bluuebunny/crossref_metadata_2025 huggingface dataset:
THE EFFECT OF THE SOURCE OF PH-ADJUSTMENT ACIDS ON UPTAKE AND TRANSPORT OF THE IONS FOR CUCUMBER PLANTS GROWN IN NFT.
Authors: El-Behairy U. A. , Burrage S.W. , Abou-Hadid A.F. , El-Beltagy A.S.
Published: April 2024

An experiment was conducted to investigate the effect of using nitric acid, phosphoric acid and nitric: phosphoric 3:1 to adjust the pH in NFT solution on uptake and transport of phosphorus, zinc and manganese ions on cucumber (Cucumis sativus) plants cv. Farbiola. Phosphorus concentration was increased to about 450 ppm when phosphoric acid used to adjust the pH. Increasing phosphorus concentration in NFT solution did not increase % of phosphorus in the leaves, but increased it in the roots. As a result of increasing % of phosphorus in the root. Manganese and zinc transport were increased from the root to the leaves.
EASTERN BLACK (SOLANUM PTYCANTHUM) INTERFERENCE WITH PEA.
Authors: Crotser Michael P. , Masiunas John B.
Published: April 2024

Field and greenhouse experiments determined the critical period for eastern black nightshade control in processing peas and the effect of nitrogen on nightshade competitiveness. `Spring' peas were drilled with a 18 cm between row spacing on May 29 and July 31. Nightshade at 10 plants m-2 were transplanted at 0, 2, 4, and 6 weeks. Nightshade established at pea planting were removed at 2, 4, and 6 weeks. Nightshade emerging after pea establishment did not reduce yields. Pea yields were reduced when nightshade interference occurred for the first four weeks. The yield reduction was caused by fewer peas being produced per plant. In the greenhouse experiment, the proportion of nightshade and peas planted in 38 L pots and nitrogen levels were varied. Nitrogen had a significant effect on nightshade competitiveness with peas.
EFFECT OF GENOTYPE, PLANTING DATE AND LEVEL OF MOISTURE AT HARVEST ON THE YIELD AND QUALITY OF GREEN-SHELLED BEANS
Authors: Beaver James , Fernandez Fred
Published: April 2024

In Puerto Rico, harvesting beans (Phaseolus vulgaris) near physiological maturity enhances the value of the crop. Green-shelled beans are generally harvested 60-65 days after planting avoiding disease and pest problems that occur at the end of the growing season. It is also suited for multiple cropping and intensive rotations. Field experiments were conducted on the northern (Isabela) and southern (Fortuna) coastal plains of Puerto Rico to measure the effect of genotype, planting date and level of moisture of the seed at harvest on the yield and quality of green-shelled beans. The most adapted genotypes produced more than 5000 kg/ha of whole pods and 2200 kg/ha of green-shelled beans at both locations and growing seasons. Genotypes having different seed types were found to produce acceptable green-shelled yields. Whole pod yields were lower when harvested at the semi-dry stage than at the stage of development recommended for harvesting green-shelled beans. However, bean yields were similar when harvested at the green-shelled and semi-dry stages of development.
YIELD AND YIELD COMPONENTS ANALYSIS OF PEA CULTIVARS IN RESPONSE TO PLANTING DATE
Authors: Alsadon Abdulla A. , Khalil Safwat O.
Published: April 2024

Lincoln and Rondo pea cultivars were evaluated under three planting dates, early (Oct. 21 or 22) midseason (Nov. 4 or 5) and late (Nov. 18 or 19) in 1989-90 and 1990-91 seasons, respectively.

While Rondo cv was superior in pod weight, pod length and 100- green seed weight, Lincoln cv. produced higher number of pods / plants and higher seed: pod ratio. Both cultivars had equal productivity. Early Planting was best for most of the studied traits. Pod weight and number of seeds / pod were not significantly affected by date of sowing. However, both traits were reduced with late planting.

During the growing season, yield increased up to the fourth harvest. However, in midseason and late planting, yield peaked by the second harvest. High correlations among yield attributes were obtained. These correlations were not affected by planting date.
DIURNAL FLUCTUATION OF CARBOHYDRATE CONCENTRATION OF YOUNG WATERMELON PLANTS AS AFFECTED BY LIGHT QUALITY
Authors: Hatt Heather , Decoteau Dennis R.
Published: April 2024

Young watermelon (Citrullus lanatus cv. Sugar Baby) plants were treated with end-of-day (EOD) Red (R), Far-red (FR), and Far-red followed by Red (FR/R) light for 15 minutes. Control plants had no EOD light treatment. FR light treatments influenced plant growth and development (i.e., petiole elongation, internode elongation, and reduced petiole angles). Plants were sampled every 4 hours for a 24 hour period from each light treatment. Tissues (petioles, leaves, stems, and cotyledons) were analyzed from each treatment and sampling time combination for soluble carbohydrate and starch concentrations. Results suggested that carbohydrate concentration, distribution, and diurnal fluctuation were affected by EOD light quality treatments. Petioles of FR treated plants contained the greatest concentration of glucose, fructose and total soluble carbohydrates, and the least concentration of stachyose and starch. Stems of FR treated plants had the least concentration of total sugars and starch. Petioles of R treated plants contained the greatest concentration of stachyose and the least concentration of glucose. The changes in concentration of the storage carbohydrate (starch) and breakdown products (fructose and glucose) of the translocated sugar (sucrose) may be correlated to active growth of petioles and stems in response to light quality.
SEEDLING GERANIUM GROWTH AND FLOWERING RESPONSES TO UNICONAZOLE
Authors: Grindstaff Tracy L. , Starman Terri W. , Cerny Teresa A.
Published: April 2024

