bluuebunny/crossref_metadata_2025 huggingface dataset:
EVALUATION OF SWEET CORN LINES FOR RESISTANCE TO NORTHERN LEAF BLIGHT AND THE SUGARY ENHANCER (SE) GENE.
Authors: Faber Andrea
Published: April 2024

In regions of sweet corn production in the U.S. and overseas epidemics of northern leaf blight (NLB) caused by the foliar pathogen Exserohilum turcicum are common. NLB can significantly decrease yields, and ear quality of susceptible and moderately susceptible sweet corn hybrids. Thirty-four BC2F7 sweet corn inbreds have been created from several crosses between field corn lines with various Ht resistance genes (Ht1, Ht2, Ht3, and HtN) and three high quality sweet corn inbreds homozygous for the sugary enhancer (se) gene. These gene when homozygous in sweet corn kernels increases sugar content at harvest and improves fresh ear quality and consumer appeal. Seedlings of the 34 different inbreds with either the Ht1, Ht2, Ht3, or HtN gene were inoculated with race 0 and 1 of E. turcicum, evaluated for lesion size, amount of leaf necrosis and hypersensitivity response to compare levels of NLB resistance in different genetic backgrounds. To ascertain which of these lines also contain the se gene, kernels from 20 DAP (days after pollination: typical fresh harvest maturity) and mature dry ears were freeze-dried, ground into powder, extracted and quantified for sugar content using a gas chromatograph. The lines with the best resistance to NLB and containing the se gene have been selected for release to breeders for the development of superior sweet corn hybrids.
MAPPING QUANTITATIVE TRAIT LOCI OF TUBER TRAITS IN DIPLOID POTATO (Solanum ssp.)
Authors: Freyre Rosanna , Douches Dave
Published: April 2024

Isozymes, RFLPs and RAPDs were utilized for Quantitative Trait Loci (QTL) analysis in diploid potato. The tuber traits under study were specific gravity and tuber dormancy. The two populations used, TRP132 (127 individuals) and TRP133 (110 individuals) have a common maternal parent and combine genomes of Solanum tuberosum (haploid), S. chacoense, and S. phureja. Specific gravity data was obtained from two seasons' field trials: 2 locations with 3 replications in 1990, and 1 location with 2 replications in 1991. The length of dormancy was evaluated in 1990. Both populations were characterized with 11 isozyme loci. Further studies focused on TRP133, characterizing it with 45 RFLP loci and over 60 RAPD loci. Statistical analyses were conducted to identify significant associations between markers and quantitative trait variation, epistatic interactions between markers, and their overall effect on the phenotypic variation for the traits. Significant QTLs have been localized on the potato genome through the use of molecular maps.
IMMUNITY TO INFECTION BY POTATO VIRUS Y AND POTATO VIRUS X IN A Solanum phureja - S. stentomum HYBRID POTATO POPULATION
Authors: Vallejo Roger L. , Collins Wanda W. , Young J.B. , Schiavone Rocco D.
Published: April 2024

A random sample of 6000 individuals from a recombinant Solanum phureja - S. stentomum hybrid population and 250 individuals of Solanum phureja were twice inoculated with potato virus Y (PVY) strain “o” using the air brush technique. Symptomless seedlings were field transplanted for further evaluation and 1508 seedlings were judged to be resistant to PVY (33%). At harvest, a mild selection pressure for tuber appearance was applied and 602 clones were selected.

Selected clones were re-evaluated for PVY resistance in the greenhouse: twice inoculated with PVY, tested by ELISA (Enzyme-linked immunosorbent assay), graft-inoculated with tobacco PVY infected scions, and subjected to a second ELISA test. To assess immunity to infection by PVY, the ELISA negative clones were bioassayed using tobacco cv. “Burley 21” as a plant indicator. We identified 224 PVY immune clones (4.8%).

Simultaneously, the first year PVY selected clones were twice inoculated with U.S. common strain of potato virus X (PVX). Clones free of PVX symptoms were tested by ELISA. Negative clones were re-inoculated with PVX and symptomless clones were re-tested by ELISA. To assess immunity to infection by PVX, negative clones were bioassayed using Gomphrena globosa as a plant indicator. We identified 7 immune (1.3%); 4 highly resistant and 4 resistant clones. Eight clones showed high levels of resistance to both PVY and PVX (high resistance to immunity).
EVALUATION OF YELLOW-FLESH POTATO CLONES
Authors: Haynes Kathleen G. , Sinden Stephen L.
Published: April 2024

For the yellow-flesh fresh market, potato clones with intense yellow-flesh and uniform size are desired. Twenty-five yellow-flesh clones were evaluated for individual tuber weight and tuber yellowness as measured by a reflectance colorimeter in replicated field trials in Presque Isle, Maine, in 1991. There were significant differences among clones for yellowness. Cluster analysis was used to group the clones by mean tuber weight in grams (MTWT) and variance of the mean tuber weight (VMTWT). Four clusters were identified. `Yukon Gold' was in a cluster by itself: MTWT=90 and VMTWT=86. Four clones formed a second cluster. The averages of these four clones were: MTWT=33 and VMTWT=3. MTWT was too small in the second cluster for these four clones to warrant further evaluation. Three clones formed a third cluster. The averages of these three clones were: MTWT=78 and VMTWT=43. The remaining 17 clones formed the fourth cluster. The averages of these 17 clones were: MTWT=54 and VMTWT= 11. The more intense yellow-flesh clones in the third or fourth clusters should undergo further evaluation for their fresh market potential.
GRAFT COMPATIBILITY AMONG CHESTNUT SPECIES CASTANEA SPP.)
Authors: Huang Hong Wen , Norton J.D. , Boyhan G.E. , Abrahams B.R.
Published: April 2024

