bluuebunny/crossref_metadata_2025 huggingface dataset:
Allozyme and RAPD Analysis of the Geographic Variation and Genetic Diversity in Natural Populations of the American Chestnut
Authors: Huang Hongwen , Dane Fenny , Kubisiak Tom
Published: February 2019

The population structure and genetic diversity of American chestnut trees collected in nine states along the natural range of the species was evaluated using 20 isozyme loci. Genetic heterozygosity (Ht:Nei, 1978) ranged from 0.089 in the Georgia and 0.094 in the North Carolina population to 0.172 in the northernmost (Connecticut) and 0.181 in the southernmost (Alabama) population. Four populations (Pennsylvania, New York, Virginia, and Alabama) were selected for RAPD analysis using 22 loci randomly distributed across the chestnut genome. The highest level of heterozygosity was in the Alabama population. UPGMA phenograms generated for the isozyme and RAPD markers using Nei's genetic identity showed similar genetic relationships among American chestnut populations.
Potassium Fertilizer Effects of Potato Yield and Petiole Sap Potassium Concentrations
Authors: Rosen Carl , Wang Wenshan , Birong David
Published: February 2019

A 2-year field study was conducted on a low- to medium-K testing sandy soil 1) to evaluate the effects of various K management strategies on potato (cv. Russet Burbank) yield and quality and 2) to calibrate a petiole sap test for determining plant K status. Treatments included banded applications of potassium chloride fertilizer at planting with K ranging from 0 to 300 kg·ha–1 in 75 kg·ha–1 increments. Comparisons of preplant broadcast + banded applications and evaluation of in-season applications of potassium nitrate also were made. In both years, tuber yield increased with increasing banded K fertilizer up to 150 kg ha-1 K the first year and 225 kg ha-1 K the second year. In-season applications of potassium nitrate increased tissue K levels, but at equivalent K application rates, timing of K application had no effect on yield. Petiole K concentrations, measured on a dry weight and sap basis, increased with increasing K fertilizer application. Potassium concentrations in nondiluted sap determined with the Cardy K electrode were ≈200 to 2500 ppm lower than those determined by flame emission. The greatest discrepancy occurred at the higher K sap concentrations. Potassium concentrations determined with the Cardy electrode in sap diluted with aluminum sulfate or deionized water were much closer to those determined by flame emission. These results suggest that dilution of the sap is necessary to obtain accurate K concentrations in petiole sap.
Potassium Rates Affect Yield of Two Muskmelon Varieties in Florida
Authors: Pacheco Alvaro O. , Hochmuth G.J. , Maynard D.N. , Csizinszky A.A. , Sargent S.A.
Published: February 2019

Optimum economic yield is produced when nutrients in the proper amounts are supplied to the crop. Crop nutrient requirements (CNR) of essential elements have been determined for the major vegetables produced in Florida. However, for minor crops, such as muskmelon, little research has been conducted to determine the CNR, especially potassium. In many vegetables, yield has responded to increasing K rates when other elements were not limiting. Our objective was to determine the K fertility requirement for optimum yield of muskmelon and to evaluate the Mehlich-1 soil test calibration for soil testing low in K (<20 mg·kg–1). Experiments were conducted in the spring and fall seasons of 1995. Potassium at five rates (0, 56, 112, 168, and 224 kg·ha–1) was injected weekly, approximating the growth curve of `Galia' and `Mission'. There were significant yield responses to K fertilization for both cultivars during both seasons. During spring, average marketable yield was 14.5, 26.1, 31.9, 31.5, and 36.3 Mg·ha–1 and for fall, average marketable yield was 15.8, 32.9, 37.8, 37.2, and 36.4 Mg·ha–1 for the previously described K treatments, respectively. The cultivar response for both seasons was described by a linear-plateau model. In spring, yield was maximized with K at 116.8 and 76.3 kg·ha–1 for `Galia' and `Mission', respectively. In fall, K at 73.3 and 68.3 kg·ha–1 produced the peak response for the same cultivars. These results indicate that maximum yield of muskmelon in Florida can be obtained at considerably less K than the current recommendation of 140 kg·ha–1.
Potassium Requirements for Optimal Processing Tomato Yield and Fruit Quality
Authors: Hartz T.K. , Mullen R. , Cahn M. , Miyao G.
Published: February 2019