New cultivars of seedling geraniums are bred for compact growth habit to be grown in plugs, cell packs, or 0.4-liter pots. Chlormequat chloride (CCC) is recommended for use on these cultivars grown in 0.4-liter pots to increase the branching and green color of leaves. The objective was to determine concentration of uniconazole (UNI) foliar spray and medium drench and to compare the efficacy of UNI with CCC at 750 mg·liter-1 on Pelargonium × hortorum cvs. Red Elite (RE) and Multibloom Scarlet (MS). Growth retardants were applied 5 weeks after sowing when plants had five leaves 2.5 cm in diameter. Three plant size variables (height, width, and peduncle length) and 3 flowering variables (flower diameter, days to flower, and bud number) were measured. The experiment showed that CCC reduced all size variables in RE and MS compared to the controls. UNI drenches at applications of 0.05 and 0.025 mg a.i./pot controlled size variables similar to CCC drenches in RE. In MS, all UNI drenches decreased plant size variables more than CCC with one exception. UNI sprays did not reduce size like CCC sprays on RE. UNI spray controlled size variables of MS similar to CCC when administered at 20 mg·liter-1. CCC reduced flower diameter more than UNI in both cultivars. In MS, UNI drench reduced days to flower compared to CCC. Both growth regulators increased bud number of MS compared to the control.
SEWAGE SLUDGE COMPOST'S CUMULATIVE EFFECTS ON CROP GROWTH AND SOIL PROPERTIES
Authors: Bevacqua Robert F. , Mellano Valerie J.
Published: April 2024

Onion (Allium cepa cv. Spanish Sweet Utah), lettuce (Lactuca sativa cv. Black Seeded Simpson), snapdragon (Antirrhinum majus cv. Sonnet Yellow), and turf (Festuca arundinacea cv. Marathon) were grown twice annually (spring and fall) on a San Emigdio sandy loam (course-loamy, mixed calcareous thermic, Typic Xerorthents) soil for two years that was treated with a cumulative total of 0, 37 and 74 MT/ha of sewage sludge compost from San Diego. The soil received two compost treatments each year and crops were planted within a week of compost incorporation. Crop growth was monitored and the results of the fourth or final planting will be presented. Seedlings of onion, snapdragon and lettuce transplanted to compost treated plots displayed more vigorous establishment than those in the control plots. Compost treatments produced higher yields of onion, turf and lettuce. Snapdragon yield was not affected by compost treatment. Significant changes in pH, CM, EC, and various nutrients were noted upon the analysis of the soil.
EFFECT OF AMENDING SOIL WITH MUNICIPAL SOLID WASTE (MSW) COMPOST ON YIELD OF BELL PEPPER AND EGGPLANT
Authors: Ozores-Hampton Monica , Bryan Herbert H
Published: April 2024

At two locations MSW was incorporated into the soil at 0, 90, 134 t/ha. Bell pepper and eggplant were transplanted into the field. Total marketable and large size fruit yield of eggplant were significantly higher in the MSW compost treatments than in the control. There were no significant differences in the mean size of marketable and large size eggplant fruit. Total marketable bell pepper yield tended to be higher in the MSW compost treatments than the control, but differences were not significant. MSW compost treatments resulted in significantly higher large pepper yield than the control, but mean fruit size was not affected by MSW.. In general plants with MSW compost yielded higher than the control.
LONG-DURATION EXPOSURE FACILITY (LDEF) OF NASA HAS LITTLE DELETERIOUS EFFECT ON CUCUMBER SEEDS
Authors: Wehner Todd C.
Published: April 2024

Cucumber (Cucumis sativus L.) production during sustained space missions depends on reliable seed storage and seedling growth in a production facility aboard the space vehicle. NASA sent a space platform, the LDEF, into earth orbit aboard the shuttle Challenger in April 1984. It was retrieved by the shuttle Columbia in January 1990. Cucumber seeds were stored with several levels of protection (constituting 6 treatments) aboard LDEF. Field tests were run at Clinton, NC with 2 seasons, 4 replications, 4 harvests, and 12 seed treatments (including 6 controls). Traits measured included seedling emergence and abnormalities, vine growth, flowering and yield. The largest effects were for percentage emergence, where the seeds receiving the least protection (little cover, vented to outer space) had 40% emergence compared with 80% for the control. There were a large number of seedling abnormalities in the vented treatments, with cotyledon mutants most common, followed by true leaf, then stem. The least protected treatment had 75% abnormalities (mostly minor), compared with 30% for the control. However, plants recovered rapidly, so yield, earliness, percentage cull fruits, and disease incidence were not significantly affected by storage on LDEF.
CHARACTERIZATION OF POPULATION CO2 EXCHANGE OF POTATO GROWN IN KSC'S BIOMASS PRODUCTION CHAMBER.
Authors: Stutte G.W. , Wheeler R.M. , Peterson B.V.
Published: April 2024