Graft incompatibility of 3 chestnut Castanea spp. was studied. Nine American chestnut C. crenata Sieb. & Zucc and 15 Chinese chestnut C. mollissima Bl. cultivars used as scions were tested on rootstocks of Chinese chestnut. Interspecific grafts with 7 of 9 American chestnut selections had satisfactory graft compatibility on Chinese chestnut rootstocks (70%-100%), so did 6 of 8 Japanese chestnuts. Twelve and 10 out of 15 Chinese cultivars had high graft compatibility on Chinese chestnut rootstocks. Three Chinese cultivars with less than 50% success were probably due to very diverse genetic variation within one cultivar group of Chinese chestnuts. Spring grafts always had higher percent success rates than fall grafts. Graft incompatibility was not found to be related to the cambial isoperoxidase banding patterns in the present study.
LABORATORY EXERCISES ILLUSTRATING ORGANOGENESIS AND TRANSFORMATION USING CHRYSANTHEMUM CULTIVARS
Authors: Trigiano R. N. , May R. A.
Published: April 2024

A tissue culture laboratory exercise illustrating regeneration of whole plants from leaf segments of Chrysanthemum by organogenesis will be described. Using simple, common media, shoots can be generated in five weeks and rooted after an additional three weeks. Acclimatization of plants can be accomplished in a simple mistbed in the greenhouse. The exercise is adaptable to depict genotype differences among cultivars, optimization of shoot induction, effects of growth regulators, and experimental design. Callus is typically not formed during shoot formation; however, co-cultivation of leaf segments with a virulent strain of Agrobacterium tumefaciens produces callus autotrophic for growth regulators. Co-cultivation with a strain of disarmed A. tumefaciens harboring a NPTII construct affects regeneration of plants resistant to kanamycin.
SOMATIC EMBRYOGENESIS IN ORCHARDGRASS
Authors: Gray P. J. , Trigiano R. N , Conger B. V.
Published: April 2024

Morphologically-faithful somatic embryos, as well as embryogenic calli, emerge directly from cultured leaf bases of selected orchardgrass clones. The highly embryogenic clone `Embryogen-P', released by the University of Tennessee, can be maintained in greenhouse pots as a ready source of material for laboratory exercises. To initiate embryogenic cultures, the basal 2 cm of the innermost three leaves are split in half longitudinally, surface disinfested in 25% bleach solution with a drop of detergent for 2 min, then rinsed twice in sterile water. The leaf halves are cut crosswise into 3-5 mm sections, which are placed on solidified Schenk and Hildebrandt's medium containing 3% sucrose and 30 μM dicamba. Cultures are incubated in dark After 3-6 weeks, small white somatic embryos grow directly on leaf surfaces and friable white embryogenic callus emerges from cut edges or from within leaf sections. Laboratory exercises to be described include a gradient embryogenic response observed in leaves and a unique “split leaf experimental design that is useful for decreasing experimental variation.
A LABORATORY EXERCISE TO DEMONSTRATE DIRECT AND INDIRECT SHOOT ORGANOGENESIS FROM LEAVES OF TORENIA FOURNIERI
Authors: Bridgen Mark P. , Spencer-Barreto Madeleine
Published: April 2024

Plant cell cultures have the ability to regenerate roots, shoots, leaves, and flowers de novo. The production of adventitious shoots in vitro is easy to control on Torenia fournieri (Wishbone Flower). Direct shoot organogenesis is possible to obtain from leaf explants without an intervening callus phase. Leaf explants should be placed on a Murashige and Skoog (MS) basal medium with 6-benzylaminopurine (BAP) levels from 2.5-5 mg/1 and indole-3-butyric acid (IBA) at 0.1 mg/liter for direct shoot organogenesis. If leaf explants are placed on a MS medium with 1 mg 2,4-dichlorophenoxyacetic acid (2,4-D) per liter, callus formation will occur. If the callus is subcultured onto a MS medium with 0.5-1.0 mg BAP per liter and 0.1 mg IBA per liter, indirect shoot organogenesis will occur.
PROGRESS IN BIOTECHNOLOGICAL MANIPULATION OF CITRUS ROOTSTOCKS
Authors: Gmitter Frederick G.
Published: April 2024

Citrus rootstock improvement has relied historically on clonal selections chosen on the basis of field performance. A few rootstocks have come inadvertently from cold-hardy citrus scion improvement programs, and these have become the most commonly used rootstocks in Florida citriculture. In addition to biological impediments to genetic progress, the lack of understanding of the genetics underlying important characteristics and the subsequent inability to select superior individuals in an efficient, cost-effective manner have limited the impact of applied plant breeding on citrus rootstock improvement. Genetic research on the cellular and molecular levels, using recently developed techniques, has provided new opportunities for progress. The potential of plant transformation, somatic hybridization, and genome mapping to ameliorate the breeder's efforts at citrus rootstock improvement will be discussed.
CALIFORNIA CITRUS ROOTSTOCKS
Authors: Ferguson Louise
Published: April 2024

Though California is currently not facing the intense disease pressure that led to the development of the Troyer and Carrizo citrange rootstocks (sweet orange × trifoliate orange hybrids) that replaced the sweet orange (Citrus sinensis [L.] Osbeck) rootstocks, the California industry is still actively involved in breeding and evaluating rootstocks.

All potential rootstocks are still screened for the common fungal and viral diseases of citrus as well as for nematode susceptibility and nursery characteristics. The candidates that prove resistant are then evaluated as budded trees for scion compatibility, climatic and edaphic adaptability, and horticultural traits. Currently, rootstocks are not evaluated for salinity.

