, Environmental Horticulture, Mid-Florida Research
& Education Center, Apopka, FL, 32703
A study was conducted to evaluate establishment of root-bound vs.
nonroot-bound container-grown Plumbago auriculata Lam. in a
landscape. A total of 144 plants were transplanted from #1 containers
in a rain-out shelter at Mid-Florida Research and Education Center,
Apopka, Fla., in June 2004. The field soil type was amended with
composted yard waste. The three treatment types used for the study
were: 1) root-bound plants; 2) root-bound plants with a vertical slice
made through the root ball at a 90° angle; and 3) nonroot-bound plants.
To evaluate the effect of these three treatments during the course of
establishment period, harvesting was done once every 2 weeks. Data
on growth indices (height × width × width), shoot dry weight, root dry
weight, and length of the longest root were recorded. The experimental
design was a completely randomized design consisting of three treatments, 12 harvest dates (days after planting), and four replicates per
harvest date. Plants were maintained according to the best management
practices recommended by the UF/IFAS, and were irrigated once a day
using microirrigation. Experimental data were analyzed for significance
of correlation among variables using SAS version 9.1. Results of the
correlation and regression analysis indicated that the increase in the
shoot dry weights (g), root dry weights (g), growth indices (m3), and
root : shoot ratio had significant relationship with the harvest dates.
Correlation among harvest dates and shoot dry weight, root dry weight,
or growth indices was found to be positive. However, results of the
study indicated that as the number of days after planting increased, the
root to shoot ratio decreased.
HORTSCIENCE, VOL. 40(4), JULY 2005
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(112) Heat and Drought Affect Photosynthesis of Sugar
Maple (Acer saccharum) Ecotypes
Jason J. Griffin*
Kansas State University, Dept. of Horticulture, Forestry and Recreation Resources, John
C. Pair Horticultural Center, Haysville, KS, 67060
Common sugar maple (Acer saccharum Marshall) selections suffer
from prolonged drought and constant wind on the southern Great
Plains. Nonirrigated plants often have scorched and torn leaves as a
result of these environmental stresses. In field studies, a sugar maple
ecotype native to western Oklahoma (known as ‘Caddo’ maple) has
shown improved tolerance to drought and leaf tatter. A study to examine drought tolerance of seedling ‘Caddo’ maple compared to typical
seedling sugar maple was established at the John C. Pair Horticultural
Center. One seedling of each type was planted in a single 38-L container.
Containers were placed on a greenhouse bench, and once acclimated,
irrigation was withheld until predawn leaf water potential indicated a
substrate water potential of –1.5 MPa. Containers were weighed, and
seedlings were maintained in a prolonged drought condition for 3 weeks
by adding water each morning to return the container to the original
weight. After 3 weeks, photosynthetic temperature response curves
were generated for the drought-stressed and the irrigated control plants.
Osmotic potential of expressed sap was also measured on rehydrated
leaves. The main effects of species, irrigation, and temperature were all
significant. ‘Caddo’ maples were able to maintain a higher rate of net
photosynthesis than the typical seedlings when drought stressed and as
temperature increased. The optimum temperature for photosynthesis did
not significantly differ among treatments (36 °C), whereas the maximum rate of photosynthesis was significantly greater for the ‘Caddo’
maples (41 μmol·m-2·s-1) than the typical sugar maples (16 μmol·m-2·s-1).
(113) Quantifying Landscape Microclimates and Related
Cold Injury
Shadd Taylor*, Derald A. Harp, Kristen McDowell, Roque Lemus
Texas A&M University-Commerce, Agricultural Sciences, Commerce, TX, 75482
(114) Effects of Planting Depth on Landscape Tree
Survival and Girdling Root Formation
Christina Wells*1, Karen Townsend2, Judy Caldwell1, Donald Ham2,
E. Thomas Smiley3, Michael Sherwood3
1
Clemson University, Horticulture, Clemson, SC, 29634; 2Clemson University, Forestry and
Natural Resources, Clemson, SC, 29634; 3Bartlett Tree Research Lab, Charlotte, NC
Landscape trees are frequently planted with their root collars below
grade, and it has been suggested that such deep planting predisposes
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(115) Soil Inoculum Potential and Mycorrhizal
Colonization of Acer rubrum in Forested and Developed
Landscapes
P. Eric Wiseman1, Christina Wells*2
1
Clemson University, Forestry and Natural Resources, Clemson, SC, 29634; 2Clemson
University, Horticulture
Arbuscular mycorrhizal fungi (AMF) form a symbiotic relationship
with numerous landscape tree species and can improve tree growth and
environmental stress tolerance. Construction-related soil disturbance is
thought to diminish AMF colonization of transplanted trees in newly
developed landscapes. We gathered root, soil, and foliar data from red
maples (Acer rubrum) growing in newly developed landscape sites
and adjacent native forest sites to test the hypotheses that: 1) landscape
trees show lower levels of AMF colonization than forest trees; and
2) the AMF inoculum potential of landscape soils is lower than that
of forest soils. Fine roots sampled from landscape maples had significantly lower AMF colonization than maples from adjacent forest sites
(3% vs. 22%; P = 0.0002). However, soil-sand mixtures made from
landscape soils possessed greater AMF inoculum potential than those
made from forest soils (10% vs. 4%; P = 0.0081). Forest soils were
more acidic and possessed less extractable P than landscape soils, and
differences in AMF colonization between forest and landscape maples
appeared to reflect differences in soil chemical properties rather than
in soil inoculum potential.
(116) Short-term Responses of Live Oak to Planting
Depth and Soil Amendments
Donita L. Bryan*1, W. Todd Watson2, Leonardo Lombardini1,
John J. Sloan3, Andrew D. Cartmill1, Geoffrey C. Denny1,
Michael A. Arnold1
1
Texas A&M University, Horticultural Sciences, College Station, TX, 77843-2133; 2Texas
A&M University, Forest Science, College Station, TX, 77843-2135; 3Texas A&M University,
Environmental Soil Science, Dallas, TX, 75252
Tree transplanting practices influence plant survival, establishment,
and subsequent landscape value. However, transplanting practices vary
substantially within the horticultural industry. Of particular importance
is the location of the root collar relative to soil grade at transplant. The
objective of this study was to determine the effects of factorial combinations of planting depths, root collar at grade or 7.6 cm either above or
below grade, and soil amendments on container-grown (11 L) Quercus
virginiana Mill. Soil treatments included a tilled native soil (heavy clay
loam, Zack Series, Zack-urban land complex, fine, montmorillonitic,
thermic, udic paleustalfs), native soils amended with 7.6 cm of coarse
blasting sand or peat that were then tilled to a depth of 23 cm, or raised
beds containing 20 cm of sandy loam soil (Silawa fine sandy loam,
siliceous, thermic, ultic haplustalfs). A significant (P ≤ 0.05) block
by soil amendment interaction occurred for photosynthetic activity.
Incorporation of peat significantly decreased the bulk density of the
native soil. Planting depth had no significant effect on photosynthetic
activity or stem xylem water potential at 3 months after transplant. Soil
water potentials did not statistically differ among treatments.
POSTERS–THURSDAY
It is generally accepted that plants closer to structures benefit from the
warmth emitted via imperfect insulation and solar energy reemitted
as long-wave, thermal radiation. However, while claims of protection
are given, little quantifiable information exists on the extent or pattern
of this protection. We studied existing plantings of Trachelospermum
asiaticum, an evergreen groundcover that is frequently damaged in
northeast Texas. The plantings studied were part of a landscape with
at least five different identifiable microclimates: 1) near building (NB);
2) mid-bed (MB); 3) bed edge (BE); 4) beneath Quercus virginiana
(LO); and 5) beneath Pyrus calleryana ‘Bradford’ (BP). We placed
HOBO temperature data loggers recording one temperature per minute
in each location. Following our first damaging freeze, we waited 7 days
before collecting leaf samples. Leaf samples were collected by using
a 25-cm square, 2 cm deep on two sides. The square was placed on
the groundcover so that the top of the groundcover was level with the
top of the square. All leaves and stems that extruded through the top
2 cm of the square were excised. Four samples were taken from each
location, and the number of damaged and nondamaged leaves were
counted for each sample. Leaves that were at least 50% discolored
were considered damaged. Leaf damage data were analyzed using SAS
Proc ANOVA. Leaves in the BE and BP locations showed significantly
fewer live leaves than any other locations. NB leaves were virtually
undamaged. Average temperatures in the BE and BP locations were
4.5 to 5 °F colder than the “near building” locations, comparable to an
a or b zone in the current USDA Plant Hardiness Zone map.
trees to transplant failure and girdling root formation. The objective of
the present research was to examine the effect of planting depth on the
health, survival, and root development of two popular landscape trees,
red maple (Acer rubrum) and ‘Yoshino’ cherry (Prunus ×yedoensis).
Trees were transplanted with their root flares at grade, 15 cm below grade
or 31 cm below grade. Deep planting had a strong negative effect on
the short-term survival of ‘Yoshino’ cherries. Two years posttransplant,
50% of the 15-cm- and 31-cm-deep planted cherries had died, whereas
all the control cherries had survived (P < 0.001; 2). Short-term survival
of maples was not affected by planting depth. Deep-planted trees of
both species exhibited little fine root regrowth into the upper soil layers
during the first year after transplant. Four years posttransplant, control
maples had 14% ± 19% of their trunk circumference encircled by girdling or potentially-girdling roots; this number rose to 48% ± 29% and
71% ± 21% for 15-cm- and 31-cm-deep planted maples, respectively
(P < 0.01; ANOVA main effect). There were no treatment-related differences in girdling root development in the cherries.
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(117) A Profile of Landscape Service Providers in West
Central Florida
Sudeep Vyapari*1, Robert J. Graves1, Edmund L. Thralls2
1
University of Florida, Environmental Horticulture, UF/IFAS, Plant City, FL, 33563;
University of Florida, Environmental Horticulture, Mid Florida Research and Education
Center, Apopka, FL, 32703
2
A survey of landscape service providers was conducted in conjunction with the 2004 Tree and Landscape Short Course in Tampa, Fla. A
greater proportion of participants (56%) provided landscape maintenance services, and 60% of the businesses were independently owned.
About 67% of the respondents indicated that their businesses were in
operation for over 10 years with 33% of the participants making one
million dollars or more in gross sales per year. Although 43% of the
respondents indicated that they served only one type of account, at least
29% of the providers served two types of accounts, and 24% served
three types. In response to various questions on a Likert scale of 1–5,
about 39% of the respondents completely agreed that word-of-mouth
is the best marketing method and 41% agreed that an attractive logo
on company trucks works as a great marketing tool. Many participants
either agreed (27%) or were neutral (27%) when asked if they thought
that the customers have no understanding of the costs involved in
providing services to them. The survey results show that 73% of the
respondents believe the most important factor that impacts and helps
retain a customer base at a steady level is quality of work performed
followed by professional employees, appearance, and knowledgeable
employees. Cheap prices or discounts offered were rated as being low
factors in retention of customers. Most service providers (31%) do not
communicate with their customers using brochures, newsletters, flyers,
emails, or websites. About 61% of service providers promote low water
use plants followed by use of Florida native plants.
Poster Session 48—Plant Biotechnology 4
21 July 2005, 12:00–12:45 p.m. Poster Hall–Ballroom E/F
(285) DNA Fingerprinting of Flowering Dogwood Cultivars
Naomi R. Smith, Robert N. Trigiano*
University of Tennessee, Entomology and Plant Pathology, Knoxville, TN, 37996-4560
Flowering dogwood (Cornus florida L.) is an important tree of forests
and urban landscapes in the eastern United States. Currently, there are
over 100 cultivars of flowering dogwood commercially available. An
identification process based on genotype would be of use to researchers,
breeders, and nurserymen, as many cultivars are similar phenotypically.
Molecular markers offer a promising way of definitively identifying
flowering dogwood cultivars. Amplified fragment length polymorphism
(AFLP) is a technique that can be used to generate DNA fingerprints.
DNA was isolated from leaves of 17 common cultivars of dogwood
and AFLP fingerprints were generated by a Beckman Coulter CEQ™
8000. Fingerprints were converted to binary data and verified manually.
Two drafts of a cultivar identification key were generated based on the
corrected, verified binary data and cultivar-specific peaks. Six primer
combinations were used to construct all keys and were tested with seven
unknown dogwood cultivar samples. Six unknown samples were correctly identified using the keys. Only one unknown, ‘Cherokee Brave’,
was unidentifiable with any key. In all cases, some intracultivar variation
was observed. A similarity index was calculated and visualized with a
tree of genetic relatedness using NTSYSpc. Intracultivar variation was
observed in the similarity index as well. This database for cultivar-specific
molecular markers will serve as a starting point to which other cultivars
can be added and also can be used in breeding applications, patent application and other projects, such as mapping the C. florida genome.
(286) Hairy Root Culture as a Source of Unique
Secondary Metabolites from Echinacea Species
Fredy R. Romero*, David J. Hannapel, Kathleen Delate
Iowa State University, Horticulture, Ames, IA, 50011
Echinacea is one of the best-selling medicinal plants in the United
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States. It was historically harvested from wild populations, but its
demand has increased so significantly that commercial production has
become a necessity to supply the increasing demand and to protect
wild populations. The medicinal properties of echinacea are associated with secondary metabolites that are produced mainly in the roots.
Hairy roots, induced by the Ri plasmid of Agrobacterium rhizogenes,
have been produced in other crops as alternative sources of secondary
metabolites that commonly are produced and synthesized in the roots
of mature plants. This method of production offers some advantages
over traditional agricultural systems, such as the possibility of producing novel compounds year-round. The overall goal of this project is to
explore the utility of hairy root cultures (mediated by A. rhizogenes) as
an efficient, alternative, and enriched source of secondary compounds
with medicinal properties, such as alkamides, flavonoids, and caffeic
acid derivatives. We have been successful in transforming roots from
E. angustifolia, E. pallida, and E. purpurea plants, and confirming the
presence of rol ABC genes in hairy roots using molecular techniques.
Roots from control plants show no active growth under dark conditions,
whereas transformed roots from E. pallida and E. purpurea show a
low degree of branching with a slow growth rate on solid media under
darkness. However, transformed E. angustifolia show a faster growth
rate and higher degree of branching under the same conditions. Currently, we are working on the optimization of the growing conditions
of the transformed roots and will proceed to the biochemical analysis
phase of the project.