To characterize CO2, exchange, potatoes (Solanum tuberosum cv. Norland) were grown for 90 and 105 days in KSC's Biomass Production Chamber, a 116 m-3 closed cuvette, with 0.5 strength modified Hoagland solution using recirculating NFT culture, 12/12 photoperiod, 1000 μmol mol-1 CO2, and approximately 900 μmol m-2 s-1 PPF from HPS lamps. Canopy gas exchange responses to CO, concentration, light intensity, and photoperiod were experimentally determined. CO, exchange showed a linear response to PPF (up to 1100 μmol m-2 s-1 max.) and a light compensation point of about 150 μmol m-2 s-1. Sustained exchange rates of >45 μmol CO2, m-2 s-1 were obtained 50 days after planting. CO2 saturation was approximately 1200 μmol mol-1 CO2 with a compensation point < 100 μmol mol-1. A dark cycle of less than 4 hours resulted in a rapid, continuous decrease in C02 exchange rate which was partially reversed by a 12-hour dark cycle. There was a weak correlation CO2 exchange and leaf starch concentration at the end of the dark cycle.
SELECTION AND INTRODUCTION OF WOODY LANDSCAPE ORNAMENTALS AT THE UNIVERSITY OF GEORGIA
Authors: Dirr Michael A. , Armitage Allan M. , Lindstrom Orville M.
Published: April 2024

The Department of Horticulture has introduced over 20 new plants into the Georgia and southern nursery trades. The program serves as a conduit for evaluating and distributing plants from the U.S. National Arboretum, Arnold Arboretum, individuals and nurseries. Propagation requirements and cold hardiness estimates are determined for most of the potential introductions. Cooperating nurseries provide real-world assessments of container and field cultural criteria. Further, plants are tested under field conditions at the Department's research farm. Plants are promoted through lectures, articles, and distribution to any interested Georgia nursery. Numerous trade, popular, and refereed articles were spawned from the program. Selected plants have been provided to commercial tissue culture labs for stock increase.

To date, the University has realized no financial return. A genuine need exists to generate income from royalties to sustain and enlarge the program.

A list of the Georgia introductions will be available to all participants and several of the more notable introductions will be discussed.
BIOLOGICAL SEED TREATMENTS USING TRICHODERMA HARZIANUM FOR HORTICULTURAL CROPS
Authors: Taylor A. G. , Harman G. E. , Nielsen P. A.
Published: April 2024

Biological seed treatments provides an alternative to chemical seed treatments or may also be used in combination with chemicals for effective control of plant pathogens. Seed treatment technologies are an important component of pest management, especially for effective biological control. Several seed treatments have been developed and evaluated to increase efficacy of the bioprotectant, Trichoderma harzianum, including 1) suspending the bioprotectant in a binder for a slurry application, 2) use of film coating technology, termed liquid coating, 3) combination of physiological treatments such as priming with the biological and 4) a dry planter box formulation. A laboratory bioassay consisting of sowing cucumber seeds in Pythium or other pathogen infested soil has shown that seed treatment technologies can enhance the efficacy of the bioprotectant. Field research has been conducted over four growing seasons on standard sugary and sh2 sweet corn. In general, emergence from seeds treated with Trichoderma by the described methods was comparable to seeds treated with chemical pesticides. Furthermore, plant growth was enhanced in several field studies.
CONSERVING AND USING CROP GENETIC RESOURCE COLLECTIONS: THE CONTRIBUTION OF PUBLIC SECTOR PLANT BREEDERS, GENETICISTS, & CURATORS
Authors: Merrick Laura C.
Published: April 2024

The number and status of germplasm collections associated with plant breeding and applied genetics programs at U.S. public sector institutions [i.e., at both state (SAES) and federal (USDA ARS) agricultural experiment stations] was assessed from a resource conservation perspective via a questionnaire sent to over 1300 people who have been involved with the use or conservation of crop genetic resources in research, preservation, administration, or advisory capacities. The latter so-called working collections typically emphasize use rather than conservation of germplasm, while in turn preservation is one of the primary functions of genebank collections such as those managed by USDA's National Plant Germplasm System. A major objective of the project was to assess the vulnerability of germplasm in working collections to being discarded or left in limbo when breeding programs are discontinued. An evaluation was made of “who is breeding or conserving what crops and where” in order to determine patterns of investment in genetic improvement of major vs. minor crops, as well as in federal- vs. state-based activities. Such differences may be relevant when devising plans to improve germplasm conservation and use. Specific examples of breeding and conservation activity relating to vegetable crops will be compared to that of other types of crop commodities.
PREDICTING FILM PACKAGING NEEDS FOR LIGHTLY PROCESSED FRUITS AND VEGETABLES
Authors: Cameron Arthur C.
Published: April 2024

Packaging films are currently used to modify the environment surrounding most lightly processed fruits and vegetables. For some produce, it has been demonstrated that low O2 and/or elevated CO2 will maintain quality and extend shelf life. For others, reduction of water loss may be of more importance. We have developed a model which can be used to design packages for concurrent modification of both O2 and H2O. The effect of variation in respiration from one batch of product to another on resultant O2 levels in packages will be discussed in relation to the risk associated with excessively low levels of package O2. Such low levels of O2 not only impair the quality of the product but provide a favorable environment for development of dangerous human pathogens. There is also risk associated with inadvertent increases in temperature during handling and marketing. For environmental considerations, it is desirable to use films which can be reused and/or recycled. The impact of these variables on the prediction of appropriate films and designs for packaging will be discussed.
EDIBLE COATINGS FOR LIGHTLY PROCESSED FRUITS AND VEGETABLES
Authors: Baldwin Elizabeth A. , Nisperos-Carriedo Myrna O.
Published: April 2024