Currently C-32 and C-35, citrange hybrids of `Ruby' orange and trifoliate orange (Citrus sinensis [L.] Osbeck and Poncirus trifoliata [L.] Raf.) are being evaluated with a number of navel and Valencia scions. There is also increasing interest in finding compatible productive rootstocks for new mandarin and grapefruit introductions.
FRUIT ROT CONTROL WITH BIOLOGICALLY DERIVED SUBSTANCES
Authors: Takeda Fumiomi , Janisiewicz Wojciech
Published: April 2024

Postharvest decay represents major losses in the horticultural industry. Synthetic fungicides are an effective tool in controlling postharvest diseases. However, the need for new methods to control postharvest diseases is emphasized because of resistance to certain fungicides, increased incidence of iatrogenic diseases, health risk concerns, and regulatory constraints on pesticide usage.

The use of biologically derived bioactive substances is an alternative approach for the control of postharvest diseases. For example, pyrrolnitrin, a compound produced by Pseudomonas cepacia, has high antifungal activity toward several pathogenic fungi. Chitosan, obtained from deacetylation of chitin, activates the natural defense mechanism in the host tissue. Some volatile compounds from plants and fruits have fungitoxic properties. Hinokitiol, an extract from Japanese cypress trees, is highly effective in extending the shelflife of peaches. The usefulness and limitations of a number of natural bioactive substances will be discussed.
EDIBLE COATINGS FOR FRUITS AND VEGETABLES.
Authors: Nisperos-Carriedo Myrna o. , Baldwin Elizabeth A.
Published: April 2024

Several processes including controlled atmosphere, hypobaric storage and the application of protective films have been developed to extend shelf-life of fruits and vegetables. Recently, the application of edible coatings that can simulate controlled atmosphere storage to prolong product freshness is becoming a popular concept. The ability of these coatings to extend postharvest storage life depends on their differential permeability to CO2, O2 and water vapor.

This talk will describe the developmental aspect and specific applications of edible coatings on various fresh and minimally processed fruits and vegetables.
INTRODUCTION AND RELEASE OF NEW WOODY LANDSCAPE PLANTS FROM THE UNIVERSITY OF MINNESOTA
Authors: Pellett Harold
Published: April 2024

The woody landscape plant breeding project in Minnesota is a very diverse program. It encompasses a broad spectrum of plant genera & utilizes several different approaches to develop new cultivars. The primary applied objective of the project is to develop high quality, woody landscape plants that are well adapted to the environmental conditions of Minnesota and other northern areas. New cultivars are developed through (1) controlled hybridization, (2) by observation and selection of superior plants growing in the wild or in planted landscapes, (3) from plant populations grown from native seed sources and (4) from plants acquired from seed exchanges, etc. with other arboreta.

Two red maple cultivars are patented. The rest of our introductions have been through the royalty program of the Minnesota Nurserymens' Research Corporation. Brief descriptions of plants introduced from our program will be given and the introduction processes will be described.
NEW CHEMICAL TREATMENTS FOR HORTICULTURAL SEEDS
Authors: Rushing Kyle W.
Published: April 2024

The utilization of seed applied pesticides has been lacking in the area of horticulture for many years. Rather than relying on this type of pesticide application, most commercial producers have utilized soil drenches, dips, granular and foliar spray applications to provide the desired control. As a result of the recent Benlate incidents, the chemical industry will continue to be reluctant to register products for seed treatment, granular and foliar applications. The potential liability that exists from these product uses makes it impossible for chemical companies to accept this responsibility. A discussion of those products that are available as seed treatments is restricted to two products, i.e., Thiram 42-S and Vitavax -34. The limitation of the product use patterns and a discussion of potential options will be made. EPA's document on warranties, disclaimers and limitations on pesticide labels will be discussed as it relates to pesticide uses.
BIOLOGICAL ROLES AND BIOCHEMISTRY OF THE LIPOXYGENASE PATHWAY
Authors: Gardner Harold W.
Published: April 2024

Two branches of the lipoxygenase pathway seem to universally predominate in plants. One such pathway involves chain-cleavage of fatty acid hydroperoxides into aldehydes, and another is chain cyclization of a linolenic hydroperoxide with eventual transformation into jasmonates. The aldehyde pathway, which furnishes green-grassy or cucumber-like odors, is triggered by wounding or pathogen attack. The aldehydes generated are defensive against the growth of pathogenic bacteria/fungi. Recently, the aldehyde pathway has been extended to include the transformation of cis-3-hexenal and cis-3-nonenal into 4-hydroxy-2-hexenal and 4-hydroxy-2-nonenal, respectively, the latter of which are cytotoxic. The other pathway leads to the biosynthesis of the jasmonate phytohormones. The initial biosynthetic product, 7-isojasmonic acid, becomes converted into jasmonic acid, as well as a large family of related compounds. The jasmonates control diverse physiological processes, such as induction of proteins, defensive enzymes, tuberization, secondary metabolites, and senescence.
APPLE SCALD: RE-EXAMINATION OF THE PEROXIDATIONS BELIEVED TO BE ITS CAUSE
Authors: Bramlage William J. , Zhanyuan Du
Published: April 2024

Superficial scald of apples is believed to be caused by the oxidation of α-farnesene to conjugated trienes, which then perturb membrane lipids and cause cell death. The antioxidant diphenylamine that is used for commercial scald control is believed to inhibit α-farnesene oxidation. However, measurement of TBA-reactive substrates and total peroxides in apple peel showed that marked increases occurred as fruit senesced, but only slight changes were associated with conditions that specifically led to scald development. Similarly, changes in activity of catalase, peroxidase, and SOD occurred as fruit senescent progressed, but changes in these enzymes had no association with conditions that promoted scald development. We also found that DPA primarily affected accumulation of α-farnesene, with only a small effect on its oxidation to conjugated trienes. These results cast doubt on the hypothesis that lipid peroxidation in membranes produces superficial scald on apples.
TOWARD A COMPREHENSIVE MODEL FOR LIPID PEROXIDATION IN PLANT TISSUE DISORDERS
Authors: Shewfelt Robert L.
Published: April 2024