(287) Chloroplast Small Subunit Rubisco Protein Is
Ingested by Migratory Endoparasitic Nematodes
Tridate Khaithong*1, Brent S. Sipes1, Adelheid R. Kuehnle2
1
University of Hawaii, Department of Plant and Environmental Protection Sciences,
Honolulu, HI, 96822; 23University of Hawaii, Department of Tropical Plant and Soil
Sciences, Honolulu, HI, 96822
Lack of a conclusive evidence of ingestion of plastid components by
plant-parasitic nematodes cautions the use of plastid transformation
technology for nematode resistance. Nematode-resistant effector
proteins generally require ingestion by the nematode to be effective.
Transgene-encoded proteins produced in plastids are not known to be
exported into the cytoplasm. Disintegration of plant cell organelles
after nematode feeding suggests that nematodes possibly ingest plastid
components. Proof of ingestion will validate the development of plastid
transformation for nematode resistance. Small subunit ribulose-1,5bisphosphate carboxylase/oxygenase (SSRubisco) protein is prevalent
in chloroplasts and thus chosen as a study molecule. The migratory
endoparasitic nematodes Pratylenchus penetrans and Radopholus
similis were cultured on green carrot callus containing chloroplasts.
Total nematode proteins were extracted and subjected to western blot
analysis using cross-reactive polyclonal antibody raised against spinach SSRubisco. Positive detection of SSRubisco occurred in protein
extracts from nematodes fed on green carrot callus, but not in extracts
from nematodes cultured on non-green alfalfa root callus as negative
control. These results confirm the ingestion of plastid components of
MW 14 kDA by migratory endoparasitic nematodes.
(288) An Arabidopsis thaliana Phytochelatin Synthase
(AtPCS1) Gene Expressed in Transgenic Indian Mustard
Contributes Partial Tolerance to Cd and Zn
Ksenija Gasic, Schuyler S. Korban*
University of Illinois, Department of Natural Resources & Environmental Sciences, 310
ERML, Urbana, IL, 61801
Phytochelatins (PCs) are heavy metal binding peptides that play
important roles in sequestration and detoxification of heavy metals in
plants. To develop transgenic plants with increased tolerance and/or
accumulation of heavy metals from soil, an Arabidopsis thaliana
FLAG–tagged AtPCS1 cDNA encoding phytochelatin synthase (PCS)
under the control of a 35S promoter was expressed in Indian mustard
(Brassica juncea). Four transgenic Indian mustard lines, designated
pc lines, with different levels of AtPCS1 mRNA accumulation and
correspondent AtPCS1 protein levels were selected and analyzed for
tolerance to cadmium (Cd) and zinc (Zn). Heavy metal tolerance was
HORTSCIENCE, VOL. 40(4), JULY 2005
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assessed by measuring root length of 10-day-old seedlings grown on
agar medium supplemented with different concentrations of Cd (0, 100,
150, and 200 μM CdCl2) and Zn (200, 400, 600, and 800 μM ZnCl2).
All transgenic lines showed significantly longer roots when grown on
a medium supplemented with 100 μM CdCl2. No significant differences
were observed between transgenic lines and wild type when plants were
grown on higher levels of Cd. This indicated that only partial tolerance
to Cd was observed in these transgenic lines. Similarly, partial tolerance
for Zn was also observed in these transgenic lines, but up to levels of
400 μM ZnCl2. Expression levels of AtPCS1 protein were not related to
tolerance responses for either Cd or Zn stresses in transgenic lines.
(289) GUS Expression in LEACO10.92kb -GUS Tobacco
Plants Suggests That Auxin and Ethylene Are Involved in
LEACO10.92kb Promoter Induction
Richard McAvoy*, Mariya Khodakovskaya, William Smith, Degang
Zhao, Hong Liu, Hui Duan, Yi Li
University of Connecticut, Department of Plant Science, Storrs, CT, 06269-4163
A 920 bp fragment of the ACC oxidase gene promoter from tomato
(LEACO1) was used to drive GUS gene expression. The LEACO10.92kb
fragment contained two stress-responsive short motifs; a 10 bp TCA
motif (5’-TCATCTTCTT-3’) twice (allowing two substitutions) and an
8 bp element (5’-AA/TTTCAAA-3’) once. The TCA motif is found in
over 30 stress- and pathogen-inducible genes while the 8 bp element is
necessary for ethylene-response in the carnation GST1 and the tomato
E4 gene promoters. Previously in chrysanthemum, cytokinin regulation
with LEACO10.92kb produced dramatic increases in lateral branching
and bud initiation. Tobacco plants carrying LEACO10.92kb–GUS were
used to examine the response of the LEACO10.92kb promoter to various
hormones and hormone inhibitors. GUS activity in LEACO10.92kb–GUS
plants was detected in leaves and stems, but not roots. High expression
was detected in shoots with the apical bud intact, but GUS activity
decreased with the apical bud removed. Applying IAA to the shoot
apex after removing the apical bud, restored GUS activity. However,
the IAA transport inhibitor TIBA reduced GUS activity in shoots with
intact apical buds, and in IAA-treated shoots with excised buds. In
shoots with excised apical buds, GUS activity increased when the
ethylene precursor ACC was applied, but decreased in intact shoots
when the ethylene biosynthesis inhibitor AOA was applied. These
data suggest that auxins produced in the apical meristem are capable
of regulating LEACO10.92kb activity, probably through auxin-induced
ethylene biosynthetic pathway activity.
Mariya Khodakovskaya1, Richard McAvoy*1, Hao Wu1,
Jeanne Peters2, Yi Li1
1
University of Connecticut, Department of Plant Science, Storrs, CT, 06269-4163; 2Rutgers
University, Department of Plant Biology & Pathology
Chill injury and leaf senescence occur in plants held in prolonged cold,
dark storage. To increase tolerance to these conditions, Nicotiana alata
and N. tabacum were transformed with either the FAD7 or IPT genes
under the control of a cold-inducible promoter (cor15a). FAD7 encodes
for omega-3-fatty acid desaturase and was used to resist cold-stress.
IPT encodes the cytokinin-pathway enzyme isopentenyl transferase
and was used to delay senescence. Independent FAD7 and IPT lines
were crossed to produce double transgenic seed. Seedlings from single
transgenic (cor15a-IPT or cor15a-FAD7) lines, double transgenic lines,
and the wild-type were exposed to prolonged cold, dark conditions.
After 3 months in the dark at 2 °C, survival of independent double
transgenic N. tabacum lines ranged up to 80% to 90%. However only
40% of FAD7 seedlings survived, 10% of IPT seedlings survived, and
no wild-type plants survived. Double transgenic N. alata seedlings
average 90% survival under similar conditions and RT-PCR revealed
expression of both the IPT and FAD7 genes. Omega-3-FAD enzyme activity increases desaturation in chloroplast membrane fatty acids. When
exposed to prolonged cold, the molecular fraction of polyunsaturated
fatty acids (18:3 and 16:3) in leaves of wild-type N. alata decreased
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(291) Adventitious Shoot Production and Transformation
of Euonymus alata
Alan G. Smith*, Elizabeth S. Zimmermann
University of Minnesota, Horticultural Science, Saint Paul, MN, 55108
Euonymus alata is an attractive landscape plant that has been reported
to be an invasive species. Genetic modification through transformation
is a method of reducing its invasiveness by producing sterile cultivars
having limited or no seed production. A critical step in Agrobacteriummediated gene transfer is the production of adventitious shoots. E. alata
internodes and leaves from in vitro cultures were tested for adventitious
shoot production on 16 plant growth regulator combinations: four
levels of 6-benzylamino purine (BA) and three auxin treatments [0.5
or 0.25 mg·L-1 indole-3-butyric acid and 0.1 mg·L-1 naphthaleneacetic
acid (NAA)], as well as no auxin. The optimal BA levels were found
to be 0.5 or 1.0 mg·L-1 for maximizing the number of explants forming
shoots and for producing the greatest number of shoots per explant.
Culturing on NAA gave the greatest number of shoots per explant
with both 0.5 and 1.0 mg·L-1 BA. Shoot production from internode
segments was markedly superior to leaves. An initial dark treatment of
10 days did not influence shoot production. Using 1.0 mg BA with 0.1
mg·L-1 NAA, E. alata internodes were transformed with A. tumefaciens
EHA105 carrying Kanamycin resistance and β-glucuronidase genes.
Transformed shoots were selected on 30 mg·L-1 Kanamycin. Of the
36 shoots produced, 16 were confirmed to be transformed by β-glucuronidase histochemistry. Treatment with rooting powder containing
indole-3-butyric acid did not aid rooting of shoots, but after 3 months
in soil in high humidity, 21 of 24 E. alata shoots from tissue culture
were rooted and acclimated.
(292) In Vitro Rooting of Bigtooth Maple Microshoots
Clare Bowen-O’Connor1, John Hubstenberger1, Dawn VanLeeuwen2,
Rolston St. Hilaire*1
1
New Mexico State University, Agronomy and Horticulture; 2New Mexico State University,
Agricultural Biometric Service
Double-node microshoots of bigtooth maple (Acer grandidentatum
Nutt.) were rooted in vitro on Driver-Kuniyuki Walnut (DKW) tissue
culture media containing indole acetic acid (IAA). Microshoots represented six sources from three locations within Texas and New Mexico.
Microshoots were placed in Phytatrays II™ containing DKW media with
no plant growth regulator (DKW0) to reduce the high cytokinin levels
used for shoot proliferation. Microshoots were induced to form roots
for 15 days by placing them on DKW media containing IAA at 0.01,
1, 2.5, 5, 10, 15 or 20 μmol. Rooting frequency, the number of leaves
and callus area were recorded every 30 days for 60 days. Rooting frequency increased up to 29% as IAA concentration increased (P = 0.004).
However, as much as 71% of shoots for one of the three Guadalupe
Mountain, Texas, sources rooted without auxin treatment after 30 days.
The IAA concentration also affected the number of leaves per shoot
(P = 0.0228) which averaged seven and callus area (P = <0.0001) which
averaged 52 mm2. Average leaf size was 307 mm2. We conclude that
IAA induces rooting in microshoots of bigtooth maple after 15 days of
root induction. However, one source rooted without auxin treatment.
The presence of callus does not interfere with root formation.
POSTERS–THURSDAY
(290) Increased Tolerance to Dark, Cold Storage in
Double Transgenic Plants Expressing FAD7 and IPT
Genes under the Control of a Cold-inducible Promoter
while monounsaturated (16:1 and 18:1) and saturated fatty acid species
(16:0 and 18:0) increased dramatically. In double transgenic N. alata
lines exposed to prolonged cold, the molecular fraction of 18:3 and
16:3 increased, while the 16:0 and 18:0 species decreased dramatically
compared to nonchilled double transgenic plants.
(293) Single Nucleotide Polymorphism in matK and
Ribosomal ITS of Astilbe
Brian W. Trader*, Richard E. Veilleux, Holly L. Scoggins
Virginia Tech, Horticulture, Blacksburg, VA, 24061
The genus Astilbe (Saxifragaceae) comprises about 13 species and is
ranked consistently among the top 10 landscape perennials. Through
extensive hybridization, selection and marketing, the lineage of many
Astilbe has been lost. Subdioecious Astilbe biternata is the only species
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in the genus native to North America while other members of the genus
are endemic to Asia and monoecious. Due to the unusual geographic
distribution of the species and the variation in floral development
among them, development of genetic markers using single nucleotide
polymorphisms (SNPs) would confirm phylogenetic relationships
and establish lineage within the genus. Astilbe species, hybrids, and
cultivars were obtained from plant nurseries and botanical gardens
across the country. To elucidate relationships among the genus, we
conducted phylogenetic analysis of DNA sequences of the chloroplast
gene matK and the internal transcriber spacer (ITS) of ribosomal rDNA
genes. DNA was extracted, and gene primers trnK3914 and trnK2R
were used to amplify matK, and primers 1406F and ITS2 were used
to amplify the ITS1 region between 18S and 5.8S ribosomal DNA
units. Both matK and ITS were sequenced for each plant specimen
and sequences were aligned to identify nucleotide diversity and detect
SNPs. Variation in nucleotide sequence for either gene yielded similar
dendrograms. Nucleotide variation among the Astilbe utilized in this
study has allowed the development of SNP markers that may be useful
for fingerprinting unknown hybrids or cultivars in the industry, and
may be used for species alignment within the genus.
phenomenon. In order to determine the compatibility/incompatibility
between Sapotaceae species, heterograftings were made using the
mamey [Calocarpum sapota (Jacq.) Merr.] as scion, and chicozapote
[(Achras sapota (L.)] was used as rootstock. Grafting was conducted
during the phenological stage of defoliation of the scion donor plant,
as well as during budding. Homografts were also made using C. sapota on C. sapota in both phenological stages. Plant tissue samples
were obtained from scions and rootstocks in both phenological stages,
and they were used for HPLC analysis. Heterografts (C. sapota on
A. sapota) showed 100% incompatibility in both stages, and lack of
success during grafting was obtained; similar results were registered
with the homografts (C. sapota on C. sapota) during the budding stage;
however, during the defoliation stage, 80% successful grafting was
obtained. The responsible substances involved in the phenomenon of
compatibility/incompatibility using samples taken during the grafting
day and 60 days after (C. sapota grafted on A. sapota during defoliation stage), were identified as catechin and epicatechin. Catechins are
the responsible substances of incompatibility in the heterografts of C.
sapota/A. sapota in both phenological stages, as well as during the
budding stage in the homografts on C. sapota.
Poster Session 49—Tropical Horticulture/Working Group
(443) International Conference on Vegetables: ICV–2002
Prem Nath*1, Sundari Velu2
of Asian Horticulture
1
21 July 2005, 1:15–2:00 p.m.
Poster Hall–Ballroom E/F
(441) Evaluation of Three Grafting Methods for
Propagating Soursop (Annona muricata L.) in the Dry
Tropic Region of Mexico
Juan Manuel González Gonzalez*, Francisco Radillo Juarez,
Marcelino Bazan Tene, Juan Carlos González Ramos
Universidad De Colima, Facultad de Ciencias Biológicas y Agropecuarias, Tecomán,
Colima, 28100, México
Soursop (Annona muricata L.) is reproduced by seeds from ‘Criollo’
cultivars in Mexico. The replication of desirable agronomic traits
is difficult when selected plants are from sexual reproduction. The
heterogeneity of plants is observed as taller trees, irregular fresh fruit
yield, variable fruit quality, different insect pests, disease susceptibilities, and lower number of plants per hectare. There is an extended time
period for recovering investments and commericialization problems
due to fruit quality and price. Vegetative propagation is an alternative
for reducing the heterogeneity of soursop trees. Three grafting methods were evaluated for propagating soursop in the dry tropic region
of Colima, Mexico: 1) splice side graft; 2) wedge graft; and 3) bud
graft. The experiment was carried out on the Tecoman Campus of the
Universidad de Colima. Rootstocks were from 8-month-old healthy
plants, 1-m tall and 1-cm diameter, obtained from ‘Criollo’ seedlings,
and the scions were obtained from a healthy 10-year-old ‘Sin Fibra’
donor tree. This donor tree was selected for its excellent agronomic traits
and fruit yield. Vigorous and terminal scions were used, disinfected
with fungicide, and used the same day of excision. The experiment
was distributed under a completely randomized design. Splice side
grafting had 67% success after 60 days, while wedge grafting and bud
grafting had 0% success.