Minimal processing is defined as handling, preparation, and distribution of agricultural commodities in a fresh state. Cutting fresh produce results in injury, cell leakage and accelerated perishability. The presence of an artificial barrier to gas and moisture diffusion ideally would reduce moisture loss, decrease levels of internal oxygen, increase internal carbon dioxide, reduce respiration rate and wound ethylene production, and delay ripening/senescence. In practice, the degree to which the above factors can be altered for a given commodity depends on species, cultivar, surface-to-volume ratio, respiration rate, etc. An edible coating, as an artificial barrier, is made from renewable resources, is biodegradable and can be used as a carrier for antioxidants, artificial colors, flavors, growth regulators, enzyme inhibitors and preservatives. The cutting of produce, however, results in a high moisture surface which presents special problems for coating adherence and microbial control. Recent research on coating of cut mushrooms, celery, apples, pears and peeled carrots, to maintain texture and reduce discoloration, with edible composite coatings will be discussed.
EFFECT OF TRAINING SYSTEM AND IN-ROW SPACING ON EARLY PERFORMANCE OF APPLE.
Authors: Schupp James R.
Published: April 2024

A trial was established in 1989 to evaluate the performance of `McIntosh'/M.26 apple trees trained to central leader, Y-trellis or vertical axe training systems. In-row tree spacings were 1.2, 1.8 or 2.4m with the vertical axe and 1.8, 2.4 and 3.0m with the central leader and Y-trellis trees. Treatments were arranged as a split-plot design with system as the main plot treatment, in-row spacing as the sub-plot treatment, and six replications. In 1991, the vertical axe trees had higher yields than the other two systems. System had no effect on yield in 1992. Trees at 1.8m produced greater yield/ha than trees at 2.4m. Y-trellis trees produced more large fruit than central leader trees, while vertical axe trees produced the fewest large fruit. Trees at 1.2m produced fewer large fruit than at 1.8 or 2.4m in the vertical axe systems. In-row light interception increased as tree spacing dropped from 2.4 to 1.8m. Vertical axe trees intercepted more light within the row than the other two systems.
EFFECTS OF THREE WATERING REGIMES ON COLD HARDINESS OF TWO RHODODENDRON CULTIVARS
Authors: Anisko Tomasz , Lindstrom Orville M.
Published: April 2024

Plants of two rhododendron cultivars, `Catawbiense Boursault' and `Yaku Princess', were subjected to three watering regimes: 100, 200, and 300 ml of water per 1-gallon-container, applied 4 times a week between August 24 and October 2, and twice a week between October 2 and December 18. A freeze test was conducted on January 11. Injury to leaves, stems, and vegetative buds was visually evaluated after 4 and 11 days of incubation at room temperature. Leaves of `Catawbiense Boursault' plants under “100 ml” watering regime were significantly less injured at temperatures between -10 and -16°C than leaves of plants under “200 ml” and “300 ml” regimes. Stems of this cultivar under “100 ml” regime were significantly more injured at temperatures -28 and -30°C than stems of plants under “200 ml” and “300 ml” regimes. Differences in the injury rating for `Yaku Princess' plants were not significant for either leaves or stems. Vegetative buds of both cultivars were not injured even at the lowest test temperature, i.e. -30°C.
PATTERNS OF NITROGEN UPTAKE BY GREENHOUSE ROSES.
Authors: Cabrera Raul I. , Evans Richard Y. , Paul J.L.
Published: April 2024

A recirculating nutrient solution system was constructed for studying the N uptake by roses in relation to the developmental stage of the crop and light conditions. N and water uptake were measured at 2 to 3 day intervals for a period of 1 year. Daily PPFD was also recorded.

N uptake rates followed a cyclical pattern that was related to shoot development and harvest, but independent of transpiration rate. The N uptake rate changed fourto five-fold during a single cycle of flower shoot growth (e.g., 29 to 146 mg N plant-1 day-1). The lowest N uptake rate occurred when the shoot elongation rate was at its maximum. The highest N uptake rate occurred at about the time the flower shoot reached commercial maturity. Following harvest, the uptake rate remained high for several days, even though there was no shoot growth during that time. There were also seasonal changes in N uptake. The average daily plant N demand was about 30 and 60 to 70 mg plant-1 day-1 during the winter and summer months, respectively. The total annual plant N uptake was in close agreement with the yearly plant N demand calculated for container grown roses.
PHYLOGENETIC RELATIONSHIPS OF VERNONIA BASED ON SEED PROTEIN ELECTROPHORETIC VARIATION.
Authors: Jeyaretnam Benjamin , Phatak Sharad C , Wetzstein Hazel Y.
Published: April 2024

Twenty accessions of Vernonia galamensis (Cass.) Less. from six subspecies were studied to develop a phylogram based on the seed protein profiles on one-dimensional (SDS-PAGE) gel electrophoresis. Soluble protein was extracted with 50 mM Tris-HCl buffer. Resolution factor values (Rf) and molecular weights of different protein profiles were estimated. The percentage similarities among different accessions were calculated and a consensus phylogram was derived using PAUP analysis. Almost all soluble proteins showed a moderate mobility (Rf. 0.2 to 0.6) and resolved as four clusters with varying number of classes. Variety ethiopica was observed to have greater mutational differences from other varieties of same subspecies galamensis and other subspecies. Variety petitiana showed greater genetic deviation to varieties galamensis, australis and nairobensis of the same subspecies galamensis than among the later three. Mutational distances between Subspecies gibbosa, mutomoensis and afromontana were similar.
AN INFORMATION INDEX FOR EFFICIENT ANALYSIS OF GENETIC RELATIONSHIPS BASED ON MOLECULAR MARKER DATA
Authors: Tivang Jan G. , Nienhuis Jim
Published: April 2024