Lipid peroxidation has been observed in seed aging, hypersensitive reaction, senescence and stress response to high temperatures, chilling, freezing, drought and pollutants. It is not clear whether peroxidation represents a primary cause of any of these events or merely a secondary effect. A body of evidence is accumulating that suggests the source of initiation is not as important as the balance between degradative reactions and endogenous defense mechanisms within the membrane. Furthermore, different membranes within the cell show differences in susceptibility to peroxidative challenge suggesting that localization is critical for a peroxidative link to these disorders. A comprehensive model is presented that accounts for disparate symptomology across a wide range of disorders and horticultural crops with peroxidation as a critical controllable event.
MARKETING OF LIGHTLY PROCESSED FRUITS AND VEGETABLES
Authors: Schlimme Donald
Published: April 2024

The U.S. marketplace has been especially receptive and attuned to growth in per-capita consumption of fresh produce for both at home and away from home use. In the next 30 years, the USDA projects that consumption of fresh produce will increase 72 to 84%. With this in mind, consumers have demanded fresh produce which can be consumed with less preparation time while maintaining high standards of quality. Attention to quality, greater convenience and maximum safety will be called for to continue increased consumption during the economic uncertainties of the 90's and beyond. Marketing, storage, and distribution factors necessary to sustain the growth of lightly processed produce consumption now and in the next 10 years will be discussed.
THE EFFECT OF RHYZOSPHERE PH ON THE ROOT DEVELOPMENT OF CUCUMBER AND CANTALOUPE.
Authors: Abou-hadid A.F. , Saleh M.M , Medany M.A. , EL-Beltaqy A.S.
Published: April 2024

Cucumber (Cucumls sativus L.) and cantaloupe (Cucumis melo var. Cantaloupensis L.) seedlings have been subjected to a wide range of rhyzosphere pH. Each plant was grown in one pot in water culture. The results obtained showed a great influence of pH on plant root length, root diameter and number of roots, in addition to the subsequent effect on the vegetative growth. The experiment suggests the importance of rhyzospher pH to produce healthy cucumber and cantaloupe seedlings with the maximum root performance. Obtained date were discussed according to the prevailed microlimatic conditions.
THE EFFECT OF IRRIGATION AND/OR LEAF REMOVAL ON FRUIT QUALITY OF REDSKIN PEACH DURING FINAL SWELL
Authors: Lasswell James L. , Worthington Josiah W.
Published: April 2024

In August, 1992 a preliminary study was conducted to determine how irrigation (I) and/or termination of photosynthesis (by removal of leaves (L) from branches to simulate full shade) would affect peach quality of Redskin peach during final swell. Four treatments (1. w/o I-w/L; 2. w/o I-w/o L; 3. w/I-w/L; 4. w/I-w/o L) with four replicates (R) per treatment (T) were tested Twenty-one fruit in each T/R were numbered 1 through 21 with a black permanent marker. Fruit size (FS) was measured daily and three fruit were removed from each T/R every two to three days until all fruit were soft ripe, then FS, soluble solids (SS), titratable acidity (TA), ground color (GC), density (D), and firmness (F) were determined for each peach. There were significant treatment differences in FS, D, SS, TA, and SS to TA ratios at some point during the final swell, though SS and D were not different when the fruit became fully ripe. Other parameters measured were not affected by treatments used.
PERFORMANCE OF FOUR PEACH TRAINING SYSTEMS OVER EIGHT YEARS
Authors: Olien William C. , Ridley John D. , Coston D.C. , Hardin M.E
Published: April 2024

The low density, free-standing Open Center (OC) training system for peach production is inexpensive to establish and maintain. However, a lengthy establishment period is required before profitable yields are obtained and uneven distribution of fruiting wood within and between trees reduces potential fruit production and quality. Redhaven/Lovell trees were planted in 1985 to evaluate four peach training systems: OC, Central Leader (CL), Y-Trellis (YT), & Meadow Orchard (MO) planted at 278, 1111, 2222, & 3333 trees/ha, respectively. YT trees were trained with two scaffold limbs oriented across the row, each supported at the top by one wire (8 feet above ground). MO was managed as the Intensive System described by Erez. Irrigation was not available. Crop was reduced by drought in 1988 and by frost in 1990 & 92. YT produced profitable yields in the third season, with good light distribution throughout the canopy. OC trees required seven years to reach yields of YT. Excessive shoot growth following spring frosts has been difficult to manage in CL and MO, resulting in shading out and loss of fruiting zone. Training system has affected fruit number more than fruit size or quality.
EVALUATION OF LOW-TEMPERATURE TOLERANCE OF FLORAL AND VASCULAR TISSUES OF VACCINIUM ANGUSTIFOLIUM.
Authors: Cappiello Paul E. , Dunham Scott
Published: April 2024

Six clones of Vaccinium angustifolium and two clones of V. mvrtilloides were studied during the winters of 1991-92 and 1992-93. Plants were evaluated for low temperature tolerance of vascular and reproductive tissues.