(442) Catechins and Compatibility in Calocarpum sapota
(Jacq.) Merr. Homografts and Calocarpum sapota on Achras
sapota (L.) Heterografts during Two Phenological Stages
Juan Manuel González Gonzalez*, Oscar Rebolledo Dominguez,
Lourdes Diaz Jimenes
Universidad de Colima, Facultad de Ciencias Biológicas y Agropecuarias, Tecomán,
Colima, 28100, México
The responsible substances involved in the phenomenon of compability/incompatibility in Sapotaceae species during two phenological
stages were elucidated. An experiment was carried out to determine
the compatibility/incompatibility relationship between homografts
and heterografts of Sapotaceae species during two phenological
stages, and to identify the responsible substances involved in the
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Dr. P.N. Agricultural Science Foundation (PNASF), Chairman, #9, Bangalore, Karnataka,
560 094, India; 2Dr. P.N. Agricultural Science Foundation (PNASF), Technical Advisor,
Irvine, CA, 92620-2717
In a world that produces enough food for everyone, about 800 million people in the developing world do not have enough to eat. The
important challenge facing agriculture in the new millennium is to
eliminate chronic hunger. Safe and better quality food is equally
important to ensure that people not only have sufficient energy but
also the nutrients necessary for adequate productive lives. In order to
release the pressure on cereals as well as to improve human nutrition
through consumption of the other nutritious crops, diversification in
cropping patterns provides better options, and horticultural crops, including vegetables with their wide adoption and providers of important
nutrients, offer promise for the future. In this spirit and in the wake of
the present global call for eliminating food and nutritional insecurity,
the technologists, entrepreneurs, policy-makers and those interested in
agriculture were invited to participate and contribute to fruitful discussion at the International Conference on Vegetables (ICV–2002), which
was held 11–14 Nov. 2002 in Bangalore, India. About 700 participants
from 37 countries across the globe participated in the conference,
and a total of 621 papers were presented. The ICV–2002 addressed
13 theme areas, which included vegetable improvement in production, protection, underutilized vegetables, postharvest management,
developmental policies and programs, marketing and trade including
WTO policies and programs, and, finally, technical cooperation among
developing countries. The salient recommendations of the ICV–2002
will be presented.
(444) Management Practices to Improve Yield of Camellia
oleifera Abel
Jiangfan Yu*
Central South Forestry University, School of Resource and Environment, Changsha,
Hunan, 410004, China
Oil-tea plant (Camellia oleifera Abel), one of the four woody plants
that produce edible oil for human consumption, is widely cultivated in
Jiangxi Province (China) with production areas of 834,000 ha. Under
conventional cultivation techniques, the oil yield of oil-tea plant was
only 30 to 45 kg·ha-1, which significantly limited its economic impact
and development. In the past 10 years, management practical techniques,
such as preparing soil with organic fertilizer, weed control, thinning,
pruning, alternated harvest time, improved harvest techniques, etc., had
been implemented to replace traditional practices. Also, some new and
promised clones were used to reforest and regenerate some areas with
aged and degraded Camellia oleifera plantations. The results indicated
that the new plantations and regenerated forests produced fruits for
refining oil in their third year. The yield was significantly higher than
that of the original stands in their fourth year and reached 712.5 kg·ha-1
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in their sixth year. The highest yield, 750 kg·ha-1, was harvested at their
eighth year after the new management practices. Oil-tea plant is not a
low-yield and low-valued crop and the average yield could improve
6–7 times per hectare with selected clones and proper management.
Both management practices and clone selection are key issues to the
yield of oil-tea plant plantations. Best management techniques and
better clones have been applied by the farmers today and the goal is to
reforest or regenerate 80% of the production areas in Jiangxi Province.
Future studies will focus on breeding better cultivars under these new
management practices.
Poster Session 50—Pomology–Physiology/Plant Growth
Regulators
21 July 2005, 1:15–2:00 p.m.
Poster Hall–Ballroom E/F
(333) Floral Commitment and Morphogenesis in Ten
Apple Cultivars
Jianying Peng1, Peter Hirst*2
1
Agricultural University of Hebei, College of Horticulture, Baoding, Hebei, 071001,
China; 2Purdue University, Department of Horticulture and Landscape Architecture, West
Lafayette, IN, 47907-2010
Buds were sampled from nonflowering spurs on 1-year-old wood of
10 apple cultivars during the 2004 growing season and dissected to
determine floral commitment and morphogenesis. Dissected buds
were classified into five stages based on floral bud morphogenesis.
The 10 cultivars differed in their patterns of floral commitment and
morphogenesis. At the end of the growing season, the proportion of
floral buds was 30% to 100% depending on cultivar. The probability
of observing doming, indicating floral commitment, was from 5% to
50% depending on cultivar, with ‘NJ90’ (50%), ‘Zestar’ (30%), and
‘CQR10T17’ (30%) rated among the highest. The lowest probability
(5%) was with ‘Ambrosia’, ‘Pinova’, and ‘Silken’. The time of a peak
of floral commitment was earliest in ‘Delblush’ and ‘CQR10T17’ and
latest in ‘Sundance’™ and ‘Pinova’. Most cultivars exhibited a single
peak of floral commitment, except for ‘Pink Lady’ in which two peaks
were present. The duration of the process of flower initiation was from
20 to 43 days depending on cultivar. The timing of floral commitment
and morphogenesis was not related either to blooming date, or to fruit
harvest time of the cultivar.
Guohai Xia, Lailiang Cheng*
Cornell University, Horticulture, Ithaca, NY, 14853
Four-year-old ‘Gala’/M.26 trees were grown under low (2.5 mM),
medium (12.5 mM), or high (25 mM) N supply with balanced nutrients
in sand culture and the cropload was adjusted to 5 fruit/cm2 trunk
cross-sectional area at 10 mm king fruit. After harvesting, half of the
trees in each N treatment were sprayed twice with 3% urea a week
apart in late September. Before budbreak the following spring, four
trees from each treatment combination were destructively sampled for
reserve nitrogen and carbohydrate analysis. Foliar urea application
significantly increased tree N concentration and concentrations of both
free amino acids and proteins, but decreased the concentration of total
nonstructural carbohydrates (TNC) at each soil N supply level. When
the carbon in free amino acids and proteins are taken into account,
trees sprayed with foliar urea had similar levels of total sum of carbon
in TNC, free amino acids and proteins. On a whole tree basis, trees
sprayed with foliar urea had more N and less TNC. During the second
year of the experiment, all the trees received normal N supply. Trees
sprayed with foliar urea the previous fall had a significantly larger total
leaf area and higher fruit set, fruit number, and total yield than those
unsprayed. We conclude that fruit set and early fruit development as
well as vegetative growth in spring is mainly determined by reserve
nitrogen, not by reserve carbohydrates. Conversion of a portion of
TNC to amino acids and proteins leads to better growth and fruiting
of apple trees.
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Rui Zhou, Lailiang Cheng*
Cornell University, Horticulture, Ithaca, NY, 14853
Apple leaf ADP-glucose pyrophosphorylase was purified over 1400fold to apparent homogeneity with a specific activity of 58.9 units
per mg of protein. The enzyme was activated by 3-phosphoglycerate
(PGA) and inhibited by inorganic phosphate (Pi) in the ADPG synthesis direction. In the pyrophosphorolysis direction, however, high
concentrations of PGA (>2.5 mM) inhibited the enzyme activity. The
enzyme was resistant to thermal inactivation with a T0.5 (temperature
at which 50% of the enzyme activity is lost after 5 min of incubation)
of 52 °C. Incubation with 2 mM PGA or 2 mM Pi increased T0.5 to 68
°C. Incubation with 2 mM dithiothreitol (DTT) decreased T0.5 to 42
°C, whereas inclusion of 2 mM PGA in the DTT incubation maintained
T0.5 at 52 °C. DTT-induced decrease in thermal stability was accompanied by monomerization of the small subunits. Presence of PGA
in the DTT incubation did not alter the monomerization of the small
subunits of the enzyme induced by DTT. These findings indicate that
the binding of PGA may have dual functions in regulating apple leaf
AGPase activity—activating the enzyme and rendering the enzyme
with a conformation more stable to thermal inactivation.
(336) Temperature Effect on Seasonal Growth of Pear
Fruit
Patricia Garriz*, Hugo Alvarez, Graciela Colavita
Comahue National University, Applied Biology, c.c. 85, Cinco Saltos, Rio Negro, 8303,
Argentina
Temperature has long been recognized as a major environmental
factor affecting the net carbon exchange in the pear tree, as well as the
growth of fruit. The objective of this work was to predict pear fruit
growth as a function of accumulated growing-degree-days (DD) using
a mathematical model. A crop of ‘Abbé Fetel’ trees was studied at the
Experimental Farm of the Comahue National University, Argentina
(lat. 38°56’S; long. 67°59’W). Maximum fruit diameter (FD) measurements were carried out every 2 weeks during three growing seasons
(2000–01, 2001–-02, and 2002–03). The range of sampling dates
was 26 and 143 days after full bloom (DFB). An automated meteorological station, situated close to the orchard, collected temperature
data, which were expressed on the basis of DD from time of full
bloom to harvest, with critical temperatures at 4 and 35 °C. Equations were developed with SYSTAT procedure and model suitability
was evaluated using goodness-to-fit measures. It was found that the
following logistic regression provided the most satisfactory fit
for the pooled data: FD (mm) = 71.62/[(1 + e∧(1.7450-0.0027DD)],
coefficient of determination = 0.96. The testing on an independent
crop showed that predictions were accurate. Analyses of fruit growth,
based on DD, did not improve data interpretation over that on a DFB
basis. The average monthly temperature varied little between seasons. A remarkably consistent heat-unit accumulation function was
obtained from year to year, with a 5% maximum variation in number
of DFB to maturity, compared to a 6% variation in DD, occurring
between the 2002 and 2003 commercial harvests. These results have
important implications for cultural practices, such as fruit thinning
and final size forecast.
POSTERS–THURSDAY
(334) Fruit Set and Yield in Relation to Reserve Nitrogen
and Reserve Carbohydrates in ‘Gala’ Apple Trees
(335) Purification and Characterization of ADP-glucose
Pyrophosphorylase from Apple Leaves
(337) Effect of Selenium Supply by Trunk Injection on
Fruit Quality of ‘Niitaka’ Asian Pear
Wol-Soo Kim*, Jung-An Jo, Soon-Ju Chung
Chonnam National University, Department of Horticulture, 300 Yongbong-dong, Gwangju,
500-757, Korea
Many trials to supply selenium to fruit have been carried out since
tests have confirmed selenium’s role as a medical substance. Supplying
selenium in orchards by soil and foliar application was not effective
because of loss from rainfall. In order to increase selenium absorption
by fruit, this study carried out tree trunk injections during the growing season. Selenium solutions in concentrations of 5, 10, 25, and 50
mg·L–1 were supplied to ‘Niitaka’ pear (Pyrus pyrifolia) trees by trunk
injection (1.5 L/tree) four times at 15-day intervals from June 2004.
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The treatment with 50 mg·L–1 selenium showed necrosis symptoms
at leaf-margins after secondary treatment and toxicity as abnormally
red fruit skin color. Fruit weight and leaf area were decreased by
selenium treatments, while severe symptoms appeared with higher
selenium concentrations. Hunter values ‘a’ and ‘b’ in fruit skin color
were increased by selenium treatment in comparison to the control.
The selenium treatment showed lower soluble solids by as much as
1.2%, and higher fruit firmness. Selenium concentration in pear fruit
was increased by trunk injection with a 5 mg·L–1 solution. The bound
selenium in pear fruit after 3 months of storage in cold room conditions
was very high, but free selenium was low.
(338) Effect of Germanium Supply by Trunk Injection on
Tree Growth and Fruit Quality of ‘Niitaka’ Asian Pear
(Pyrus pyrifolia)
Wol-Soo Kim*, Jung-An Jo
Chonnam National University, Department of Horticulture, 300 Yongbong-dong, Gwangju,
500-757, Korea
Many trials to supply germanium to fruit have been carried out since
tests have confirmed germanium’s role as a medical substance. Supplying germanium in orchards by soil and foliar application was not
effective because of loss from rainfall. In order to increase germanium
absorption by fruit, this study carried out tree trunk injections during
the growing season. Two types of germanium, GeO (inorganic type)
and Ge-132 (organic type), in concentrations of 5, 10, 25, and 50
mg·L–1 were supplied to ‘Niitaka’ pear trees by trunk injection (1.5
L/tree), four times at 15-day intervals from June 2004. The treatment
with 50 mg·L–1 GeO showed decreased fruit weight, but 50 mg·L–1
Ge-132 showed no difference to the control and other treatments.
Fruit lenticels were increased in size by all of the Ge treatments in
comparison to control fruit. Soluble solids as well as Hunter value ‘a’
of the fruits of all Ge treatments were higher than that of the control.
Flesh browning after peeling the fruit was delayed by the germanium
treatment, and polyphenoloxidase (PPO) activities were lowered.
Postharvest potentials were maintained at high levels for fruit firmness, physiological disorders, and decayed fruit during cold storage
at 0 to 1 °C for 2 months.
Poster Session 51—Floriculture Nutrition and Substrates
21 July 2005, 1:15–2:00 p.m.
Poster Hall–Ballroom E/F
(119) Celosia argentea Can Be Produced Using Saline
Wastewaters
Christy T. Carter, Catherine M. Grieve, James A. Poss*
USDA–ARS, George E. Brown, Jr. Salinity Laboratory, Plant Sciences, Riverside, CA,
92507
Salinity tolerance of two cultivars of Celosia argentea (‘Chief Rose’ and
‘Chief Gold’) was investigated using a completely randomized design
with three replications. Seedlings grown in greenhouse sand tanks were
exposed to six salinity levels (2.5, 4, 6, 8, 10, and 12 dS·m–1) and two
water ionic compositions mimicking sea water and drainage waters
from the Imperial and Coachella valleys. Phenotypic measurements were
made when plants were harvested during flowering, and concentrations
of Ca2+, Mg2+, Na+, K+, Cl-, total-S, and total-P were also determined from
leaf tissues. Overall, phenotypic measurements (including stem length,
stem weight, stem diameter, inflorescence length, inflorescence weight,
and number of leaves) tended to decrease as salinity increased, yet stem
lengths were still above the minimum stem length recommended for
marketability (41 cm). Significant interactions were found for salinity
and water ionic composition for all mineral analyses for both cultivars.