Variation for molecular markers (RFLPs and RAPDs) can be used to measure genetic relationships among genotypes. The theoretical minimum number of polymorphic bands needed to discriminate among 100 genotypes is seven (27=128). However, due to redundancy and lack of independence, larger numbers of polymorphic bands are usually required to separate genotypes. This problem can be addressed by using an index that will measure the number of discriminations among the genotypes for a given probe or primer. We have developed an information index that can be used to rank either enzyme-probe or RAPD primer combinations with regard to their ability to discriminate among genotypes. The index has great utility in selection of the most efficient enzyme-probe or RAPD primer combinations in germplasm screening. In addition, the index can also be used to estimate the sampling variance of polymorphic bands without the need for the computer intensive bootstrap procedure.
USE OF MINOLTA SPAD 502 CHLOROPHYLL METER FOR SELECTION AND EVALUATION OF SWEET CORN
Authors: Miles Carol A. , Minotti Peter
Published: April 2024

Sweet corn genotypes were selected, recombined in a half-sib fashion, and evaluated for yield performance at the NYSCALS Experiment Station at Freeville, NY. The objectives of this study were to identify selection criteria associated with N efficiency. Selection and evaluation parameters included chlorophyll readings with the Minolta SPAD 502 chlorophyll meter. The Minolta chlorophyll meter is a rapid, non-destructive method of determining leaf chlorophyll status, and may be an effective tool for evaluating plant N status and thus yield. It is of interest to evaluate plants early in a breeding program for yield potential. Chlorophyll readings were measured at the fifth-leaf stage and at maturity. In 1991, chlorophyll readings were significantly correlated to N concentration (%) and total N content (gm) of the fifth-leaf. Chlorophyll readings measured at the fifth-leaf stage and tasseling were correlated to primary ear fresh and husked weight in 1992. Based on these results, chlorophyll readings were an effective assessment of N status and ear yield.
YIELD OF WATERMELON AS INFLUENCED BY PLANT SPACING
Authors: NeSmith D. Scott
Published: April 2024

Watermelon (Citrullus lanatus (Thunb.) Matsum & Nakai) cultivars Starbrite and Crimson Sweet were grown during 1991 and 1992 in 1.5 m wide rows at plant spacings of 0.9 m, 1.5 m, or 2.2 m. Total fruit yield, marketable fruit yield, fruit size distribution, and estimated gross returns were determined for the different spacing treatments. Total and marketable fruit yields were greater overall for `Starbrite' than for `Crimson Sweet'. With the exception of 1991 `Crimson Sweet' yields, marketable fruit yields per unit land area increased 29% to 34% as plant spacing was decreased from 2.2 m to 0.9 m. The yield component contributing the most to increased yields with higher density plantings was increased fruit number per unit land area. Average fruit weight responded only slightly to decreased plant spacing. Fruit size distribution on a relative frequency scale was stable regardless of plant spacing or production year. The potential for increasing gross returns per unit land area exists by increasing watermelon plant populations beyond the current Georgia recommendation of 2500 to 3000 plants ha-1.
PHOTOSYNTHETIC AND GROWTH RESPONSES TO CANOPY MANIPULATION OF TITAN' RED RASPBERRY
Authors: Fernandez Gina E. , Pritts Marvin P.
Published: April 2024

It has been suggested that in red raspberry, primocanes and floricanes compete with one another for light and/or photosynthetic products, under most management systems. In 1991, a field study was initiated to determine the effects that altering this natural balance between primocanes and floricanes would have on leaf photosynthetic rates and growth components. Fourteen treatments were applied to a mature planting of `Titan' red raspberry in the spring of 1991. Treatments included partial or entire canopy shading and/or removal of primocanes, floricanes or fruit. All treatments were removed at the end of the 1991 growing season. Photosynthetic and growth data were collected over a two-year period. Both shading and removal of growth had profound effects on data in both years. In general, removal of primocanes floricanes or fruit enhanced growth of the remaining form(s) of growth. However, this effect was negated if all or part of the canopy was shaded. Floricane photosynthesis was highest in the presence of fruit preceding and during harvest. Treatments had an effect on primocane photosynthetic rate only after fruiting. In 1992, shading treatments applied the previous year resulted in lower primocane photosynthetic rates than those treatments which were not shaded. The data generated from this study will help us describe the complex relationship between primocanes and floricanes.
DIFFERENTIAL GENE EXPRESSION DURING VERNALIZATION FOR FLORAL INDUCTION OF RAPHANUS SATIVA
Authors: Strefeler Mark S. , Erwin John E. , Pierson Gerald
Published: April 2024

Previous studies on low temperature induction of flowering in Japanese radish, Raphanus sativa L., revealed that `Chinese Radish Jumbo Scarlet' was a cold obligate cultivar. `Chinese Radish Jumbo Scarlet' responded quantitatively to the number of days exposed to vernalizing temperatures (6 C). Fifteen percent of the plants were induced to flower when exposed to 6 C for 5 days. This response increased proportionally to 100% induction when plants were vernalized at 6 C for 30 days. This type of response allowed us to examine the changes in gene expression over time during the vernalization process.

cDNA libraries were constructed from non-vernalized radish seedlings and seedlings vernalized for 1, 5, 15 or 30 days. Differential screening of the cDNA libraries was carried out to determine changes in gene expression related to the vernalization or induction processes. Up and down regulation of gene expression and activation or deactivation of genes during the vernalization process will be discussed. The ultimate goal of this project is to elucidate the processes involved in floral induction and how these processes are initiated by exposure of plants to vernalizing temperatures.
ALLOZYME DIVERSITY IN THEOBROMA CACAO
Authors: Ronning C.M. , Schnell R.J.
Published: April 2024