Trials were conducted in nine commercial processing tomato fields in California from 1994 to 1995 to assess the effects of potassium fertilization on fruit yield and quality. Sites were selected to represent a range of ammonium acetate extractable soil K levels (91 to 284 mg·kg–1, top 30 cm) and K release rates (K at 1.8 to 8.5 mg·kg–1·d–1). Potassium was applied in furrow or drip irrigation during the fruit bulking stage at seasonal rates from 90 to 135 kg·ha–1. Significant yield increase (4% to 24%) was observed at three of the four sites with extractable soil K <125 mg·kg–1 (K released at <3.1 mg·kg–1·d–1); no yield response was observed at the five sites with greater soil K supply. Fruit color and soluble solids content was unaffected by K fertilization at any site. Additionally, red fruit of two cultivars (`Halley' and `Heinz 8892') were collected from 80 commercial fields in 1995 and evaluated for soluble solids content, color (of a comminuted sample as well as visual ranking of internal and external ripening disorders), and tissue K concentration. Fruit K concentration was poorly correlated with any quality characteristic. We conclude that yield response to K fertilization can be adequately predicted by either soil test method and that K supply plays a relatively minor role in tomato fruit quality under representative field conditions.
Horticultural Science and Rare Plant Conservation
Authors: Affolter James M.
Published: February 2019

Horticultural science has an essential role to play in the conservation of rare plants, but to date, most horticultural research in this field has taken place on an informal rather than experimental basis. Plant conservation as a scientific and practical discipline would benefit greatly from applying the more rigorous approach characteristic of commodity-oriented horticultural research. In turn, the profession of horticultural science has a great deal to gain by participating more actively in plant conservation programs. Benefits include an influx of new ideas, new people, and new resources. Some of the traditional research fields within horticulture that are directly relevant to rare plant conservation include: seed technology, propagation and tissue culture, nutrition, growth regulation, soil management, and protection from pests and diseases. Three case studies illustrate various ways in which the theory, technology, and knowledge base of horticulture can be applied to plant conservation. They include the rare plant propagation program at Bok Tower Gardens, Lake Wales, Fla.; mountain meadow revegetation projects in Mount Rainier and Olympic National Parks in Washington; and research activities of the recently established Georgia Plant Conservation Alliance.
Master Gardener—Tree Stewards: Advanced Training to Enhance Community Volunteerism
Authors: Day Susan D. , Dorn Sheri T. , Relf Diane , Harris J. Roger
Published: February 2019

Virginia Cooperative Extension's (VCE) Master Gardener!Tree Steward program (MGTS) provides advanced training in leadership development and arboriculture to Master Gardener (MG) volunteer educators so that they may expand the influence of extension through leadership in community forestry. According to a statewide survey, 70% of VCE MGs and agents with MG programs would like to be involved in community tree programming. Only 26% were currently involved. Typically, agents cite limited staff and volunteer resources as the primary factors in restricting program expansion. Furthermore, 90% of municipal foresters indicated they would like to work with trained volunteers. The MGTS program simultaneously answers the desire of MGs to expand their role in the community landscape and the need of VCE to expand its outreach with increasingly limited resources. MGTS training, guided by a 10-unit resource book, integrates technical and program management expertise to foster volunteer pride and self-sufficiency. This allows MGTSs to coordinate much of their own training and recruit and manage large numbers of non-MG volunteers to whom they can provide limited training for specific projects, thus, allowing program expansion without additional staff.
Evaluation of Flavor and Potential Anticancer Properties of Fall Onions
Authors: Patil Bhimanagouda S. , Dean Bill B.
Published: February 2019

Fall onions, grown for their long shelf life, have become popular both in domestic and export market. Sixty cultivars of onion from 14 major seed companies were grown in Quincy, Wash., and were analyzed for their flavor, quality, and anticarcinogenic flavonol, quercetin. The highest quercetin concentration (in mg·kg–1 fresh weight) was observed in the red onion `Feugo' (495.6) followed by `Tango' (396.8), while the least amount was in the yellow onion `Pinnacle'(152.5). The pyruvic acid content varied from 1.5 to 18.7 mmol·g–1 and total sugar (glucose, fructose, and sucrose) levels ranged from 9.4 to 36.9 mg·g–1 fresh weight among different cultivars. The ratio of sugar:pyruvic acid showed marked variation (1.6 to 64.00) among different cultivars. The variation in oligosacharides were ≈60-fold over all cultivars. The maximum degree of polymerization (DP) observed was DP8. We conclude that there is a potential for developing a mild onion for longer shelf life and better health properties. Yield at harvest and storage performance based on rot also was evaluated during storage.
Changes in Antiplatelet Activity, Pungency, and Percent Solids of Four Diverse Onion (Allium cepa) Lines During Cold Storage
Authors: Debaene Jan E.P. , Goldman I.L.
Published: February 2019