Over the course of the study, there was a significant difference in low temperature tolerance of flower bud tissue with respect to stem position. Terminal buds hardened later and to a lesser degree than did those located lower on the stem. In addition, flower primordia and flowers were evaluated for low temperature tolerance. The initiation of visible bud swelling was not accompanied by a significant decrease in hardiness; however a significant change was evident once the corolla became clearly visible. This report will discuss the significance of these findings as they relate to frost protection.
PLANT GROWTH AND LEACHATE AS AFFECTED BY CONTROLLED-RELEASE AND LIQUID FERTILIZER
Authors: Schuch Ursula K. , Yates Marylynn V.
Published: April 2024

Poinsettia (Euphorbia pulcherrima `Gutbier V-14 Glory') were grown using commercially available poinsettia fertilizer of various combinations of controlled-release (CRF) and constant liquid fertilizer (LF). At the end of the production period, plants treated with 83, 165 or 250 mg/l LF only were 10% taller than plants treated with the same concentrations of CRF. The total number of cyathia and the number of open cyathia at harvest was 18% and 50% higher for plants treated with LF only compared to plants treated with CRF only. Plants treated with 165 CRF/ 83 LF or 83 CRF/250 LF were not different compared to 250 CRF/0 LF or 0 CRF/ 250 LF in height, number of cyathia at anthesis, and total number of cyathia at the end of the production period. When LF was changed to clear water 5 weeks before the end of production, nitrate runoff from 83 CRF/250 LF treatment was reduced 30% for the last two weeks, and from the 165 CRF/83 LF treatment nitrate leachate was reduced gradually from 33 to 66% over the 5-week period.
MORPHOLOGICAL AND ENZYME CHARACTERIZATION OF AN IMPATIENS GERMPLASM COLLECTION.
Authors: Lerch V. D. , Ng T. J
Published: April 2024

An Impatiens germplasm collection consisting of accessions (from Africa, New Guinea [NG[, Sri Lanka, and Java/Celebes, a NG breeding population, and selected interspecific hybrids was characterized for 32 morphological traits and two ensyme systems, peroxidase (PER) and aspartate amino transferase (AAT). Thirteen PER and three AAT isozymes were identified, and both enzyme systems appeared to be co-dominatly inherited. There were unique zymograms for the accessions and the interspecific hybrids, but not the NG breeding population.

A Generalized Fisher Exact Test indicated that qualitative characters of the accessions were independent of each other, of isozyme traits and of geographical origin of the accession; this was not true for isozymes. Principal component analysis combining both morphological and isozyme traits uniquely separated the accessions while also indicating clusters of similarity. Extensive genetic diversity was indicated for all traits in the accessions and for quantitative traits in the NG breeding population.
PILOT PROJECT TO CRYOPRESERVE DORMANT APPLE(Malus sp.) BUDS
Authors: ForslineL Philip L. , Stushnoff Cecil , Towill Leigh E. , Waddell John , Lamboy Warren F.
Published: April 2024

Dormant buds of 64 apple accessions from the National Germplasm Repository (NGR), Geneva, NY were cryopreserved at the National Seed Storage Laboratory (NSSL), Fort Collins, Co. Initial tests after 1 mon, 1, 2, and 3 years of LN2 storage showed no decline in viability. Storage of 16 cultivars (1988/89 and 1989/90 dormant seasons) with a broad range of cold-hardiness characteristics has shown approx 45% viability by patch budding. Storage from dormant seasons of 1990/91 and 1991/92 included 48 cultivars selected for excellent cold-hardiness characteristics. With approx 85% initial viability of these cultivars, a more sensitive statistical analysis can be performed over years. Overall viability over storage duration and sampling years showed 32 had more than 80%, 55 had more than 50% and only 4 had less than 30%.
DEVELOPMENT OF A SEED BIOASSAY FOR THE STUDY OF THE ALLELOPATHIC POTENTIAL OF LYCOPERSICON HIRSUTUM.
Authors: Bish Eric B. , Bewick Thomas A. , Shilling Donn G.
Published: April 2024

A seed bioassay was developed in order to elucidate the mechanism of interference in Lycopersicon hirsutum. Extracts of L. hirsutum were compared to extracts of other plant species, several of which have been determined to demonstrate allelopathic properties. Measurements of germination, root growth, and hypocotyl elongation were used as parameters for these experiments. A titration experiment was conducted to determine the concentrations needed for seed inhibition. I50 values were generated to determine the concentration needed to inhibit 50 percent of the seeds for each species. L. hirsutum possessed a significantly greater inhibition than any of the other species examined. Lettuce (Lactuca sativa) and common purslane (Portulaca oleracea) seeds provided the best response because of quick uniform germination.
SWEETPOTATO LATEX: EFFECT ON SWEETPOTATO WEEVIL FEEDING AND OVIPOSITION
Authors: Kays Stanley J. , Data Emma S.
Published: April 2024

Latex is known to act as a natural defense system in some laticiferous plants against certain herbivores. The importance of latex produced by the sweetpotato, Ipomoea batatas, Lam., as a defense mechanism against the sweetpotato weevil, Cylas formicarius elegantulus (Summers) (Coleoptera: Curculionidae), was tested. Distinct genetic and environmental differences were found in latex production in a broad cross-section of sweetpotato germplasm (96 lines). Most lines produced 2.6 to 10 mg fwt-vine-1 of latex when the second internode from the apex was severed. Some lines, however, produced substantially more, the highest being 48.3 mg·vine-1. The percent dwt of the latex exudate ranged from 2.5 to 54, with most lines falling within the 10 to 22.5% range. The amount of latex (fwt) released varied (1.9X) with differing environmental conditions (primarily light intensity). Young vine material produced more latex and had less feeding by the weevil than in older more mature portions of the vine. Application of latex to the surface of root cores markedly reduced feeding (67%) and oviposition (92%) after 24 hours in choice and oviposition in no choice experiments. Addition of latex to a semi-artificial media also significantly reduced feeding. Leaf feeding location (veins) and direction (basipetal), however, were not indicative of a deterrent role for latex. Collectively, existing evidence does not support a significant deterrent role for latex with regard to the sweetpotato weevil, however, additional information is needed on latex chemistry and quantitative and qualitative variation in latex within the sweetpotato genepool.
DRIP IRRIGATION RATES AFFECT WATERMELON YIELD
Authors: Maynard Donald N. , Clark Gary A.
Published: April 2024