Theobroma cacao is a morphologically diverse species. To understand variation within species, gene diversity estimates for a germplasm collection were calculated from allozyme data. Of nine enzymes assayed, six enzymes encoded by nine loci were found to be polymorphic. The population was subdivided into subpopulations in two ways: by geographical origin and by morphological type. Total gene diversity was similar to that of other tropical, outcrossing, perennial species. Most of this diversity was found within, rather than between, subpopulations; the differentiation was higher among types than among origins. Caribbean and Central American clones were more closely related to each other, and distinct from, South American clones. Two clusters were formed when grouped by type: Trinitario/Criollo and Forastero/intergroup hybrids. This information may be useful to the breeder, as well as for the maintenance of genetic diversity within a germplasm collection.
ANALYSIS OF HAWAII AGRICULTURE AFTER `INIKI' HURRICANE.
Authors: Smith-Kayode Timi , Thompson Richard
Published: April 2024

Sustainable production system encompassing Macademia, Sugar, Coffee, Fruits and Flowers a hall mark of Hawaiian Agriculture is now threatened by hurricane and rain storms. Concerns for crop losses and set back in agribusiness are beign intensively discussed against the background of future diversifications of operation and investment.

Findings from post 'Iniki' hurricane study of losses through survey of Hawaii grown economic commodities produced on the Island of Kaui are contained in this paper.

Highlights showed that banana and papaya farming systems have the highest recovery potential. The impact on fruit processing industries is also discussed.
GROWTH, SALT TOLERANCE AND MANNITOL ACCUMULATION IN CELERY
Authors: Kann Susan C. , Everard John D. , Loescher Wayne H.
Published: April 2024

Mannitol, which in celery is a primary photosynthetic product, has been implicated along with other polyols in stress tolerance mechanisms as a possible osmotic regulator, compatible solute and free radical scavenger. We have characterized the growth of salt stressed celery, determined the extent of salt tolerance and showed a correlation between mannitol accumulation and salt tolerance.

Six, 8 and 12 week-old pot grown celery (Apium graveolens L.) plants of two cultivars were irrigated with up to 500 mM NaCl for 3.5 and 7 weeks. After 7 weeks, 12 week-old `Giant Pascal' plants showed three major responses: 1) shoot wet wt increased as much as 30% at 25 mM NaCl but root wet wt decreased; 2) plants tolerated 500 mM NaCl, although at a severely reduced growth rate; 3) as salt concentrations increased mannitol concentrations increased in roots, leaves and petioles, while sucrose, the other photosynthetic product in celery, decreased Although all ages of both cultivars tolerated the highest salt concentration used, the beneficial effect of 25 mM NaCl occurred only in 8 and 12 week-old `Giant Pascal'. Root wet wt was reduced in all salt treated plants, irrespective of age or cultivar.

Regardless of age, cultivar and length of treatment, celery tolerated high salinity and sometimes even increased wet wt at low salinity. Mannitol accumulation and the ratio of mannitol to sucrose were both positively correlated with salt tolerance
EFFECTS OF CO2, ON LEAF STOMATAL CONDUCTANCE AND PRODUCTION OF LETTUCE AND RADISH
Authors: Mackowiak C.L. , Wheeler R.M. , Yorio N.C.
Published: April 2024

Lettuce (cv. Waldmann's Green) and radish (cv. Giant White Globe) plants were grown hydroponically with a 18-hr photoperiod and 300 μmol m-2 s-1 PPF. Treatments consisted of 400, 1000, 5000 and 10000 μmol mol carbon dioxide (CO2). Leaf stomatal conductance was monitored with a steady-state porometer across one diurnal period at 21 days and all plants were harvested at 25 days. Conductance at 400 and 10000 was > 1000 μmol mol-1 for lettuce and conductance at 5000 and 10000 was > 1000 and 400 μmol mol-1 CO2 for radish. Carbondioxide treatments having the lowest leaf conductances also resulted in the highest yields, viz. 1,000 μmol mol-1 CO2 for radish and 5000 μmol mol-1 CO2, for lettuce. Dark-period conductance was higher at 5000 and 10000 μmol mol-1 CO2 compared to 400 and 1000 μmol mol-1 CO2. The higher dark-period conductances were 70% of the light-period rates for lettuce and 30% for radish. Water use efficiency (WUE) (g biomass kg water-1) was lowest at 400 μmol mol-1 CO2 for both lettuce and radish and was highest at 1000 μmol mol-1 CO2 for lettuce and 5000 μmol mol-1 CO2 for radish. The results suggest that WUE was improved with moderate CO2 enrichment but declined at very high concentrations, i.e. 10000 μmol mol-1 for lettuce and radish.
GROWTH AND WATER STRESS RESISTANCE OF VIBURNUM PLICATUM VAR. TOMENTOSUM IN PINE BARK-AMENDED SOIL.
Authors: Wood C.B. , Smalley T.J. , Rieger M. , Radcliffe D.E.
Published: April 2024

Container-grown Viburnum plicatum Thunb. var. tomentosum (Thunb.) Miq. were transplanted on May 1 into tilled plots, tilled plots amended with aged pine bark, and untilled unamended plots (control) within a greenhouse. Plants were irrigated weekly for three months prior to drought initiation. Root growth, shoot growth, leaf water status, and leaf expansion rates were measured to determine whether tilling or site amending enhanced drought stress resistance. Prior to drought initiation amended treatments had the greatest new root length. New root dry weight of amended plots was 57% greater than controls and 32% greater than tilled plots. Mean root system diameter was 111 cm, 87 cm, and 61 cm for amended, tilled, and control plots, respectively. The mean ratio of new root length (cm) to leaf area (cm2) was 5.3:1 in amended plots, 2.2:1 in tilled plots, and 1.7:1 in controls. During the drought, midday relative leaf water content was lowest in controls, while the rate of leaf expansion was greatest in tilled plots. Changes in soil moisture were monitored using time domain reflectometry. Control plots had higher volumetric water content; however, moisture release curves suggest that tilled and amended plots contained more plant available water.
COMPARATIVE FLOOD TOLERANCE OF BIRCH ROOTSTOCKS
Authors: Ranney Thomas G. , Bir Richard E.
Published: April 2024