Raw onion extract contains organosulfur compounds that prevent aggregation of platelets in human blood plasma and influence onion pungency. An increase in antiplatelet activity has the potential of reducing cardiovascular diseases. Accumulating organosulfur compounds directly influences pyruvic acid concentrations and may determine antiplatelet activity. Organosulfur compounds are volatile and may change concentration during storage. A study was conducted to evaluate antiplatelet activity, pyruvic acid content, and percent solids during cold storage. Two low-pungency lines (8155B and Exhibition) and two high-pungency (W420B and W434B) lines were grown in replicated plots at two Wisconsin locations in 1994 and 1995. Bulbs were evaluated for antiplatelet activity, percent solids, and pyruvic acid content at 40-day intervals after onion harvest. We found significant differences for antiplatelet activity and pyruvic acid content among dates of sampling and lines. Averaged over lines antiplatelet activity increased by 73% and 29% over 160 days in storage during the 1994–95 and 1995–96 storage seasons, respectively. Mean pyruvic acid concentrations increased 27% for the 1994–95 storage season and decreased 27.5% for the 1995–96 storage season. There were no significant changes for solids during storage for both years. These data indicate that antiplatelet activity increases during storage, which may be beneficial for human health. Since onions are often stored for long periods of time before sale, an increase in antiplatelet activity may be an added benefit for this crop.
Effect of Storage Temperature on Survival and Regrowth of Vegetatively Propagated Plug-grown Seedlings
Authors: Wang Shi-Ying , Carlson William H. , Heins Royal D.
Published: February 2019

The effect of 6 weeks of storage at 2.5, 5.0, 7.5, 10.0, or 12.5°C in a glass greenhouse was determined on 11 vegetatively propagated annual species. Fresh weight (total, shoot, and root) and height of 30 plants per species in each storage temperature were measured at the end of storage. Another 30 plants were transplanted into 15-cm pots (three plants per pot) and grown under natural light in a 20°C glass greenhouse for 3 weeks. Three species showed chilling injury or died during storage at ≤7.5°C. Plant height and shoot fresh weight at the end of storage for most species increased linearly as storage temperature increased. Storage temperature did not affect the net increase in height or weight significantly during recovery growth, except for plants that exhibited chilling injury at the end of storage.
The ABA Binding Proteins and Their Properties in Grapevine Fruit
Authors: Zhang Da-Peng , Zhang Zi-Lian , Chen Jia , Lu Jiang
Published: February 2019

The abscisic acid (ABA) has a key role in the regulation of grapevine fruit ripening, but the cellular and molecular biological mechanism of the hormone action in the fruit ripening remains unknown. By means of differential centrifugation, microsomes were prepared from Kyoho grapevine (Vitis vinifera L. × V. Labrusca L.) berries, and using the microsomes, we have obtained evidence for the occurrence of specific ABA-binding sites on the membranes with the microvolume radio-ligand binding assay. The binding sites had saturability, high affinity, and low capacity. The results of trypsin and dithiothreitol treatments to the microsomes suggested that ABA binding sites had the properties of proteins that might have disulfide group located at or near the binding site. The binding maximum amount of ABA in the microsomes was at pH 6.0 and the activity of ABA binding proteins was higher at 25 than at 0°C (temperature). The amount of ABA bound reached 54% of the ABA binding maximum (Bmax) for 10 minutes of incubation and Bmax reached for 30 minutes. The dissociation constant (Ka) and Bmax of ABA binding proteins in the microsomes were 17.5 nmol/L and 98.4 fmol/mg protein, respectively.
Qualities of Hot-water-treated Tomatoes
Authors: Hakim Abdul , Kaukovirta Errki , Pehu Eija , Voipio Irma
Published: February 2019

Hot water treatment at 38, 42, 46, 50, and 54 °C for 30 60 and 90 minutes were applied to mature green tomatoes before storing at 2°C for 2, 4 and 6 weeks. Control fruit were treated at 20°C water. After storage all fruit were held at 20°C for 7 days. Control fruit showed lower weight loss, lycopene content, pH, and TSS but higher decay, chlorophyll content, TA, and more Firmness than hot-water-treated fruit. Weight loss, lycopene content, pH, and TSS were progressively increased with increased water temperature from 38 to 54°C, while chlorophyll content, TA and fruit firmness were declined. Among hot-water-treated fruit, least decay were detected in fruit treated at 46°C water 6 weeks stored fruit showed higher weight loss, more decay, lower chlorophyll and lycopene content, TSS, TA, less firmer and higher pH than those fruit stored for 2 or 4 weeks. Increased immersion time from 30 to 90 minutes resulted higher weight loss, lower decay, chlorophyll content, TA, and less firm, but higher lycopene content, TSS, and pH.
Early Changes in Wound-induced and Ethylene-induced Phenylpropanoid Metabolism in Lettuce
Authors: Tomás-Barberdán F.A. , Loaiza-Velarde J. , Saltveit M.E.
Published: February 2019