As salinity increased, Ca2+, K+, and total-P decreased as Mg2+, Na+, and
Cl- increased for both cultivars. ‘Chief Gold’ can be produced commercially in either water composition up to 12 dS·m–1. ‘Chief Rose’ can
be produced up to 8 dS·m–1 in sea water and 10 dS·m–1 in water ionic
compositions similar to those of the Imperial and Coachella valleys.
Saline waters dominated by chloride and sulphate salts can be used to
produce Celosia argentea commercially.
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(120) Response of Ornamental Sunflower to Irrigation
with Saline Wastewaters
Catherine M. Grieve*, James A. Poss, John H. Draper
USDA–ARS George E. Brown Jr. Salinity Laboratory, Plant Sciences, Riverside, CA, 92507
To explore the possibility that saline wastewaters may be used to grow
high value floriculture crops, the effects of salinity were tested on Helianthus annuus (L.). Sunflower cultivars Sunbeam and Moonbright
were grown in 30 greenhouse sand tanks and irrigated initially with
nutrient solution. One week after planting, saline treatments were
imposed with solutions differing in ion composition. Fifteen tanks
were irrigated with waters typical of agricultural wastewaters present in the San Joaquin Valley (SJV) and 15 tanks were irrigated with
water compositions similar to saline tailwaters found in the Imperial
and Coachella valleys (ICV). Five treatments of each salinity type
were used with electrical conductivities (EC) of 2.5, 5, 10, 15, and 20
dS·m–1. Length of the flowering stems was significantly reduced as
salinity rose to 20 dS·m–1. Reduction was more pronounced when the
plants were irrigated with the sodium-sulfate dominated waters of SJV
composition. Flower diameter was reduced when the EC of SJV waters
exceeded 15 dS·m–1, but was not affected by any treatment when ICV
waters were used. Salt tolerance in sunflower appears to be associated
with mechanism(s) that regulate transport of potentially injurious ions.
Both Na+ and Cl- were partitioned to the lowest portion of the stem,
and effectively excluded from the remainder of the shoot. This study
illustrates that saline waters with EC = 15 or 20 dS·m–1 may be used
to produce ornamental sunflowers without significant loss of quality.
Salt stress also provides an environmentally friendly alternative to the
use of growth regulators for the control of plant height.
(121) Matthiola incana as a Model Crop for Recycling
Greenhouse Effluents
James A. Poss*, Christy T. Carter, Catherine M. Grieve,
Peter J. Shouse
USDA–ARS, George E. Brown, Jr. Salinity Laboratory, Plant Sciences, Riverside, CA,
92507
Common stock flower production can be achieved under moderate
levels of salinity and relatively low levels of nitrogen with no significant
decrease in quality in a closed-recirculating irrigation system. A 4 × 4
factorial design with partial replication was used to assess the effects
of salinity and nitrogen on the production of Matthiola incana (L.).
Seeds were sown in outdoor volumetric lysimeters at the George E.
Brown, Jr., Salinity Laboratory in Riverside, Calif., with target electrical
conductivity (EC) levels of 2, 5, 8, and 11 dS·m–1 combined with four
nitrogen treatments of 35, 50, 75, and 100 ppm N. An empirical model
was implemented to evaluate the growth response of each combination
of salinity and nitrogen treatments over the course of plant development. The three-phase model is represented by an initial size parameter
(alpha), an estimation of the intrinsic growth rate of the exponential
phase (beta), a transitional phase between the first two phases (tl), the
length of the linear phase (epsilon), and the final intrinsic saturation
rate (gamma), The model successfully fitted the plant height data over
time for all 16 nitrogen and salinity treatment combinations. Effects of
salinity on epsilon and t2 (epsilon + t1) were nonsignificant. Nitrogen
treatments had no significant effect on any of the model parameters
and the effect of salinity was greatest when irrigation water EC was 11
dS·m–1. The length of the flower-bearing stems exceeded the standards
recommended for commercial acceptability in all treatments (>41 cm).
If 60 cm is the minimum length acceptable, then 50 ppm N or more
where the EC was 8 dS·m–1 or less is required. Nitrogen uptake per unit
evapotranspiration increased with salinity and nitrogen.
(122) Simulation of Poor Quality Irrigation Waters
in Subirrigation and Top-watering using Mixture
Experiments
Matthew W. Kent, David W. Reed*
Texas A&M University, Dept of Horticultural Sciences, College Station, TX, 77843-2133
The effects of cations vs. anions in salinity studies cannot be separated
by traditional means. Analysis of mixture experiments allows ionic ef-
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fects to be analyzed individually by varying proportions of ions without
changing their total concentrations. A series of mixture experiments
were performed in the greenhouse to determine the effects of the anions
bicarbonate, chloride, and sulfate, given a constant and equal concentration of the cation sodium, on vinca ‘Pacifica Red’ grown with different
irrigation systems and leaching fractions. In subirrigation, increasing
total ion concentrations from 30 to 60 meq/L total ion concentrations
(TIC) caused a general decrease in shoot fresh and dry weights, with
bicarbonate contributing to the greatest degree of reduction, and sulfate
the least. Root dry weight was similarly decreased with increasing TIC,
but the differences between individual ion effects were more subtle.
SPAD data, an indication of chlorophyll concentration, showed a sharp
decrease with increase in bicarbonate, but not with sulfate or chloride.
Medium pH increased as TIC increased, being influenced primarily by
bicarbonate. Conversely, growing medium EC was influenced most by
sulfate and chloride, and least by bicarbonate with increasing TIC. At 30
meq/L TIC, top-watered treatments with a leaching fraction (LF) of 5%
generally had reduced shoot and root dry weight without regard to ion
species, while a leaching fraction of 35% produced results more similar
to those of subirrigation. While medium EC and pH varied with layer and
irrigation method, bicarbonate generally affected EC least and pH most.
(123) Correlation between Tissue and Substrate Silicon
Content of Greenhouse-produced Helianthus annuus
‘Ring of Fire’
Sophia Kamenidou*, Todd Cavins
1
Oklahoma State University, Horticulture and Landscape Architecture Dept., Stillwater,
OK, 74078
(124) Tuber Production of Sandersonia aurantica
Grown in a Soilless Medium Affected by the Medium
Composition and Harvesting Time
Su-Jeong Kim, Chun-Woo Nam, Dong-Lim Yoo, Jong-Taek Suh,
Myoung-Rae Cho, Ki-Sun Kim*
National Institute of Highland Agriculture, Horticulture, 3-ri, Hyonggye, Doam-yeon,
Pyeongchang-gun, Gangwon-do, 232-955, S. Korea
This study was conducted to overcome the problems occurring in soil
cultured Sandersonia, such as secondary tuber formation, tuber russeting,
browning and surface cracking. For the tuber production, soilless culture
medium compositions (peatmoss, perlite, cocopeat) and harvesting times
[4, 6, 8, 10, and 12 weeks after flowering time (WAF)] were compared.
The mother tubers were planted and grown in a plastic box (40 × 60 ×
23 cm) under a PE film house with shading in summer season. The tuber
number and weight were higher in peatmoss-based media of peatmoss,
1 peatmoss : 1 perlite, and 2 peatmoss : 1 perlite (by volume) than in the
other media. Particularly, the plant height and the numbers of leaf and
flower were also higher. The contents of total nitrogen and phosphorus
in leaves were lower when the tubers were grown in perlite. Leaf area
index per plant reached the maximum at 8 WAF and decreased thereafter. The optimal harvesting time for tuber production was 8-10 WAF.
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Ka Yeon Jeong*1, Claudio Pasian1, David Tay2
1
The Ohio State University, Horticulture and Crop Science, Columbus, OH, 43210; 2The
Ohio State University, Ornamental Plant Germplasm Center, Columbus, OH, 43210
Substrate pH of soilless media directly affects nutrient availability. Limited information about the effect of substrate pH on growth of begonia
species (not cultivated hybrids) was found in the literature. The objective
of this study was to evaluate the effect of substrate pH on the growth and
quality of six begonia species grown from June to Aug. 2004. The targeted
pH ranges (<4.5, 4.5~5.0, 5.0~5.5, 5.5~6.0, 6.0~6.5, 6.5~7.0, and over
7.0) of the peat-based substrates were obtained by adding seven different
amounts of dolomitic hydrated lime: 0, 1.0, 1.3, 1.6, 2.0, 2.4, and 2.6
kg·m3. Begonia albopicta, B. cucullata var. cucullata, B. echinosepala
var. elongatifolia, B. holtonis, B. fuchsioides (red), and B. fuchsioides
(pink), were propagated by stem cuttings, and then transplanted into
plastic containers. This experiment was a factorial experiment arranged
in a randomized complete-block design. The pH was monitored weekly
using the pour-through method and adjusted accordingly by adding flowable lime or a mild sulfuric acid solution. The pH values were averaged
for each treatment of each species. There were significant differences
between species in the inflorescence number and SPAD readings, but no
interaction between species and substrate pH was found. Stem length,
leaf area, and dry weight of each plant were significantly affected by
species and substrate pH. B. albopicta performed best at substrate pH
of 5.6 and 6.0, showing no symptoms of phytotoxicity. B. cucullata,
above substrate pH 6.0, and B. holtonis at pH 5.0 and 5.6 had the highest
vegetative growth and plant quality. Plant mortality was observed for B.
cucullata and B. fuchsioides (red) at pH below 4.4 and 5.3, respectively.
(126) Response of Six Begonia Species to Different
Substrate EC
Ka Yeon Jeong*1, Claudio Pasian1, David Tay2
1
The Ohio State University, Horticulture and Crop Science, Columbus, OH, 43210; 2The
Ohio State University, Ornamental Plant Germplasm Center, Columbus, OH, 43210
There is limited information on optimal substrate EC level for begonia
species (noncultivated hybrids). The objective of this study was to evaluate the response of six species to different substrate EC in a greenhouse.
Begonia albopicta, B. cucullata var. cucullata, B. echinosepala var.
elongatifolia, B. holtonis, B. fuchsioides (red) and B. fuchsioides (pink)
plants were propagated by stem cuttings, and transplanted into plastic
pots using a soilless mix. Five concentrations (20, 80, 200, 400, and
600 mg·L-1 N) of 17–5–17 fertilizer were applied as irrigation water
to derive the five substrate EC levels. This experiment was a factorial randomized complete-block design. Substrate EC was measured
weekly using the PourThru method and averaged for each treatment
of each species. Inflorescence number, the longest stem length, SPAD
readings, leaf area, and dry weight of each plant were measured as
growth parameters. There were significant responses to substrate EC
level and species on begonia growth parameters. The highest growth
parameters of B. albopicta and B. cucullata were obtained at EC 5.7
and 6.6 mS·cm-1, respectively. The maximum growth of B. echinosepala
and B. holtonis was observed at 2.6 and 3.0 mS·cm-1, respectively. B.
fuchsioides, grown at 1.2 mS·cm-1, had the best growth parameter values.
As EC level increased, SPAD value for B. fuchsioides (pink) and B.
holtonis also increased. The highest SPAD reading was observed at EC
3.7 mS·cm-1 for B. albopicta, EC 6.6 mS·cm-1 for B. cucullata, EC 2.6
mS·cm-1 for B. echinosepala, and EC 4.1 mS·cm-1 for B. fuchsioides
(red). Plant mortality of several begonia species was observed when
grown at EC value above 6.4 or below 4.4 mS·cm-1.
POSTERS–THURSDAY
Silicon (Si) is a beneficial element to many agricultural crops. We
found improved horticultural traits in our preliminary Si supplementation research on floricultural greenhouse crops produced in soilless
substrates. The objective of this study was to establish optimum Si rates
based on previous results and investigate the relationship of Si tissue
and substrate content. Potassium silicate (KSiO3) weekly drenches (0,
50, 100, 150 mg·L-1 SiO2), media-incorporated KSiO3 flakes (0, 280,
400, 520 g·m-3 SiO2), and ashed rice hulls (0, 200, 270, 360 g·m-3 SiO2)
were provided to Helianthus annuus ‘Ring of Fire’. Leaf, stem, and
flower tissues as well as soilless substrate samples were collected for Si
analysis. Several Si treatments resulted in plants with increased flower
and stem diameter compared to untreated controls (P ≤ 0.05). Weekly
drenches with KSiO3 (150 mg·L-1 SiO2), KSiO3 flakes (280 g·m-3 SiO2),
and ashed rice hulls (360 g·m-3 SiO2) were the most efficient treatments
based on the increased quality characteristics. Leaf tissue had the highest
Si content, followed by flower, then stem tissue. Correlation analysis
indicated that leaf and flower Si content was positively correlated with
saturated media extract substrate samples (correlation coefficients
r = 0.75 and 0.63, respectively).
(125) Response of Six Begonia Species to Different
Substrate pH
(127) Effects of Substrate on Nutrient Uptake and Nitrate
Leaching in Lilies
Donald J. Merhaut*1, Julie P. Newman2
1
University of California, Riverside, Botany and Plant Sciences, Riverside, CA, 92521;
University of California, Cooperative Extension, Ventura, CA, 93003
2
Lilies are produced throughout the year in coastal areas of California.
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Cultural practices involve daily applications of water and fertilizer,
using both controlled release fertilizers (CRF) and liquid fertilizers
(LF). However, many production facilities are in proximity to coastal
wetlands and are therefore at greater risk of causing nitrogen pollution via runoff and leaching. Due to federal and state regulations,
nurseries must present a plan of best management practices (BMPs)
to mitigate nutrient runoff and leaching and begin implementing these
practices in the next 2 years. In the following studies, we determined
the potential for nitrate leaching from four different types of substrates
(coir, coir : peat, peat, and native soil). There were four replications
of each treatment, with a replication consisting of one crate planted
with 25 bulbs. Two cultivars were used in two separate experiments,
‘Star Fighter’ and ‘Casa Blanca’. Nitrate leaching was determined by
placing an ion-exchange resin bag under each crate at the beginning
of the study. After plant harvest (14–16 weeks), resin bags were collected and analyzed for nitrate content. Plant tissues were dried and
ground and analyzed for nitrogen content. Based on the results of these
studies, it appears that the use of coir, peat, and soil may not influence
plant growth significantly. Substrate type may mitigate the amount of
nitrate leaching through the media. However, the cultivar type may
also influence the degree of nitrate mitigation, since leaching results
varied between the two cultivars.