Survival, growth, and physiological responses were compared among flooded and non-flooded container-grown trees of `Whitespire' Japanese birch (Betula platyphylla var. japonica `Whitespire') grafted onto each of four rootstocks: paper birch (B. papyrifera), European birch (B. pendula), river birch (B. nigra) and Japanese birch. Separate studies were conducted in the fall of 1991 and spring of 1992. Under flooded conditions, of up to 44 days, plants on river birch rootstocks typically had one of the greatest rates of photosynthesis Pn, stomatal conductance and, in certain cases, greater mean shoot growth rates and survival. Plants with European birch rootstock had similar survival rates to plants with river birch rootstocks, but they did not maintain as high Pn under prolonged flooding, they had less root and shoot growth, and a greater number of abscised leaves under certain conditions. Paper and Japanese birch were the two taxa found to be most sensitive to flooding and shared the ranking of lowest survival rate following flooding. These results demonstrate that flood tolerance of 'Whitespire' birch can be considerably enhance when grafted onto river birch rootstock.
IMPROVED GROWTH OF PECAN AND ORNAMENTAL PEAR TREES IN CONTAINERS WITH WATER RESERVOIRS
Authors: Tilt Ken , Goff William , Olive John , Shumack Ronald
Published: April 2024

Growth of pecan (Carya illinoensis (Wangenh.) C. Koch `Melrose') and pear (Pyrus calleryana Decne. `Bradford') trees in the nursery was greater in containers designed to hold water in the lower portion. The water-holding reservoir was obtained either by placing 76 liter containers in a frame holding water to a depth of 5 cm, or by using containers with drainage holes 5 cm above the bottom. The continuous waterlogging at the bottom of the containers resulted in root pruning and root death in the lower portion of the containers, but roots grew well above the constantly-wetted zone. Fresh weight of tops, caliper, and plant height were all greater after two growing seasons in the containers with water reservoirs compared to similar containers with no water reservoirs.
A HEAT BALANCE TECHNIQUE TO MEASURE THE MASS FLOW RATE OF WATER IN TREES
Authors: Lindsey Patricia , Chandra Sanjeev
Published: April 2024

An improved gauge to directly measure the mass flow rate of water in a tree is described. Principal components of the gauge are: an electric band heater wrapped around a section of the stem; an temperature controller that switches the current to the heater on and off so as to maintain a constant temperature rise across the heated section; and a timer to record the total time that the heater has been switched on. An energy balance shows the mass flow rate of water to be proportional to the time of operation of the heater. Experimental measurements of the flow rate of water in a tree using the gauge agreed well with its recorded loss in weight over a 24 hour period (<3%) except on extremely hot days (>40°C, >50%). Subsequent adjustments to the design of the gauge have corrected these measurement errors related to ambient environmental conditions. These include lowering the thermal capacity of the insulation covering the gauge, and leaving a sufficient portion of the stem below the gauge uninsulated, to ensure that water flowing in the stem warms up enough to reach ambient temperature before it enters the gauge.
QUALITATTVE VARIATION IN FLORIDA BLUEBERRIES
Authors: Lyrene Paul M.
Published: April 2024

Most genetic variation in blueberries is quantitative. However, after a decade of exploration among Florida's native blueberry populations and more than 100,000 seedlings grown in nursery plots, several qualitative variants have been found. An allele for anthocyanin-free foliage in Vaccinium elliottii is recessive to wildtype. A second recessive allele at a different locus in the same species depletes anthocyanin in the fruit but not the foliage. A recessive allele in V. ashei produces white, pink, or purple berries when homozygous, the color depending on the clone that is made homozygous for the allele. A dominant allele in V. darrowi produces pink fruit and is nonallelic with the fruit anthocyanin deficiency allele in V. elliottii. Two V. elliottii clones with a weeping to prostrate growth habit have been found in west Florida. This phenotype is maintained by clonal propagation, but its inheritance has not been determined. A V. ashei plant with compact growth habit transmits this phenotype to a small percentage of its F-1 progeny when crossed with most V. ashei cultivars.
EVALUATION OF RESISTANCE TO THE FLORIDA AND EGYPTIAN STRAINS OF ZUCCHINI YELLOW MOSAIC VIRUS IN WATERMELON AND RELATED GERMPLASM
Authors: Boyhan G.E. , Norton J.D. , Gudauskas R.T. , Abrahams B.R.
Published: April 2024

Six lines of watermelon or related germplasm were evaluated for resistance to the Egyptian strain of zucchini yellow mosaic virus (ZYMV-E). `Egun' had the highest level of resistance of the lines tested based on enzyme-linked immunosorbent assays and visual ratings. PIs 386025, 386026, and 494528 appear to have intermediate resistance.

PIs 386025 and 386026, both resistant to the Florida strain of ZYMV, were analyzed in crosses with 'AU-Producer'. No Mendelian ratios were evident, therefore generation mean analysis was used to evaluate this material.
ASSESSMENT OF RAPD'S IN CUCUMBER (Cucumis sativus L.)
Authors: Staub J. , Poetter K.
Published: April 2024

Very little information exists regarding linkages in cucumber. There are 5,460 pairwise combinations which could be tested among the 105 described genes. Linkage information is available for only 3.2% of these possible pairwise comparisons. Our research unit is involved with mapping isozymes, RFLP's and RAPD's.