`Crimson Sweet', `Jack of Hearts', `Mickylee', `Royal Jubliee', and `Sangria' watermelon transplants were set in raised, fumigated, 61-cm wide polyethylene-mulched beds with previously installed drip irrigation tubing (Roberts Ro-Drip) with 30-cm emitter spacing and 6.25 liter·min-1·100 m-1 nominal discharge in the spring 1992 season. After a 14-day crop establishment period, variable irrigation rates based on ratios of calculated Penman reference ET0 were used. For the remainder of the season, 96, 185, or 300 mm of irrigation were applied. Highest yields and average fruit weight were produced by `Royal Jubilee'. Highest soluble solids and frequency and severity of hollowheart were produced by `Jack of Hearts'. Except for `Royal Jubilee', there was a quadratic yield response to irrigation rate for the other varieties.
MINI WATERMELON MARKETING AND DRIP IRRIGATION STUDY
Authors: Sanders D. C. , Bailey K. A. , Adams D. E. , Schultheis J. R. , Estes E. A.
Published: April 2024

`Tiger Baby' mini watermelons were direct seeded into black plastic mulch with drip fertigation irrigation. Drip lines were run for 300 m feet, in excess of that recommended. Single plants were 45 cm apart in 1.5 m rows. Yields were taken from the total 300 m and from the first 90 m of row. Yields only slightly affected by drip tubing type. We also conducted a marketing test with these watermelons. Boxes of 9 melons each (2.5-3.6 kg) were sold at `upscale' grocery chain. Produce managers and customers were surveyed. Size seemed to be the most important selling point, followed by taste. Sales increased once the manager cut a sample melon. In general 40% of the melons sold in the first week and the remaining 60% the second week. Prices averaged $2.00 and minimelons competed favorably with standard sizes.
THE WOODLAND VEGETATION OF STEPHEN F. AUSTIN STATE UNIVERSITY REVISITED: A CAD\GIS ANALYSIS
Authors: Creech D. , Singhurst J. , Kulhavy D. , Seibel G. , McDonald D.
Published: April 2024

Urban landscape ecology is a new interest that crosses several disciplines: botany, forestry, horticulture, sociology and land use planning. University forest environs are often the most degraded; foot traffic, development and a shortage of funds for significant tree plantings are main culprits. SFASU lies in the pineywoods region of east Texas and is known as the “university among the pines.” The campus is blessed with many patriarch pines and hardwoods. Computer-assisted drafting (CAP) and Geographic Information Systems(GIS) platforms are being utilized to map the campus vegetation. A 1992 vegetative analysis, when compared to similar studies in 1971 and 1983, indicates a loss in species diversity and frequency with little change in basal area. AutoCad*, LandCadd*, and Studio-3D* are being integrated into a multi-disciplinary project to develop a three-dimensional biotic/abiotic model of the campus. That model will be used as a “fly-through” visualization tool to develop forest conservation strategies most likely to succeed in a sustainable fashion.
A GRAPHICAL INTERFACE FOR MAINTAINING PLANT ACCESSION AND DATA RECORDS IN dBASE IV
Authors: Needham Douglas C
Published: April 2024

The Oklahoma Botanical Garden and Arboretum (OBGA) at Oklahoma State University was awarded an “America the Beautiful” grant from the Oklahoma Department of Agriculture and the Oklahoma Urban and Community Forestry Council to develop a plant database and plant identification labels.

The OBGA Plant Information Manager version 1.0 was created to assist students, volunteers, and staff of public gardens with maintenance of data from plant accession, growth, flowering, fruiting, etc. The program is a graphical interface to dBASE IV records, created with Borland's ObjectVision 2.0 for Windows.

Users are prompted for information via “check boxes” ⊗, “radio buttons” ⊙, and selection lists, thereby reducing incorrect entries. The series of forms leads the user through the process of plant accessioning, including information on donor, size, flowering season, fall foliage color, planting site, cultural preferences, etc.
MULTIYEAR PRODUCTION CYCLES OF VALENCIA ORANGE SOLUBLE SOLIDS PER FRESH WEIGHT COINCIDE WITH EL NINO EVENTS
Authors: Albrigo L. Gene
Published: April 2024

Using fruit yield, fruit quality and weather data summaries from Florida during the previous 25 years, this study sought correlations between climatic conditions, annual `Valencia' orange yields and fruit quality. Soluble solids, expressed as g per kg of harvested fruit, fluctuated from 44 to 81 g per kg fresh fruit in rhythmic cycles of 3 to 5 years duration. These cycles did not relate to cycles of fruit production per tree nor to changes in average fruit size from season to season. The years with high solids appear to coincide with the warm winters of El Nino cycles and years with low solids coincide with wet winters events. Annual temperature and rainfall patterns along with possible physiological responses related to trends in production of soluble solids will be discussed.
THINNING `DELICIOUS' APPLE: TRIALS AND TRIBULATIONS
Authors: Neilsen John C. , Dennis Frank G.
Published: April 2024