(128) Determination of Limestone Requirement of Soilless
Root Media for a Specific pH
Pauline H. Andrews, P. Allen Hammer*
Purdue University, Horticulture and Landscape Architecture, West Lafayette, IN, 47907
Limestone requirement tests are routine in agronomic laboratories;
however, no tests exist for soilless root medium although there is still
a need to predict the limestone additions. This research was to develop
a rapid, accurate test to determine the limestone requirement of soilless root media for a specific pH. Thirty-four media formulations were
amended with increasing rates of limestone. Media were incubated
in the greenhouse. Pots were irrigated to container capacity every 2
days with RO-water; pH was recorded after 5 weeks; and limestone
requirement for pH 5.5 was determined for each media. A modified
SMP buffer procedure for mineral soils was used. A 40-mL aliquot of
the SMP buffer was added to 6 g of media, equilibrated for 48 hours
and pH determined. Media-buffer pH was plotted against the incubation
limestone requirement for pH 5.5. A separate regression was required for
media containing coir since the modified SMP buffer test overestimated
the limestone requirement of coir media. The correlation for non-coir
media was –0.97 (Y = -1.19x + 7.52) and -0.94 (Y = –1.12x + 6.14)
for coir media. The procedure was verified using 15 media. Media-buffer pH was determined and the limestone requirement was calculated
using the corresponding regression equation. Two sets of media treatments were potted and incubated in the greenhouse. Rooted cuttings
of geranium ‘Candy Lavender’ were transplanted into one set of pots.
Pots were irrigated every 2 days with RO-water and geraniums were
irrigated with nonacidified fertilizer water. Media pH was determined
at week 5. Media was nonsignificant for pots or geraniums (P ≤ 0.01).
The mean pH of non-coir media was pH 5.66 and 5.67 for pots and
geraniums and pH 5.39 and 5.39, respectively, for coir media.
(129) Effect of Foliar Application of Calcium, Boron, and
Molybdenum in Nutrient Content of Poinsettia Plants
Juan Ayala, Ana-Maria Castillo*, Maria-Teresa Colinas, Joel Pineda
Universidad Autonoma Chapingo, Fitotecnia, Chapingo, Edo. Mexico, 56230, Mexico
The effect of foliar application of calcium, boron, and molybdenum
on macronutrient and micronutrient content of poinsettia (Euphorbia
pulcherrima) plants cv. Supjibi was evaluated. Plants were grown
under greenhouse conditions in 7-inch containers. Fourteen treatments were applied (10 replicates per treatment); these were formed
by three calcium levels (calcium nitrate at 300, 400, and 500 mg·L-1),
boron (borax at 0.2, 0.5, and 0.8 mg·L-1), and molybdenum (sodium
molybdate at 0.3, 0.4, and 0.5 mg·L-1) and their combinations. Plants
were spayed three times during the growing period: 51, 72, and 94
days after transplant. Plants were covered with black polyethylene
from 5 pm to 7 am every day in order to induce bract development.
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N, P, K, Ca, Mg, B, Mo, Mn, Fe, Zn, and Cu content was evaluated 2
weeks after finishing the induction period. The treatment with a combination of Ca+Mo increased by 26% the N content compared with
the control. Application of B+Mo, and Ca+B decreased the P content
by 32% and 28%, respectively. Treatment with Ca+B+Mo increased
foliar K by 46%. B+Mo increased 72.5% Ca content, 38% Mg, and
there was about 75 times more Cu than in the control (2.20 vs. 166.7
mg·L-1). Treatments with Ca and B decreased Mn content by 32.7%.
Ca (500 mg·L-1) decreased B content by 76%. Treatments did not have
any significance on Mo, Fe, and Zn content. As a general conclusion
it can be said that foliar applications of Ca, B, Mo, alone or in certain
combinations, affected significantly the content of foliar nutrients due
to specific nutrient interactions in plants.
(130) Dieffenbachia Calcium Oxalate Crystal Formation
Affected by Cultivars, Nitrogen Rates, and Light Intensity
Hui Cao, Jianjun Chen*, Dennis B. McConnell
University of Florida, Environmental Horticultural Department and Mid-Florida Research
and Education Center, Apopka, FL, 32703
Tissue-cultured explants of Dieffenbachia maculate ‘Exotic Perfection’, D. ‘Snow Flake’, and D. × ‘Tropic Breeze’ were grown on
ebb-and-flow trays subirrigated with nitrogen (N) at 50, 200, or 800
mg·L-1 using a water-soluble fertilizer 17N–2.1P–15.7K for 10 weeks
in a shaded greenhouse under a maximum photosynthetic photon flux
density of 285 μmol·m-2·s-1. Plants were then transferred to interior
rooms under a light level of 8 μmol·m-2·s-1. Samples of the midrib were
taken from the first mature leaf of plants before being placed indoors
and also from the first mature leaf of plants 8 months after growing
indoors. Counts of calcium oxalate crystal idioblasts in cross-sections
of the basal midrib using polarized light microscopy showed that the
number of crystal idioblasts was higher in all three cultivars fertigated
with 200 mg·L-1 N than those fertigated with either 50 or 800 mg·L-1
N. The number of crystal idioblasts in each cultivar grown under 8
μmol·m-2·s-1 was about 50% of the number detected when plants were
grown under 285 μmol·m-2·s-1. ‘Snow Flake’ had the highest number
of crystal idioblasts with counts up to 60 per cross-section, whereas
‘Exotic Perfection’ had the lowest with only 30 per cross-section. This
study shows that in addition to cultivar differences, light intensity and
N can significantly affect calcium crystal formation, and the highest
number of crystal idioblasts occurred when Dieffenbachia cultivars
were grown under optimum conditions.
(131) Nitrogen and Potassium Changes during Growth of
Poinsettia (Euphorbia pulcherrima Wild) ‘Supjibi Red’
Jorge-Moises Rosas-Ramos*1, Ana-Maria Castillo-Gonzalez1,
María Teresa Colinas-Leon1, Joel Pineda-Pineda2
1
Universidad Autonoma Chapingo, Fitotecnia, Chapingo, Edo. Mexico, 56230,
Mexico;2Universidad Autonoma Chapingo, Instituto de Horticultura, Chapingo, Edo.
Mexico, 56230, Mexico
Nitrogen and potassium changes in poinsettia ‘Supjibi Red’ were
evaluated at four stages: vegetative growth, inductive stage, bract
development and flowering. Nitrogen doses were 100, 200, 300, 400,
and 500 mg·L-1 and those of potassium were: 175, 250, 325, and 400
mg·L-1, which were applied constantly with irrigation. Plants were
grown in 7-inch pots with tezontle as the substrate. A completly random experimental design with nine treatments and 10 replicates was
used. Short photoperiod was applied from 61 days after transplant,
covering plants for 14 hours from 7 pm on. Samples for nitrogen and
potassium evaluations were taken from recently grown-up leaves at
25, 50, 75, 100 and 125 days after transplant. Nitrogen absorption
increased up to 75 days after transplant; treatments with 400 and 500
mg·L-1 of nitrogen induced the highest foliar levels 2.44% and 2.6%,
respectively. In the following sampling dates, nitrogen decreased for all
treatments. Potassium content decreased as plants developed; highest
levels were obtained 25 days after transplant. The 325 and 400 mg·L-1
K treatments induced the highest concentrations in leaves 7.04% and
7.02%, respectively. Thus, it is confirmed that nitrogen is required
throughout vegetative growth, and potassium just in the initial stage
of vegetative growth.
HORTSCIENCE, VOL. 40(4), JULY 2005
6/20/05 5:02:49 PM
(132) Withdrawn
(133) Influence of Two Types of Fertilizers on the Growth
and Development of Tissue-cultured Daylilies Transferred
to the Greenhouse
Johnny Carter*, Diondre Palmer, Lianghong Chen
Fort Valley State University, Agricultural Research, Fort Valley, GA, 31030
During Summer 2004, a study was conducted to determine the effect of
two types of fertilizers on the growth and development of tissue-cultured
daylilies transferred to the greenhouse. Peters 20–20–20 water-soluble
fertilizer and a slow-release fertilizer were the two fertilizers evaluated.
Peters 20–20–20 fertilizer was used at 0 (control), 50, 100, and 200
mg·L–1 rates. The slow release fertilizer was used at 2.5 g per 10.2 cm
pot. Each treatment was replicated four times in a randomized completeblock design. After 6 weeks of growth, the results showed that, when
compared to the control, all treatments except for 200 mg·L–1 caused
a significant increase in root growth. Shoot growth was significantly
increased by the 100 mg·L–1 treatment, while the 200 mg·L–1 and slowrelease treatments suppressed shoot growth. Similar to root and shoot
growth, the 100 mg·L–1 treatment caused a significant increase in fresh
weight, while the 200 mg·L–1 and slow-release treatments caused a reduction. These results imply that the 100 mg·L–1 Peters 20–20–20 fertilizer
treatment is the best treatment for maximum growth and development
of tissue-cultured daylilies transferred to the greenhouse.
Poster Session 52—Postharvest Storage
21 July 2005, 1:15–2:00 p.m.
Poster Hall–Ballroom E/F
(47) Optimal Low Pressure Conditions for Long-term
Storage of Fresh Commodities Kill Caribbean Fruit Fly
Eggs and Larvae
Thomas L. Davenport*1, Stanley P. Burg2, Thomas L. White1
1
University of Florida, IFAS, Tropical Research and Education Center, Homestead, FL,
33031; 2VacuFresh Corporation, CEO, Miami, FL, 33133
(48) Prestorage Delay Effects on Soft Scald and Soggy
Breakdown of ‘Honeycrisp’ Apples
Renae E. Moran*
University of Maine, Dept. of Plant, Soil, and Environmental Sciences, Monmouth, ME,
04259
In 2004, prestorage delays and CA storage were compared for occurrence of disorders. Fruit were harvested at a starch index of 5.9. Fruit
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(49) Effect of Low Temperature Storage on Quality and
Enzymatic Activity of Zapote Mamey Fruit (Pouteria
sapota)
Iran Alia-Tejacal1, Maria-Teresa Colinas-Leon*1,
Maria-Teresa Martinez-Damian1, Marcos Soto-Hernández2
1
Universidad Autonoma del Estado de Morelos, Facultad de Ciencias Agropecuarias,
Domicilio conocido, Cuernavaca, Morelos, 62210, Mexico; 2Colegio de Postgraduados,
Instituto de Recursos Naturales, Domicilio Conocido, Montecillo, edo. Mexico, Texcoco,
Edo. de México, 56320, Mexico
Zapote mamey is a climacteric fruit that shows an increase in the content
of carotenoids and total soluble sugars and in the activity of different
enzymes during maturation. In the present study, zapote mamey fruits
were harvested at physiological maturity and stored for 7, 14, and 21
days at 5, 10, and 15 °C, 85% relative humidity (RH). At the same
time, immediately after harvest a group of fruits (control) was kept
and evaluated at ambient temperature (20 °C, 50% to 60% RH). The
objective was to determine the effects of temperature and storage time
on content of carotenoids, and total soluble sugars, as well as to evaluate the enzymatic activity of peroxidase (POD), catalase (CAT), and
superoxide dismutase (SOD). Fruits stored at 5 °C for 14 and 21 days
developed chilling injury, as shown by a negative effect on carotenoids
and total soluble sugars content. The activities of POD, CAT and SOD
were also reduced after storage at 5 °C for 21 days. Fruits stored at
10 and 15 °C for 7, 14, and 21 days showed similar characteristics to
the control fruits in carotenoids and total soluble sugars. Enzymatic
activities were affected only by storage at 10 °C for 21 days. Storage
at 15 °C for 21 days delayed, but did not stop maturation. Results suggest that zapote mamey fruits can be stored at 10 °C with no negative
effect on quality.
(50) Effect of Delayed MA Packaging and Packaging Film
on Quality Maintenance of Fresh-cut Iceberg Lettuce
Ji Gang Kim, Sun Tay Choi*, Chai Il Lim
National Horticultural Research Institute, Postharvest Technology Division, 475 ImokDong, Jangan-Gu, Suwon, Kyeonggi, 440-706, South Korea
Modified atmosphere (MA) packaging has been used to maintain quality
of fresh-cut lettuce, but O2 depletion and excessive CO2 accumulation
can be injurious. This study was conducted to evaluate the effect of
delayed MA packaging using three different films on quality maintenance
of fresh-cut iceberg lettuce. Iceberg lettuce leaves were sliced, washed,
dried, and placed for 0, 5, 10, and 15 hours under air atmosphere at
5 °C. Samples were packaged with 2.9 and 16.6 pmol·kg·Pa·s, oxygen
transmission rate (OTR) films and microperforated film (P-plus), and
stored for 12 days at 5 °C. Results indicated that delayed packaging
affected gas composition (O2 and CO2), fermentative volatile production, off-odor, color, and tissue electrolyte leakage. With 2.9 OTR
film, longer delayed time maintained quality by inhibiting off-odor
development and the accumulation of ethanol. However, delayed
packaging was not effective in maintaining quality of samples packaged with 16.6 OTR film and P-plus film. Regardless of delayed time,
all 16.6 OTR-packaged samples had severe discoloration after 7 days
of storage. All delayed treatments packaged with P-plus film attained
the desired O2 (3–5 kPa) and CO2 levels (10–12 kPa) from day 9 to the
end of storage. A 15-hour delayed packaging into packages prepared
POSTERS–THURSDAY
U.S. regulations prevent importation of fresh horticultural commodities that have not received an approved quarantine treatment assuring
100% mortality of potentially invasive insect pests. Because imported
mangoes are likely to be infested by the Caribbean fruit fly (Anastrepha
suspensa Loew) and other tropical fruit flies such as A. ludens Loew,
A. striata, A. distincta, A. fraterculus, A. serpentina, or A. oblique,
they must be hot-water treated prior to shipment in order to satisfy
quarantine requirement. Hot water treatment often damages the fruit,
especially if it is not fully mature. Hypobaric (low pressure = LP)
intermodal shipping containers developed by the VacuFreshSM Corp.
preserve fresh commodities, such as horticulturally mature mangoes,
far longer than is possible using other technologies. We tested the
ability of over 70,000 Caribbean fruit fly eggs and larvae to survive a
simulated optimal hypobaric condition for shipment of mangoes (15
mm Hg, 98% RH, at the lowest, safe non-chilling temperature, 13 °C).
A. suspensa eggs or larvae were maintained on agar media, flushed
with one air change per hour at the storage pressure, and shielded with
Mylar to prevent radiant heat uptake and limit evaporative cooling.