We have used F2 and BC progeny to construct RAPD maps and have found that although polymorphisms are present in cucumber they are not remarkably more frequent than molecular polymorphisms found using RFLP's. For example, we screened 1051 primers and detected roughly 140 possible polymorphisms between two inbred lines. Assessment of F2 progeny segregations resulted in the identification of 70 usable polymorhphisms. Approximately 40 of those markers segregated in an expected 3:1 ratio. An additional 11 markers segregated in a 1:1 ratio. Using a threshold of 32 cM, eight linkage groups were identified containing a total of 37 markers. In another F2 population within and between laboratory results were compared to determine error rates (1 to 5%). Data from a third F2 population suggest that there may be loose phenotypic correlations between RAPD primers and the determinate character (r2 = 0.54) and sex expression (r2 = 0.68). These associations are being further characterized using BC1 and F2 progeny.
LINKAGE BETWEEN ISOZYME MARKERS AND DISEASE-RESISTANCE GENES IN CUCUMBER (Cucumis sativus L.)
Authors: Meglic V. , Dijkhuizen A. , Kennard W. , Havey M. , Staub J.
Published: April 2024

Two hundred F2 cucumber (Cucumis sativus L.) families from crosses between GY14 (U.S. processing type) and PI 432860 (long greenhouse type) and GY14 and PI 183967 (C. sativus var. hardwickii) were evaluated for allozyme polymorphisms. Polymorphisms were detected at Fdp2, Mdh3, Mpi1, Pep-gl, Pgm1, Idh2, Pep-pap and Per. Subsequently they were scored for resistance to anthracnose (Colletotrichum lagenarium), scab (Cladosporium cucumerinum) and angular leaf spot (Pseudomonas lachrimans).

Estimates of the recombination frequencies confirmed previously established linkage groups among allozyme markers (Knerr and Staub, 1992) and revealed new associations between allozyme loci and disease resistance genes. Scab appears to be tightly linked to and flanked by Fdp2 and Mdh3.
MICROPROPAGATION AND SOMATIC EMBRYOGENESIS OF SWEETPOTATO, EFFECTS ON PLANT GROWTH AND YIELD
Authors: Schultheis Jonathan R. , Collins Wanda W. , Cantliffe Daniel J.
Published: April 2024

Commercial sweetpotato fields are established with asexually derived propagules as either cut or pulled plants. Micropropagation and somatic embryogenesis were/are being investigated to improve seed production. Micropropagation of sweetpotato is utilized in California as part of its seed production program. Several studies have been conducted or are ongoing in North Carolina to evaluate the utility of micropropagation as part of its certification program. In 1992, yield was increased in `Beauregard' with micropropagated plants compared with plants that were derived from the North Carolina Certified Seed Program. However, there were no yield increases in four years of comparisons when `Jewel' and `White Delight' were micropropagated. A trend towards early bulking has consistently been observed in micropropagated `Jewel', `White Delight' and Beauregard. Early plant growth and yields of plants (`White Star') obtained from somatic embryos, micropropagation or vine cuttings were compared. Plants derived from somatic embryos grew slower and yielded less root weight than cut plants; however, more storage roots were obtained from plants obtained from somatic embryos indicating high yield potential if root bulking is achieved.
EVALUATION OF LUMINARES FOR HID LIGHTING
Authors: Langhans Robert W.
Published: April 2024

Luminares are the vehicle used to reflect and direct the light energy from the lamps to the desired area. There many companies manufacturing luminares and many different designs. The efficiency of the luminare can vary greatly from one design to another. We attempted to measure the efficiency of a selected group of luminares. The results were confusing as we will show and further investigations into this problem uncovered the major reasons for the discrepancies and difficulties in coming to a simple recommendation.
BLOOM THINNING OF PEACH AND NECTARINE WITH MONOCARBAMIDE DIHYDROGENSULFATE
Authors: Myers S. C
Published: April 2024

Increased fruit weight, advanced fruit maturity, increased shoot growth and greater flower bud formation are positively related to thinning severity and timing. Thinning at bloom shows greatest effects. Although costly, hand removal is the primary thinning method. Chemical means have been used but have had disadvantages and/or lack of industry support. A new compound, monocarbamide dihydrogensulfate, has been used on apple. Trials conducted on `Golden Queen' clingstone peach and `Fantasia' nectarine in New Zealand and on `Winblo' peach in Georgia suggest that this compound has significant potential for use in thinning stone fruit. An effective material rate (79-82% a.i. formulation) of 12 l/ha applied via airblast sprayer (calibrated delivery 1200 l/ha total volume) on peach resulted in a 56% reduction in flowers per limb cross-sectional area compared to unthinned controls when applied at full bloom. No phytotoxicity has been observed.
NEW CHEMICAL THINNERS FOR APPLES
Authors: Greene Duane W.
Published: April 2024

Several new compounds show promise as chemical thinners. Benzyladenine (BA) has been identified as one of the most effective on apples. It is especially useful on McIntosh and Empire but it also thins other cultivars such as Delicious, Golden Delicious, and Idared. It is active at concentrations as low as 50 mg·liter-1. BA thins most effectively when applied at the 10mm stage of fruit development. It increases fruit weight indirectly by reducing crop load, but it can also increase fruit weight additionally and independently of its effect on crop load. BA frequently increases flesh firmness and soluble solids, but it must come in direct contact with the fruit to do this. Fruit treated with BA store comparably to similar sized fruit treated with other chemical thinners. There appears to be no unusual long term effects when BA is used as the only chemical thinner for several consecutive seasons.