Response of `Delicious' apple to chemical thinning is often erratic. Experiments were conducted to test the effects of crop density, thinning and strain on yield and fruit size. The relationship between crop density and fruit size was determined in 3 orchards over 2 years. In one orchard the relationship was consistent in both years, but in the other two, it varied widely. Naphthaleneacetic acid (NAA) was applied to 10-year-old trees at one location in 2 successive years (1989-90). NAA treatments were compared with early hand thinning (15 days post bloom) in 1989 and with NAA plus carbarl (Sevin) in 1990. In 1989 both NAA and hand thinning reduced crop density and yield, but only hand thinning increased fruit size. No treatments applied in 1990 reduced crop density, and effects upon size and economic return were minimal. Strain differences in response to NAA and its amide (NAAm) were evaluated in 1989 and 1990. NAA (13 and 20 ppm) failed to reduce crop density in 1989, but fruit size was reduced. NAAm at 50 ppm overthinned both years, but was effective at 25 ppm in 1990. Fruit set was generally lower in non-spur than in spur strains.
COMPARISON OF NAA AND SEVIN PETAL FALL SPRAYS ON FRUIT SET OF APPLES
Authors: Williams Max W.
Published: April 2024

In Washington and other western states Elgetol, a blossom thinning agent was previously used before the postbloom NAA and Sevin applications and there was no need for an earlier timing of NAA and Sevin treatments. In 1989, Elgetol was removed from the market by the manufacturer because of minor crop use and the high cost of re-registration. Without a blossom thinner it is impossible to guarantee a return bloom on severe biennial bearing cultivars such as Golden Delicious and Fuji. Even though adequate fruit thinning occurs with the postbloom thinning sprays, flower Initiation may not occur for the next years crop because the application is made too late.

NAA and Sevin are used as postbloom sprays for reducing fruit set of apples. The usual time of application is when the largest fruit are from 10 to 15 mm in diameter. Sprays applied at the 10-15 mm fruit diameter stage take advantage of warm weather after spraying which increases stress and maximizes reduction of fruit set with a minimum effect on the seed number, however, when temperature is cold seed abortion occurs without adequate reduction of fruit set.

This report compares the efficacy of the postbloom thinners NAA and Sevin as early petal fall sprays for reducing fruit number and increasing return bloom the following year. Sevin is most effective as an apple fruit abscission agent when applied at petal fall. In trials for 2 years there was no reduction in fruit seed number, no reduction in fruit size and no effect on fruit shape. In comparison NAA applied at petal fall tended to reduce seed number, reduce fruit size, flatten or distort fruit shape and cause leaf curling.
EFFECTS OF GIBBERELLIN AND GIRDLING ON THE YIELD OF “NOVA” (CLEMANTINE × ORLANDO TANGELO) AND “NIVA” (VALENCIA × WILKING)
Authors: Goren R. , Huberman M.
Published: April 2024

GA3 and/or girdling half of the main branches significantly increased both fruit set and yield, but caused the highest rate of fruitlet drop. Spraying GA3 at mid-anthesis is the best treatment to improve fruit set and yield. Yield loss of up to 48% was due to rind-splitting-induced fruit abscission in August and mid-October. Morphological study of splitting revealed that this phenomenon occurred at the stylar end starting at the flavedo, progressing into the albedo and leaving the vascular bundles intact, although they separated later. Spraying Nova trees with different growth regulators in July, failed to reduce splitting. Reducing water supply by 35 or 50% from August onward, reduced rind splitting by up to 35% accompanied by a decrease in fruit size and yields. Internal quality was not affected when water supply was reduced by 35%. Reducing water supply by up to 50% decreased TSS/acid ratio and percent of juice. It is therefore, questionable whether reduced water supply is an effective treatment for limiting rind splitting and premature fruit drop.
RHIZOBIUM GROWTH AND SURVIVAL AS INFLUENCED BY TEMPERATURE
Authors: Baptiste Raymond , Marsh Lurline , Marsh Dyremple , Trinkiein David
Published: April 2024

The number of viable cells produced by Rhizobium on solid media gives an indication of the strains survivability when used as an inoculant. This study was conducted to determine the viability of different strains of Bradyrhizobium. and their ability to nodulate pigeonpea (Calanus calan) and cowpea (Vlgna unguiculata) genotypes at two temperature regimes: 20/10°C and 30/20°C (day/night). Bradyrhizobium strains USDA 3278, 3362 and 3458 were cultured in yeast mannitol broth for 7 days from which a 10% dilution was made. From this dilution, 0.1 ml of a further 10 dilution was allowed to grow on yeast mannitol agar plates at the test temperatures. Strains cultured at 30/20°C had a higher number of viable cells than those cultured at 20/10°C for 4 days. While there was no difference between Rhizobium strains 3278 and 3362, strain 3458 had the highest number of cells per ml of 7-day old broth culture. Pigeonpea and cowpea plants inoculated at 20/10°C with the three Rhizobium strains and those inoculated with 3362 at 30/20°C had no nodules at 30 days after planting. At 30/20°C, plgeonpea and cowpea plants Inoculated with strain 3458 produced a higher number of nodules than those inoculated with strain 3278. These results indicate that temperature Influences the Rhizobium strains and their ability to nodulate plgeonpea and cowpea.
MAIN VERSUS EXTERNAL ROOTS AND PHOSPHORUS EFFICIENCY IN COMMON BEAN: ARE ALL ROOTS CREATED EQUAL?
Authors: Snapp Sieglinde S. , Lynch Jonathan
Published: April 2024