Nearly 98% of the eggs and larvae were killed within 1 week at 15
mm Hg in eight replicated experiments. All eggs were killed at that
pressure by 11 days, whereas a significant number survived at ambient
pressure. Shipment of fresh produce using this technology promises
to provide quarantine control while preserving the freshness of fully
mature tropical fruits and vegetables.
were exposed to either a 2- or 5-day prestorage delay at 17 °C; or
placed immediately into cold storage (control) at 0.5 °C. An additional
treatment was CA storage at 2.5 °C. In February, occurrence of soft
scald, soggy breakdown, and bitter pit were measured on 40 fruit per
replication. Fruit were from ‘Honeycrisp’/M.26 trees planted in 1994.
Treatments were replicated five times with four trees in each replication. Soft scald was very severe in this year, with 84% of control fruit
being affected. Two-day prestorage delay reduced it to 48% and 5-day
delay to 21%. Soggy breakdown was also severe with 14% of the fruit
being affected. Two- and 5-day delays had no effect on occurrence of
soggy breakdown, but CA storage increased it to 65%. Bitter pit was
very rare and not affected by any of the treatments. These results demonstrate that in severe cases, shorter prestorage delay is not effective
in preventing soft scald or soggy breakdown.
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6/20/05 5:02:50 PM
from 2.9 OTR film and samples packaged with P-plus film maintained
quality by inhibiting off-odor development. The results indicate that
delayed packaging could be an alternative method when fresh-cut lettuce is packaged with low OTR films.
(51) Changes in Phenolic Compounds in Sweetpotatoes
during Low Temperature Storage
M.S. Padda*, D.H. Picha
Louisiana State University, Horticulture, Baton Rouge, LA, 70803
Sweetpotatoes may be potentially high in concentration of certain
phytochemical compounds, including phenolics. Low temperature
stress-induced phenolic compounds may enhance the nutraceutical
value of sweetpotatoes. However, extended exposure to low temperature
results in chilling injury. Cured and non-cured roots of ‘Beauregard’
sweetpotatoes were exposed to low temperature storage (5 °C) for up
to 4 weeks. The total phenolics and individual phenolic acid contents
were determined at weekly intervals using Folin-Denis reagent and
reversed-phase HPLC, respectively. Total phenolics and individual
phenolic acids increased with length of low temperature exposure.
Non-cured roots had a higher phenolic content than cured roots after
4 weeks. A 3-day exposure period to room temperature (22 °C) following removal from low temperature storage typically resulted in
increased phenolics. In a comparison of different tissue locations, the
highest phenolic content was found in peel tissue and the lowest in
the pith tissue. The major individual phenolic acid in all root tissues
was chlorogenic acid.
(52) Postharvest Alleviation of Chilling Injury and
Diseases of Cantaloupe Melons
Christian Krarup*, Oscar Núñez
Universidad Católica de Chile, Ciencias Vegetales, Casilla 306, Santiago 22, Chile
Chilling injury of cantaloupe melons (Cucumis melo, Cantalupensis
group), although variable among cultivars, precludes the use of temperatures close to 0 °C for long term storage or transport. Diseases,
either associated with chilling or independent from it, are usually the
main factor terminating postharvest life of these melons. ‘Colima’,
a Western Shipper cultivar highly sensitive to chilling, was used to
evaluate chilling and disease response to the following treatments:
immersion in water at 60 °C for 1 minute (with or without 150 ppm
chlorine), individual packaging (PVC, whole or perforated), exposure
to air at 38 °C for 12 hours (with or without individual packaging),
and control. After storage for 18 days at 0 °C and a simulated retail
period of 3 days at 20 °C, there were significant differences among
treatments: chilling was alleviated in heat-treated and especially in
plastic-wrapped fruit, and the presence of diseases caused by pathogens
such as Alternaria, Cladosporium, Fusarium, and Rhizopus was markedly reduced by heat treatments. Overall, visual quality was high and
superior in fruit immersed in water at 60 °C with 150 ppm chlorine
due to almost complete supression of diseases. Project financed by
FONDECYT 1020882.
(53) Do Pawpaw Varieties Behave Differently during
Ripening and Cold Storage?
Federica Galli*1, Douglas D. Archbold1, Kirk W. Pomper2
1
University of Kentucky, Department of Horticulture, Lexington, KY, 40546-0091; 2Kentucky State University, 129 Atwood Research Facility, Frankfort, KY, 40601
Pawpaw [Asimina triloba (L.) Dunal] is a highly perishable climacteric
fruit. Generally, fruit may be stored at 4 °C for 4 weeks with minimal
loss in quality or subsequent ripening capacity. However, comparisons
among cultivars and advanced selections for ripening behavior and
postharvest storage life have not been reported. Ideally, cultivars with
superior ripening traits (higher firmness, or a slower rate of firmness
loss) and longer storage life may be identified for the commercial
market. To determine if differences among genotypes may exist,
respiration, C2H4 production, and fruit firmness of six varieties, 8-20,
9-58, ‘Middletown’, ‘PA Golden’, ‘Taytwo’, and ‘Taylor’, were measured during ripening after harvest and after 1, 2, 3, 4, 5, and 6 weeks
of 4 °C storage. No differences were observed among the cultivars
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final6_20July HS.indb 1088
regarding respiration and C2H4 production. Respiratory and ethylene
peaks were detected within 48 hours after harvest or removal from
cold storage. Rapid loss of firmness was measured during ripening at
ambient temperature after harvest and after removal from cold storage
(days 0–3), with some loss during cold storage itself (weeks 1–6). As
expected, firmer fruits at harvest had a lower respiration rate. However,
no obvious differences in ripening behavior or cold storage response
were observed among the six genotypes. As a general guideline, only
firmer fruits should be cold stored, since fruit softening did not stop
at 4 °C. A broader analysis of all of the named cultivars and advanced
selections of pawpaw will be needed to determine if the present results
are generally representative of pawpaw.
Poster Session 53—Vegetable Breeding 2
21 July 2005, 1:15–2:00 p.m.
Poster Hall–Ballroom E/F
(254) Molecular Characterization of Doubled Haploid and
Conventional Onion Lines using AFLPs and SSRs
Ryan Walker*1, Leonard Pike1, Monica Menz2, Kil Sun Yoo1,
Sung Gil Kim1
1
Texas A&M University, Horticulture Science, College Station, TX, 77845; 2Texas A&M
University, Agronomy, College Station, TX, 77843
Onions suffer from severe inbreeding depression, which has prevented
the creation of homozygous inbreds in breeding programs. The creation
of doubled haploid (DH) lines in onion is an anomaly, and provides
a unique opportunity to study both how these lines would perform
in a breeding program and why they do not exhibit more inbreeding
depression. Seven DH lines were developed at Texas A&M University
from five different short-day F1 and F2 populations. Five equivalent
conventional inbred lines, breeding lines developed from the same
parents as the DH lines, have been identified from the onion-breeding program. The DH lines, the conventional inbred lines, and their
parents have been analyzed using SSR and AFLP markers. SSR
markers yielded a polymorphism rate of 55% vs. 3% with the AFLPs.
Analysis has shown remnant heterozygosity both in the parental lines
and in the conventional inbreds and has confirmed the uniformity of
the DH lines. Genetic similarity estimates have been calculated using
the molecular data to determine the suitability of comparing the yield
heterosis of crosses between the conventional lines and the DH lines
in a diallele analysis.
(255) A Comparison of Phenotypic and Marker-assisted
Selection in Cucumber
Matthew D. Robbins*1, Jack E. Staub2, Zhicheng Fan1
1
University of Wisconsin-Madison, Department of Horticulture, Madison, WI, 53706; 2University of Wisconsin-Madison, USDA/ARS, Vegetable Crops Unit, Madison, WI, 53706
To increase yield in cucumber (Cucumus sativus L.), we designed a
recurrent selection program utilizing phenotypic (PHE) and marker-assisted (MAS) selection for the development of multiple lateral branching
(MLB; branches per plant), gynoecious, early genotypes possessing
high fruit length to diameter ratio (L:D). These yield components are
under genetic control of few quantitative trait loci (QTL; 2-6 per trait),
which have been placed on a moderately saturated molecular linkage
map. Four inbred lines, complementary for the target traits, were
intermated and the resulting population underwent MAS and PHE, as
well as random mating (RAN), for three cycles. Selections by PHE
were visually made for all four traits at the whole plant level. Selections based on MAS contained the highest number of desired marker
genotypes from 20 marker loci (SSR, RAPD, SCAR, SNP). Using the
same selection scheme and intensity allowed a direct comparison of
MAS to PHE. Selection was equally effective for MLB and L:D by
MAS (3.5 and 3.0) and PHE (3.6 and 3.0), which were both superior
to RAN (2.8 and 2.8). For earliness (days to anthesis) and gynoecy
(percent female), MAS (41.8 and 26.6) was less effective than PHE
(40.5 and 81.8) and RAN (41.0 and 80.9), which were equal. For
yield (fruit per plant), RAN (1.90) and MAS (1.88) were equal, but
less than PHE (2.15). After three cycles of PHE, further selection by
HORTSCIENCE, VOL. 40(4), JULY 2005
6/20/05 5:02:51 PM
MAS identified superior genotypes, which were intermated. Superior
hybrids were selected by MAS and underwent one backcross generation. In some backcrosses, gains were made in every trait compared to
the PHE Cycle 3 mean, while in other backcrosses, gains were made
only in some traits. Improvement by MAS was very effective during
line extraction for these yield components.
(256) Evaluation of 25 Varieties of Race 3 Bacterial Spot
Resistant Bell Peppers
Russell T. Nagata*1, Kenneth L. Pernezny1, Darrin M. Parmenter2,
Eugene McAvoy3, Kent E. Cushman4
1
University of Florida, Everglades Research and Education Center, Belle Glade,
FL33430;2University of Florida, Palm Beach County Extension, West Palm Beach,
FL33415; 3University of Florida, Henery County Extension, Labelle, FL 33975;
4
University of Florida, Southwest Florida Research and Education Center, Immokalee,
FL 34142
Twenty-five varieties of bell peppers (Capsicum annuum) were
transplanted in commercial pepper fields in Immokalee and Delray
Beach, Fla., to evaluate horticultural characteristics and resistance to
race 3 bacterial spot of peppers caused by Xanthomonas campestris
pv. vesicatoria. All cultural and management procedures were based
on commercial best management practices. Eighty to 90% of marketable fruits had three or four lobes. Total marketable fruit yield from
three harvests ranged from 4596 to 7089 kg·ha-1 and marketable
fruit number ranged from 20,571 to 31,224 fruit/ha. Most fruit were
slightly elongated with length to diameter ratios between 1.1 and 1.2.
Seminis 7602 had a ratio of one, while lines ACR 252, PRO2R-3, and
PR99R-16 had ratios of 1.40, 1.36, and 1.28, respectively. Significant
differences were observed for fruit wall thickness, with those grown in
Delray Beach having thicker fruit walls that averaged 7.5 mm vs. 5.3
mm for the Immokalee site. Bacterial spot infection at both sites did
not affect yield, due to late natural infection of the field. Susceptible
control ‘Jupiter’ had a mean foliage disease incident rating of 26%
after the final harvest and was surpassed only by 7682 and 8328 from
Enza. The most resistant lines with disease ratings of <3% were 5776,
7141, and 8302 from Seminis, and Telstar from Hazera.
(257) Pepino Mosaic Virus: Variability in U.S. Isolates
Clarissa J. Maroon-Lango1, Mary Ann Guaragna1, Ramon Jordan1,
John Hammond1, Murali Bandla2, Steve Marquardt2, John R. Stommel*3
1
USDA, ARS, Floral and Nursery Plant Research Unit, Beltsville, MD, 20705; 2Agdia,
Inc., Elkhart, IN; 3USDA, ARS, Vegetable Laboratory, Beltsville, MD, 20705
HORTSCIENCE, VOL. 40(4), JULY 2005
final6_20July HS.indb 1089
Mary Ruth McDonald*1, Kevin Vander Kooi2, Philipp Simon3
1
University of Guelph, Plant Agriculture, Crop Science Bldg., Guelph, Ontario, N1G
2W1, Canada; 2University of Guelph, Plant Agriculture, Kettleby, Ontario; 3USDA, ARS,
Vegetable Research Unit, Department of Horticulture, Madison, WI, 53706
Cavity spot of carrot, caused by several species of Pythium, is endemic
in many carrot production areas of the world, including the Holland/
Bradford Marsh region of Ontario, Canada. Field trials were conducted
from 2002–04 to determine if carrots with different pigments varied in
susceptibility to the disease. Carrots from the USDA breeding program
at the University of Wisconsin were seeded in muck soil (pH 6.4, 60%
organic matter) on 28, 30, and 27 May, harvested 22, 22, and 23 Oct.,
and assessed for disease on 5, 8, and 10 Dec. 2002, 2003, and 2004,
respectively. The carrots were white (W 105-7), yellow (W 102-1),
dark orange (W 101-23), red (W 104-3), and purple (W 106-3). Cultivar
‘Cellobunch’ was included in 2003 and 2004. Twenty-five carrots
of each of four replicate plots were assessed in 2002 and 2003, and
50 carrots were assessed in 2004, for disease incidence and severity
[disease severity index (DSI), based on the size of the largest lesion
per carrot]. Disease incidence was moderate in 2002 and 2003 (34%,
33%), and high in 2004 (60%). Consistent differences in susceptibility
to cavity spot were identified over the three years of trials. The purple
carrot had the lowest incidence (12%) and severity (7 DSI) of cavity
spot, followed by the dark orange carrot (39%, 22 DSI) as compared to
the susceptible yellow carrot (58%, 41 DSI). There was no difference
in disease reaction between the yellow and white carrots. ‘Cellobunch’
had the same reaction as the dark orange carrot. Studies are needed
to determine whether the pigments themselves cause differences in
the disease response.