Mechanical wounding and exposure to ethylene induces an increase in phenylpropanoid metabolism in lettuce and an increase in the concentration of several soluble phenolic compounds that are easily oxidized to brown substances by polyphenol oxidase. To study the early response of lettuce to wounding and ethylene, leaves of iceberg, butter leaf, and Romaine lettuces were either wounded or exposed to ethylene at 10 μL·L–1 in flows of humidified air at 5 or 10°C. Soluble phenolic compounds were extracted at intervals up to 72 hours and were analyzed by HPLC. After 72 hours, wounded leaves of all three lettuce types showed elevated levels of caffeoyl tartaric acid, Chlorogenic acid, dicaffeoyl tartanc acid, and 3,5-dicaffcoyl quinic acid at both temperatures. In contrast, there were no significant increases in soluble phenolic compounds in iceberg lettuce exposed to ethylene at 10°C. At 5°C for iceberg, and at both temperatures for the other two types, there was the same pattern for ethylene treated and wounded leaf tissue. The kinetics of wound and ethylene-induced phenolic metabolism are different and will be discussed in relation to phenolics produced and browning susceptibility.
Evaluation of Heat and Flood Tolerance among Diverse Taxa of Hollies (Ilex)
Authors: Ranney Thomas G. , Ruter John M. , Ruth Clifford D.
Published: February 2019

Temperature sensitivity of net photosynthesis (PSN), dark respiration, and chlorophyll fluorescence was evaluated among three taxa of hollies including I. aquifolium, I. cornuta, and I. rugosa. Variations in foliar heat tolerance among these species were expressed as differential temperature responses for PSN. Temperature optima for PSN was 22.0, 26.3 and 27.9 umol·m–2·s–1 for I. rugosa, I. cornuta, and I. aquifolium, respectively. Differences in temperature optima for PSN and thermotolerance of PSN appeared to result from a combination of stomatal and nonstomatal limitations. At 40°C, potential photosynthetic capacity, measured under saturating CO2, was 4.1, 9.4, and 14.8 μmol·m–2·s–1 for I. rugosa, I. aquifolium, and I. cornuta, respectively. Based on these results, I. rugosa was identified as the most heat-sensitive species followed by I. aquifolium then I. cornuta. Comparative tolerance to root-zone inundation was evaluated among 14 holly taxa. Following 8 weeks of flooding, four of the taxa: I. cornuta `Burfordii', I. × `Nellie R. Stevens', I. cassine, and I. × attenuata `Foster's #2' performed remarkably well during and after flooding with photosynthetic rates > 40% of the controls, root ratings >75% of the controls, <5% of the foliage showing deterioration, and 100% survival. Conversely, I. crenata `Convexa', Ilex × meserveae `Blue Princess', I. rugosa and I. aquifolium `Sparkler' did not tolerate flooding well as indicated by severely depressed photosynthetic rates, deterioration of foliage and roots, and decreased survival. The remaining taxa were intermediate.0
Inheritance and Evolution of the Cucurbit Organellar Genomes
Authors: Havey M.J. , McCreight J. , Rhodes W. , Taurick G.
Published: February 2019

The cucurbits have several-fold size differences in their mitochondrial genomes. Watermelon possesses a relatively small mitochondrial genome of 330 kb. Squash has a larger mitochondrial genome of 840 kb. Cucumber and melon possess huge mitochondrial genomes of 1500 and 2400 kb, respectively. We demonstrated predominately paternal transmission of the mitochondrial genome in cucumber. Squash shows maternal transmission of the chloroplast genome. We generated reciprocal crosses and identified restriction fragment length polymorphisms in the chloroplast and mitochondrial genomes of melon, squash, and watermelon to establish their transmission. Our analyses also revealed that intergenomic transfers contributed to the evolution of extremely large mitochondrial genomes.
Interaction of Genes for Flesh Color in Watermelon
Authors: Henderson Warren R. , Scott Gregory H. , Wehner Todd C.
Published: February 2019