Separate evaluation of main and external roots was critical to understanding results from a study on phosphorus (P) efficiency in common bean. A subsection of the root system, including both main roots and external roots, was compartmentalized and subjected to low P conditions. The rest of the root system was maintained at either low or high P-nutritional status. P distribution at the mid-pod fill stage was determined for root components (main and external roots) and shoot components (leaves, stems, pods). A 50% inhibition in main root growth and moderate reductions in diameters of both root types were found in low P plants compared to high P plants. Marked reduction in main root growth, coupled with a limited reduction in external root growth and thinner roots, allowed low P plants to reduce biomass and P investment in compartments by 54 and 42%. Yet root exploration of the compartment, in terms of root length per soil volume, was similar for both low and high P plants. Further, P removal from compartments was similar for roots of low P plants and high P plants. Taken together, the data suggest efficiency of P acquisition in P-stressed common bean is enhanced by selective inhibition of main root growth and continued growth of external roots.
VARIABLE CROP FACTORS FOR COMPUTING CABBAGE WATER USE
Authors: Simonne E.H. , Smittle D.A. , Dickens W.L. , Stansell J.R.
Published: April 2024

`Rio Verde' cabbages (Brassica oleracea L.) were grown in drainage lysimeters on two soil types (Tifton loamy sand and Bonifay sand) in the spring and the fall of 1982, 1983, and 1985. Irrigation regimes consisted of applying water amounts equal to soil water deficit when the soil water tension at a 10-cm depth exceeded 25, 50, or 75 kPa throughout growth of the crops. Because the lysimeters were equipped with rainfall-activated shelters, water applications and evapotranspiration (ETc) were similar. Crop factors (CF) as functions of plant age (i) were computed for all combinations soil type-season-irrigation regime as the ratio between water applications and class A pan evaporation (Ep). No significant differences were observed among soil type or season, but irrigation regimes significantly affected ETc and CF(i). The highest ETc and leaf yields corresponded to the 25-kPa regime. CF(i)=0.025i - 0.0002li2, 0.023i - 0.00017i2, and 0.022i - 0.00017i2, for the 25-kPa, 50-kPa, and 75-kPa treatments, respectively (R2=0.97). Therefore, daily ETc by cabbages can be computed with Ep as ETc = CF(i) × Ep for scheduling irrigation.
MEIOTIC MECHANISMS FOR 2N GAMETE FORMATION IN WILD BLUEBERRY SPECIES
Authors: Filler Debby M. , Vorsa Nicholi
Published: April 2024

In blueberries (Vaccinium spp), 2n pollen production has been identified in both diploid and tetraploid populations. High 2n pollen producers from diploid V. elliotti, diploid V. darrowi, and tetraploid V. pallidum were chosen for meiotic studies. Cytological examination revealed spindle abnormalities, including parallel spindles and tripolar spindles, as well as synaptic irregularities. These aberrations would result in gametes having the genetic equivalent of first division restitution near the centromere and in portions of the chromosome that are not recombinant. Such gametes would be expected to transmit a high level of heterozygosity to resulting progeny. Reciprocal diploid by tetraploid cultivar crosses were made to evaluate the viability of the 2n gametes in the diploids, and to assess the usefulness of the diploids as parents in a breeding program.
GENETIC LINKAGE MAP FOR BLUEBERRY (VACCINIUM spp.) USING RAPD MARKERS
Authors: Levi Amnon , Rowland Lisa J.
Published: April 2024

A genetic linkage map for blueberry has been constructed from over 60 RAPD (random amplified polymorphic DNA) markers that segregated 1:1 in a testcross population of about 40 plants. Prior to map construction, polymerase chain reaction conditions were optimized and RAPD marker reliability was confirmed. The mapping population was derived from a cross between diploid blueberry plants: Fl interspecific hybrid, `US388' (V. darrowi, `Fla4B' × V. elliottii, `Knight'), and another V. darrowi, `US799'. The map currently comprises 12 linkage groups corresponding to the basic blueberry chromosome number and covers a total genetic distance of over 800 cM, with a range of 2-30 cM between adjacent markers. Interestingly, a few pairs of marker loci behaved differently from both linked and unlinked loci, being found at a much higher frequency in the recombinant configuration than the parental configuration possibly suggesting selection for certain combinations of alleles.
MODELLING WATER USE OF GRAPEVINE
Authors: Williams Larry E.
Published: April 2024

An ongoing study measuring grapevine (Vitis vinifera L., cv. Thompson Seedless) water use with a weighing lysimeter is being used to develop a model to simulate vine water use on both a diurnal and seasonal basis. A method to calculate the aerodynamic resistance (ra) of the vines was first determined. Subsequently, a model to predict canopy resistance (rc based solely upon intercepted photon flux density (PFD) was developed. The modeled values of ra and rcwere substituted into a resistance-energy balance equation to predict vine ET. The modeled parameters were validated against diurnal measurements of ET from the lysimeter. The greatest difference between modeled and measured rc occurred prior to 1000 h and subsequent to 1500 h each day. The model overestimated vine ET by 14 and 23% on 16 and 24 June, 1992, respectively. Ambient temperature and vapor pressure deficit were greater on 24 June than on 16 June. Refinements in calculating PFD interception by the vine's canopy early and late in the day and incorporating the effects of other environmental factors on grape stomatal conductance should improve the predictive capabilities of the model.
A NEW SOURCE OF RESISTANCE TO ANTHRACNOSE (RACE 2) IN WATERMELON
Authors: Norton J.D. , Boyhan G.E. , Abrahams B.R. , Huang H.W.
Published: April 2024

In a screening test of 76 PIs, commercial Chinese watermelons, and `Crimson Sweet', PI512385 had the highest disease resistance with a mean rating of 4.5 on a 1-9 scale with 1 = resistant and 9 = susceptible. A second test with PI512385 included material with previously reported resistance (PIs 270550, 326515, 271775, 271779, 203551, 299379 and 189225) and `Crimson Sweet', a susceptible check showed PI512385 had significantly more resistance than `Crimson Sweet' but was not significantly more resistant than the PIs. PI512385 had a mean rating of 2.2 in the second test.