(259) A Genetic Linkage Map and a cDNA Library for
Watermelon
Amnon Levi1, C.E. Thomas1, Angela Davis2, O.U.K. Reddy3,
Y. Xu4, X. Zhang5, A. Hernandez6, G. Gusmini7, Todd C. Wehner*7,
J. King8, S.R. King9
1
USDA, ARS, U.S. Vegetable Laboratory, Charleston, SC, 29414; 2USDA, ARS, South
Central Agricultural Research Laboratory, Lane, OK, 74555; 3West Virginia State University, Department of Biology, Institute, WV, 25112; 4China National Engineering Research
(NERCV), Center for Vegetables, Beijing, 100089, China; 5Syngenta Seeds, Inc., 21435
Road 98, Woodland, CA 95695; 6University of Illinois at Urbana-Champaign, Biotechnology Center-W.M. Keck Center for Comparative and Functional Genomics, Urbana, IL
61801; 7North Carolina State University, Department of Horticultural Science, Raleigh,
NC 27695; 8Seminis Vegetable Seeds, Inc., Woodland, CA 95695; 9Texas A&M University,
Department of Horticultural Sciences, College Station, TX 77843
A genetic linkage map was constructed for watermelon based on a
testcross population and an F2 population. The testcross map includes
312 markers (RAPD, ISSR, AFLP, SSR, and ASRP). This map covered
a genetic distance of 1385 cM, and identified 11 large (50.7-155.2
cm), five intermediate (37.5-46.2 cm), and 16 small linkage groups
(4.2-31.4 cm). Most AFLP markers are clustered in two linkage
regions, while all other markers are randomly dispersed throughout
the genome. Many of the markers in this study were skewed from the
classical (Mendelian) segregation ratio of 1:1 in the testcross or 3:1
in the F2 population. The order of the markers within linkage groups
was similar in the testcross and F2 populations. Additionally, a cDNA
library was constructed using RNA isolated from watermelon flesh
1 week (rapid cell division stage), 2 weeks (cell growth and storage
deposition stage), 4 weeks (maturation stage), and 5 weeks (mature
fruit) after pollination. More than 1020 cDNA clones were sequenced,
and analyzed using the basic local alignment search Tool (BLAST).
The sequenced cDNA clones were designated as expressed sequenced
tag (EST). The ESTs were searched for simple sequence repeats. About
7% of the ESTs contained SSR motifs. The ESTs containing SSRs
are being used to design PCR primers and the putative markers are
being tested for polymorphism among the parental lines of the mapping populations. Polymorphic markers will then be mapped using
the mapping populations.
POSTERS–THURSDAY
Pepino mosaic virus (PepMV) was first found in pepino (Solanum
muricatum) growing in coastal Peru in 1974 and described in 1980;
it reappeared in protected tomato (Lycopersicon esculentum) in the
Netherlands in 1999. Since then, it has been reported to occur in
tomato in several countries including Austria, Belgium, Canada,
France, Germany, Italy, Peru, Spain and the Canary Islands, the United
Kingdom, and in 11 states within the United States. Three strains of
PepMV found in the United States have been cloned and sequenced.
Full-length genomic sequences were obtained for two strains, PepMVUS1 and PepMV-US2, from co-infected tomato plant samples from
Arizona. The 3’-end sequence of PepMV-US3 came from infected
tomato fruits from Maryland. The genome organization, motifs and
domains typical of the genus Potexvirus, and of other PepMV isolates,
were found in full-length sequences of both US1 and US2 isolates.
Direct comparison of US1 and US2 at the nucleotide level revealed an
86.3% identity; whereas, when individually compared to the French
and Spanish isolates, which share ~99% identity at the nucleotide level,
US1 and US2 had 82% and 79% identities to each, respectively. Pairwise gene-for-gene comparisons between United States and European
isolates revealed a similar trend. While unique, US1 is more closely
related to the previously reported European isolates than is US2. The
CP of US3 is nearly identical to the European isolates at the amino
acid level. None of 18 tomato germplasm accessions or 10 cultivars
were resistant to mechanical inoculation with US3; in contrast, no
infection was detected in nine pepper cultivars or four germplasm
accessions. Plants grown from seeds of infected tomato fruits did not
test positive for PepMV.
(258) Differential Response of Colored Carrots to Cavity
Spot
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6/20/05 5:02:52 PM
(260) Development of SCAR and CAPS Markers Linked
to Tomato Begomovirus Resistance Genes Introgressed
from Lycopersicon chilense
Yuanfu Ji, John W. Scott*
University of Florida, Gulf Coast Research & Education Center, Wimauma, FL, 33598
Resistance to begomoviruses tomato mottle virus (ToMoV) and tomato
yellow leaf curl virus (TYLCV) has been introgressed to tomato (Lycopersicon esculentum) from L. chilense accessions LA 1932, LA 2779,
and LA 1938. Resistance genes have been mapped to three regions on
chromosome 6 using randomly amplified polymorphic DNA (RAPD)
markers. We call these regions 1, 2, and 3. To facilitate breeding by
marker assisted selection, advanced breeding lines with resistance from
the above sources were assayed for the presence of RAPD markers to
determine which were most tightly linked to begomovirus resistance.
The best RAPD markers were then converted to sequence characterized
amplified region (SCAR) markers or cleaved amplified polymorphic
sequence (CAPS) markers. In addition, selected restriction fragment
length polymorphism (RFLP) markers near the three regions were
converted into CAPS markers, which were tested for association
with the advanced breeding lines. Only LA 2779 derivatives have
the L. chilense introgression in region 1, which is near the location of
the Ty-1 gene and spans across CAPS markers 32.5Cla and TG118.
Two region 1 RAPD markers UBC197 and UBC621 were converted
co-dominant SCAR or CAPS markers, which were present in all 16
resistant breeding lines tested. Derivatives from all three accessions
have introgressions in region 2. Further assays with more markers in
this region are under way to determine the lengths and locations of
the introgressions. No tightly linked RAPD markers have been found
for the resistance gene from LA 1932 in region 3. RFLP and CAPS
markers are being used to more precisely locate the region 3 gene.
(261) A PCR-based Linkage Map of Broccoli [Brassica
oleracea (L.) var. italica] and Comparisons with Existing
Brassica Maps
Allan Brown1, Khalid Ibrahim*1, Sultana Islam2, Elizabeth Jeffery3,
John Juvik4
1
University of Illinois, Department of Natural Resources and Environmental Sciences,
Urbana, IL, 61801; 2Department of Crop Science; 3Department of Food Science and Human
Nutrition; 4Department of Natural Resources and Environmental Sciences
A set of 216 PCR-based molecular markers was screened for polymorphisms using two morphologically dissimilar broccoli lines, ‘VI-158’
and ‘BNC’. Fifty-nine of these markers, representing 69 detected
polymorphisms and two morphological markers, were used to construct
a genetic linkage map of broccoli [Brassica oleracea (L.) var. italica]
from a population of 162 F2:3 families generated from the cross between
these two lines. Ten genetic linkage groups were generated that spanned
a distance of 468 cM with an average interval width of 9.4 cm. This
map represents the first combined SSR and SRAP map of Brassica
oleracea. Comparisons are made to existing maps of Brassica napus
and to inter-specific maps of Brassica oleracea. To our knowledge
this is the first linkage map of broccoli [Brassica oleracea (L.) var.
italica] and should provide a useful tool for the genetic analysis of
traits specific to the italica subspecies.
Poster Session 54—Produce Quality, Safety, and Health
21 July 2005, 1:15–2:00 p.m.
Poster Hall–Ballroom E/F
(464) Antioxidant Activity in Lingonberries
(Vaccinium vitis-idaea L.)
Shiow Wang*1, Ross Penhallegon2
1
2
U.S. Department of Agriculture, Fruit Laboratory, BARC-W, Beltsville, MD, 20705;
Oregon State University, Lane County Extension
Lingonberries have been shown to contain high antioxidant activity.
Fruit from different cultivars of lingonberry (Vaccinium vitis-idaea L)
were evaluated for fruit quality, antioxidant activity, anthocyanin and
phenolic contents. The fruit soluble solids content (SSC), titratable
acids (TA), antioxidant capacity, anthocyanin and phenolic contents
1090
final6_20July HS.indb 1090
varied with cultivars. The SSC ranged from 12.9% to 16.9%, the TA
ranged from 0.31% to 0.41% and the ratios of SSC/TA ranged from
35.37 to 51.21. Lingonberries contain potent free radical scavenging
activities for DPPH., ROO. , .OH and O2.- radicals. The oxygen radical absorbance capacity (ORAC) values from acetone extraction of
lingonberries ranged from 58.5–223.6 μmol of Trolox equivalents
(TE)/g fresh berries. The ED50 values for DPPH-radical scavenging
ranged from 5.91–11.77 mg fresh weight. The DPPH-radical scavenging activity correlated with ORAC values with a R2 of 0.8009. ESR
spectrum showed that 50 mg·mL-1 of lingonberry extract decreased .OH
radicals by 83% and O2.- radicals by 99%. Cyanidin 3-galactoside was
the most dominant anthocyanin and contributed the most antioxidant
activity in lingonberries. The antioxidant properties of lingonberries
may play an important role in protecting cells against the oxidative
damage caused by free radicals.
(465) Inhibitory Effect of Lingonberry (Vaccinium
vitis-idaea L.) Extracts on Activator Protein-1, Nuclear
Factor-KappaB, and Mitogen-activated Protein Kinases
Shiow Wang*1, Ren-tian Feng2, Linda Bowman2, Ross Penhallegon3, Min Ding2
1
2
3
U.S. Department of Agriculture, Fruit Laboratory, BARC-W,Beltsville, MD, 20705;
Center for Disease Control and Prevention, Pathology and Physiology Research Branch;
Oregon State University, Lane County Extension
The effects of lingonberry (Vaccinium vitis-idaea L.) extracts on
activator protein-1 (AP-1), nuclear factor-kappaB (NF-κB), and mitogen-activated protein kinases (MAPKs) were evaluated. Pretreatment
of JB6 P+ mouse epidermal cells with lingonberry extracts produced
a dose-dependent inhibition of AP-1 and NF-κB induced by either
12-O-tetradecanoylphorbol-13-acetate (TPA) or ultraviolet-B (UVB)
light. Lingonberry extracts blocked UVB-induced phosphorylation
of MAPK family members ERK1, ERK2, and p38, but not JNK.
Lingonberry extracts also prevented TPA-induced phosphorylation of
ERK1 and ERK2. Results of soft agar assays indicated that lingonberry
extracts suppressed TPA-induced neoplastic transformation of JB6 P+
cells in a dose-dependent manner. Lingonberry extracts also induced
the apoptosis of human leukemia HL-60 cells in a dose-independent
manner. These results suggest that ERK1 and ERK2 may be inhibited
by lingonberries, which results in suppression of AP-1 and neoplastic
transformation in JB6 P+ cells and causes cancer cell death by an
apoptotic mechanism in human leukemia HL-60 cells.
(466) Comparison of Autumnberry and Cornelian
Cherry Antioxidant Potential with that of Well-known
Fruit Crops
Mustafa Ozgen*1, Artemio Z. Tulio, Jr.2, Aparna Gazula2,
Joseph C. Scheerens2, R. Neil Reese3, A. Raymond Miller2,
Shawn R. Wright4, Brent L. Black5, Ingrid M. Fordham5
1
GOP Univ, Horticulture, Tasliciftlik, Tokat, 60240, Turkey; 2The Ohio State Univ.,
OARDC, Horticulture and Crop Science, Wooster, OH, 44691; 3South Dakota State
Univ., Biology/Microbiology, Brookings, SD, 57007; 4The Ohio State Univ., OARDC
South Centers, Piketon, OH, 45661; 5USDA–ARS Henry A. Wallace Beltsville Agr. Res.
Cnter., Fruit Laboratory, Beltsville, MD, 20705
Autumnberry (Elaeagnus umbellata, “A”) and cornelian cherry
(Cornus mas, “CC”) genotypes were examined for mineral composition,
anthocyanin, phenolic and tannin contents, antioxidant characteristics
and levels of individual phenolic compounds via GC-MS. Values
were compared with those of 58 cultivars of blackberries (“B”), black
raspberries (“BR”), cranberries (“C”), elderberries (“E”), grapes
(“G”), red raspberries (“RR”) and strawberries (“S”). The phenolic
content of “CC” (6955 μg·gfw-1) was greater than 2× that of “B”, “BR”
and “E”. Phenolic contents of “A” samples (1058-1776 μg·gfw-1)
were similar to those of “RR”, red “G” and “S”. Anthocyanin levels
in “CC” (270 μg·gfw-1) resembled those in “C”. “A” did not contain
anthocyanins. Fruit of “CC” and “A” possessed high tannin levels
(9291 μg·gfw-1 and 1410–5403 μg·gfw-1, respectively) and exhibited
high antioxidant potential (μmol·gfw-1 trolox equiv.). DPPH and FRAP
values of “CC” (72.1 and 94.9, respectively) were greater than 2×
those of “BR”. DPPH values of “A” (23.9–56.2) were ≥ values for
“BR”, whereas “A” FRAP values (13.3–34.0) were similar to those
HORTSCIENCE, VOL. 40(4), JULY 2005
6/20/05 5:02:54 PM
of “B” and “RR”. However, the lipid-soluble antioxidant potential of
lycopene-rich “A” was substantial. Levels of individual compounds
varied among cultivars. Ca and Mg contents of “A” were less than
those found in “CC” and “BR”. Other mineral levels were comparable.
(467) Anthocyanins as Primary Antioxidants in Black
Raspberries
Artemio Z. Tulio, Jr.*1, Mustafa Ozgen2, R. Neil Reese3,
Steven J. Schwartz4, Qingguo Tian4, Gary D. Stoner5,
A. Raymond Miller1, Joseph C. Scheerens1
1
The Ohio State Univ., OARDC, Horticulture and Crop Science,Wooster, OH, 44691;
GOP Univ., Horticulture, Tasliciftlik, Tokat, 60240, Turkey; 3South Dakota State Univ.,
Biology and Microbiology, Brookings, SD, 57007; 4Ohio State Univ., Food Science and
Technology, Columbus, OH, 43210; 5Ohio State Univ., Div. Hematology and Oncology,
Col. Medicine, James Cancer Hosp. and Res. Inst., Columbus, OH, 43210
2
excess of (30–50×) the AO capacity being measured, more than one
assay is used to describe the total AO activity of fruit samples. Thus,
there may not be a single AO assay method that completely defines
the AO activity of a given fruit.
(469) Replacing Cantaloupe with Orange-fleshed
Honeydew Melon: Antioxidant Metabolism
D. Mark Hodges*1, Gene E. Lester2, Robert D. Meyer2,
Vivian E. Willmets1, Michele L. Elliot1
1
Agriculture and Agri-Food Canada, Atlantic Food and Horticulture Research Centre,
Kentville, Nova Scotia, B4N 1J5, Canada; 2USDA-ARS, Kika de la Garza Subtropical
Agricultural Research Center, Weslaco, TX, 78596
(468) Comparison of Methods to Determine Antioxidant
Levels in Fruit
(470) Lycopene Content of Mini Watermelon Varieties
Grown at Four Locations
Mustafa Ozgen*1, Artemio Z. Tulio, Jr.2, A. Raymond Miller2,
R. Neil Reese3, Joseph C. Scheerens2
Penelope Perkins-Veazie*1, Julie Collins1, Richard Hassell2,
Steve Olson3, Donald Maynard4, Jonathan Schultheis5,
Missy O’Hern6, Toni Magby6, Shelli Magby6
1
GOP Univ., Horticulture, Tasliciftlik, Tokat, 60240, Turkey; 2The Ohio State Univ.,
OARDC, Horticulture and Crop Science, Wooster, OH, 44691; 3South Dakota State Univ.,
Biology and Microbiology, Brookings, SD, 57007
In preliminary studies, we found that relative and absolute antioxidant
(AO) levels varied within and among small fruit types. AO levels
were affected by assay method used, time of reaction, volume of
sample, and the ratio of reactants to total AO activity. To identify
the physicochemical parameters that affect accuracy and reproducibility, a series of experiments were conducted to test the roles of AO
assay, different AOs, and AO concentration on measured AO content
and reaction kinetics. Three assays (DPPH, FRAP, ABTS) were used
to evaluate AO capacity of seven fruit types (black and red raspberry, blackberry, strawberry, grape, elderberry, and cranberry) and
nine purified AOs (ascorbic, caffeic, chlorogenic, gallic, and ellagic
acids, α-tocopherol, trolox, cyanidin-3-glucoside, and quercetin).
Ascorbic acid, trolox, caffeic acid, chlorogenic acid, and α-tocopherol
exhibited simple reaction kinetics and reached endpoints quickly,
regardless of assay. Gallic and ellagic acids, quercetin, cyanidin-3glucoside, and all fruit extracts exhibited more complex kinetics and
long reaction times (>70 min) to reach an endpoint. Moreover, the
latter four AOs had the highest AO capacity among the compounds
tested. We observed differences in reactivity between assays, compounds and fruit extracts, but relative AO activity was comparable,
although the absolute values differed. Since AO capacity of fruit
extracts is a composite of the individual AOs present, it is important
that reactions progress to near steady state, assay reactants are in
HORTSCIENCE, VOL. 40(4), JULY 2005
final6_20July HS.indb 1091
1
USDA-ARS, SCARL, Hwy. 3 West, Lane, OK, 74555; 2Clemson University, Horticulture, Charleston, SC, 29414; 3University of Florida, Research Center, Quincy, FL, 32351;
4
University of Florida, Horticulture; 5North Carolina State University, Horticulture;
6
Southeastern Oklahoma State University, Biological Sciences
Mini watermelons are the size of cantaloupes and weigh 1.5 to 3 kg
(4 to 8 lbs). Melons of 18 selections were grown in replicated trials in
North Carolina, South Carolina, and north and south Florida. Melons
were harvested when ripe, and samples of heart and locule tissue were
frozen and sent to Lane, Okla. A total of 960 samples, representing 612 melons per selection per location, were analyzed for total lycopene
content using colorimeter and spectrophotometer methods. Subsamples
of ‘Mohican’, ‘Hazera 6007’, ‘Vanessa’, ‘Petite Treat’, and ‘Precious
Petite’ were analyzed by HPLC for carotenoid profiles. Total lycopene
content ranged from 52 to 108 μg·g-1, depending on variety. Selections
were grouped into two levels of lycopene content. The varieties Precious Petite, Petite Perfection, Betsy, Bonny, Petite Treat, Valdoria,
Vanessa, Hazera 5133 and 5138, RWT 8149, 8155, 8162 had 60 to
79 μg·g-1 lycopene and the varieties Hazera 6007, 5123, 5109, 5177,
Mohican, and Extazy had 80 to 100 μg·g-1. Melons harvested from the
Florida locations had more total lycopene than those from North and
South Carolina. ‘Precious Petite’ had more β-carotene as a percentage
of total carotenoids than other varieties tested. These results indicate
that lycopene content is affected primarily by germplasm and also
by environment.
POSTERS–THURSDAY
Anthocyanins in black raspberry extracts may play a key role in the
regulation of oncogene expression in cancer cell cultures. Variations in anthocyanin levels of ‘Jewel’, ‘Mac Black’, and ‘Bristol’
black raspberries grown at seven commercial farms in Ohio were
investigated using HPLC and uv-vis spectrometry. Cyanidin-3-rutinoside (cy-3-rut) and cyanidin-3-(2G-xylorutinoside) (cy-3-2-xyl),
the two major compounds present in all cultivars (≈2:1), were highly
correlated with total anthocyanin contents. Sample variation in total
anthocyanin, cy-3-rut, and cy-3-2-xyl levels was greater among
commercial farms than among cultivars grown at the same location.
The antioxidant activities of cy-3-rut, cyanidin-3-glucoside, cyanidin3,5-diglucoside (cy-3,5-diglc), and pelargonidin-3-glucoside from
purified extracts were determined using the free radical scavenging
assays DPPH and ABTS, and the ferric reducing power assay FRAP.
All pure anthocyanins showed strong antioxidant potentials except
for cy-3,5-diglc. Cy-3-rut was identified and quantified as the dominant anthocyanin in black raspberries and was also the most potent
antioxidant. Results suggest that anthocyanins, cy-3-rut in particular,
may function as the primary antioxidants in black raspberries. Genetic
and environmental variation in the anthocyanin contents necessitate
characterization of the antioxidant and anthocyanin levels in fruits
from any given source prior to measuring biological and medicinal
activities.
Consumption of phytochemicals has been associated with reduced
risks of human health dysfunctions such as cancers and heart disease.
Such information has led to increased sales of fruits and vegetables.
For example, in the United States, an estimated 23% increase in
melon consumption (up to 13.2 lbs/capita/annum) has been recorded
over 16 years. However, some health issues have been attributed to
cantaloupe due to bacteria such as Salmonella attaching to inaccessible
sites, such as the rind netting. Honeydew melons do not have a netted rind. The purpose of this study was to compare concentrations of
antioxidants between cantaloupe and both green- and orange-fleshed
honeydew melons during 14 days of storage to determine if orangefleshed honeydew melon would represent a feasible alterative to
cantaloupe to the increasingly health/food safety-conscious consumer.
Cantaloupe (‘Cruiser’; C), green-fleshed Honeydew (‘HoneyBrew’;
HB), and orange-fleshed Honeydew (‘OrangeDew’; OD) melons
were harvested in Texas at the beginning and at the end of the production season. β-carotene content was highest in OD, followed by
C; no β-carotene was detected in HB. β-carotene levels did not change
during storage. Phenolic levels increased in all three melon species
during storage, whereas total ascorbate content declined in OD and
in early harvest HB. Ascorbate peroxidase activities were lowest in
OD, perhaps due to the lower ascorbate levels; little difference between the melon species in activities of the other ascorbate-associated
enzymes were observed. Based on the phytochemicals measured in
this study, choosing non-netted OD over netted C in order to reduce
potential exposure to pathogens would not represent a less healthy
food choice.
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6/20/05 5:02:55 PM
(471) Application of Mustard and Hop Extract Agents
Mixed with Sucrose Fatty Acid Esters as a Food
Preservative for Fresh-cut Vegetables
(473) Influences of Fertilizer Source and Insecticide
Application on Phenolic Compounds in Pac Choi
(Brassica rapa L.)
Daisuke Hamanaka*, Takashi Watakabe, Kazuyuki Kitano,
Hidemi Izumi
Xin Zhao*1, Edward Carey2, James Nechols3, Kim Williams1,
Weiqun Wang4
Kinki University, School of Biology–Oriented Science and Technology, Uchita, Wakayama,
6496493, Japan
1
Cabbage shreds and cucumber slices were dipped in water or solutions
of mustard extract agent (WASAOURO®, Mitsubishi-Kagaku Foods
Corp.) and hop extract agent (HOPREX®, Mitsubishi-Kagaku Foods
Corp.) with or without sucrose fatty acid esters (SE; Mitsubishi-Kagaku
Foods Corp.) and stored in MA packaging at 10 °C. With cabbage
shreds, treatment with mustard extract agent reduced the depletion
of O2 and accumulation of CO2 and ethylene in MA packaging and
the reduction was greater when mixed with SE. Treatment with the
combination of mustard and hop extract agents with SE also had suppressing effects on respiration and ethylene production of cabbage
shreds throughout the MA storage period. Counts of mesophilic aerobic
bacteria and coliforms were 0.3 to 0.7 logs lower in cabbage shreds
treated with mustard extract agent with or without SE than with the
water-dipped control for the first 2 days of storage at 10 °C. However,
mustard extract agent stimulated the growth of lactic acid bacteria.
When hop extract agent was combined with mustard extract agent with
SE, counts of mesophilic aerobic bacteria, coliforms, and lactic acid
bacteria on treated cabbage shreds were reduced by 0.8, 1.6, and 2.6
logs, respectively, relative to control samples after 5 days of storage.
Cucumber slices treated with mustard extract agent with or without
SE accelerated respiration and ethylene production and did not retard
any bacterial growth during MA storage at 10 °C.
(472) Yeast Expressed Tomato β-Galactosidases 1, 4, and
5 Have Activity against Synthetic and Plant-derived Cell
Wall Substrates
Megumi Ishimaru*1, David L. Smith2, Kenneth C. Gross2
1
Osaka Prefecture University, Graduate School of Life and Environmental Sciences,
Gakuen-cho, 1-1, Sakai, Osaka, 599-8531, Japan; 2USDA-ARS, Produce Quality and
Safety Lab., Beltsville, MD, 20705
Fruit softening occurs by several mechanisms, including modifications of cell wall structure by wall degrading enzymes. The most
prominent change in tomato fruit pericarp wall composition is the
loss of galactosyl residues throughout development and especially
during ripening. In order to understand the role of galactosyl turnover
in fruit softening, we successfully produced three recombinant tomato
β-galactosidase/exo-galactanase (TBG) fusion proteins in yeast. TBG1,
4 and 5 enzyme properties and substrate specificities were assessed.
Optimum pH of TBG1, 4 and 5 was 5.0, 4.0, and 4.5 and optimum
temperature was 40~50, 40, and 40 °C, respectively. The Kms for
TBG1, 4 and 5 were 7.99, 0.09, and 2.42 mM, respectively, using pnitrophenyl-β-D-galactopyranoside as substrate. Using synthetic and
plant-derived substrates, TBG1 and 5 released galactosyl residues from
1→4 linkages. TBG4 released galactosyl residues from a wide range
of plant-derived oligosaccharides and polysaccharides. Using tomato
fruit cell wall material, TBG1, TBG4 and TBG5 released galactosyl
residues from a variety of fruit stages and cell wall fractions. TBG4
released the most galactosyl residues from the ASP fraction and especially the ASP fraction from fruit at the turning stage. Interestingly,
even though walls from Turning fruit stage contain less total galactosyl
residues than at the Mature Green stage, TBG4 released 3–4 fold more
galactose from the CSP and ASP fractions from Turning fruit. These
results suggest that changes in structure of wall pectic polysaccharides
leading up to the Turning stage may cause the wall to become more
susceptible to hydrolysis by the TBG4 product.
1092
final6_20July HS.indb 1092
Kansas State University, Horticulture, Forestry and Recreation Resources, Manhattan, KS,
66506-5506;2Kansas State University, Horticulture, Forestry and Recreation Resources,
Olathe, KS, 66061 3Kansas State University, Entomology, Manhattan, KS, 66506-4027;
4
Kansas State University, Human Nutrition, Manhatttan, KS, 66506-1407
Implications of dietary phenolic compounds for human health and disease
prevention have been indicated by a body of literature. A greenhouse
pot study was performed to investigate the impacts of fertilizer source
and preventive insecticide application on phenolic compound levels
in pac choi [Brassica rapa (L.) cv. Mei Qing]. A two-way randomized
complete-block design with five replications was used in this experiment. Fertilizer source consisted of two levels: conventional fertilizer
(pre-plant application of Osmocote slow-release fertilizer), and organic
fertilizer (pre-plant application of vermicompost and fertigation with
compost tea and fish emulsion). Insecticide application consisted of
three levels: organic (pyrethrin) vs. conventional (permethrin), and a
plain water control. At harvest, total phenolics and individual phenolic
compounds in pac choi leaves (blades) were analyzed by Folin assay
and HPLC, respectively. Head weight of pac choi was significantly
higher under conventional fertilizer treatment, while it was not affected
by insecticides. Total phenolic content of pac choi was significantly
increased by organic fertilizer treatment. HPLC results indicated that
organic fertilizer treatment resulted in significantly higher levels of
individual phenolic compounds, including chlorogenic acid and ferulic acid. In contrast, preventive insecticide application showed little
effect on the phenolics in pac choi. Correlation analysis excluded the
influence of plant size (head weight) on phenolic content in pac choi.
Differential N-forms, rates of nutrient release, and/or variable nutrient
content in organic and conventional fertilizer treatments may contribute
to elevated phenolic content in organically fertilized pac choi.
(474) A Selected Yeast for Control of Aspergillus flavus in
Pistachio Orchards
Dan E. Parfitt*1, Siov B. Ly2, Ali A. Almehdi1, Helen Chan,1
Sui-Sheng T. Hua2
1
University of California, Davis, Dept. of Plant Sciences, Davis, CA, 95616; 2USDA-ARS,
Western Regional Research Center, Albany, CA, 94710
Aspergillus flavus produces aflatoxin, a cancer-causing contaminant of
pistachio in many production areas. A superior yeast strain of Pichia
anomala has been demonstrated to inhibit the growth of A. flavus in the
laboratory. It was selected for further study and potential release based
on tests of durability and ability to inhibit A. flavus growth. This strain
has been tested in the field for the past two years to evaluate its ability
to survive in a field environment and to inhibit A. flavus production. The
yeast was evaluated in the field to determine if: 1) the biocontrol yeast
can survive in pistachio orchards; 2) the yeast has no phytotoxic effects
on the pistachio trees or nuts; and 3) the yeast can be demonstrated
to control A. flavus in the field. Studies during 2003 were conducted
using a replicated experiment with three yeast concentrations and a
water control. Treatments applied later in the season were found to be
most effective. Highest yeast concentrations were observed just prior
to harvest. Three spray concentrations and a water control were applied to evaluate possible phytotoxic effects on pistachio during 2004.
No differences in leaf or nut appearance, in nut percent splits, or dry
weight were observed for any of the treatments when compared to the
water control. Artificial wounding experiments were also conducted
during 2003 and 2004 to simulate the occurrence of early split nuts, the
primary repository for A. flavus contamination. A 5× reduction in A.
flavus colonization was observed on treated wounded nuts vs. untreated
wounded nuts. A 5× reduction in A. flavus sporulation was also observed
on treated wounded nuts vs. untreated wounded nuts.
HORTSCIENCE, VOL. 40(4), JULY 2005
6/20/05 5:02:57 PM