Watermelon [Citrullus lanatus (Thunb.) Matsum. & Nakai] flesh color is controlled by several genes to produce red, canary yellow, salmon yellow, and orange. Our objective was to study the interaction of three gene loci with two or three alleles at each C (canary yellow vs. red), y (salmon yellow vs. red), yo (orange), and i (inhibitory to C permitting Y to produce red flesh color). Five crosses were used to study gene action: `Yellow Baby' × `Sweet Princess', `Yellow Baby' × `Tendersweet Orange Flesh', `Yellow Baby' × `Golden Honey', `Yellow Doll' × `Tendersweet Orange Flesh', and `Yellow Doll' × `Golden Honey'. Based on the performance of six generations (PA, PB, F1, F2, BC1A, and BC1B), the parents had the following genotypes: `Yellow Baby' = CCYYII, `Yellow Doll' = CCYYII, `Sweet Princess' = ccYY ii, `Tendersweet Orange Flesh' = ccyoyoII, and `Golden Honey' = ccyyII. Segregation of flesh colors in the progeny of the five families demonstrated that there was a multiple allelic series at the y locus, where YY (red) was dominant to yo yo (orange) and yy (yellow). Also, yoyo was dominant to yy. In conclusion, epistasis is involved in genes for the major flesh colors in watermelon, with ii inhibitory to CC (Canary), resulting in red flesh, and CC in the absence of ii epistatic to YY, producing canary flesh.
Evaluation of the Luffa Germplasm Collection for Sponge Yield and Quality
Authors: Ellington Tammy L. , Wehner Todd C. , Davis Jeanine M.
Published: February 2019

All available luffa (Luffa aegyptiaca Mill.) cultivars, breeding lines, and plant introduction accessions (collectively referred to as cultigens hereafter) were evaluated at Clinton, N.C., over 3 years. Plants were grown in plots 1.5-m-long on a 1.8-m-high trellis. Border rows and tiers on the sides and ends of the trial were used to reduce the edge effect. Plots were planted in May and evaluated for vine height and sex expression. Fruit were harvested in October to determine fruit number and length after frost killed the vines. Sponges were processed from the fruit and evaluated for seed cell number, wall thickness, sponge strength, fiber denseness, and other quality traits. The tallest vined cultigens were PI 286425 and Fletcher, and the shortest vined were PI 381869 and PI 540921. The highest yielding (sponge number per hectare) cultigens were PI 540921 and PI 391603, and the lowest yielding cultigens were Luffa 30310 and Luffa 97321. Of the cultigens tested, PI 391603 had the longest fruit overall, whereas PI 540921 had the shortest.
Fine Root Production and Mortality in Apple over Winter
Authors: Wells Christina E. , Eissenstat David M.
Published: February 2019

Fine root lifespan has previously been estimated at 3 to 4 weeks for apple trees growing in England. We used nondestructive belowground imaging technology to investigate the accuracy of this estimate for apple trees growing in central Pennsylvania. Eight root observation tubes (minirhizotrons) were installed beneath each of six 20-year-old `Red Delicious' apple trees on M26 rootstock. Videos of roots growing against the tubes were taken at intervals of 14 to 28 days between October to June, depending on the amount of root activity. Images were used to construct a database of life history information for over 500 individual roots. A flush of fine roots was produced in the early fall, followed by a period of low but constant mortality that lasted through December. Roots that survived to this time were generally maintained throughout the winter and following spring. A second flush of root production occurred in the spring, coinciding with bud burst and flowering. Root mortality was highest in late spring following this flush. In contrast to earlier estimates of apple root lifespan, we found that >30% of the fine roots produced in the fall lived for ≥200 days. Most of these roots developed red-brown pigmentation, a feature that previously has been associated with cortical cell death. However, the ability of these pigmented roots to produce new white laterals in the spring argues against categorizing these as dead roots. The information on root demographics provided by this study adds to our understanding of seasonal carbon and nutrient allocation patterns in apple.
Temperature Effect on Nut Filling in Three Pecan Cultivars
Authors: Sistrunk Laurence , Chapman Dan , Storey J. Benton
Published: February 2019

The influence of temperatures during nut filling on nut size, kernel percentage, kernel color, percent oil, and fatty acid composition were evaluated over 3 years in `Cheyenne', `Mohawk', and `Pawnee' pecans [Carya illinoenensis (Wangenh.) C. Koch]. Nuts were harvested at shuck split at 14 sites located in Texas, Oklahoma, Kansas, Nebraska, Arizona, and California and Coahuila, Mexico. Weather data for 12 weeks before shuck split at each site were used to determine degree days by the formula: degree days = summation n(m–t) where n = number of days, m = (max + min temperature) ÷2, and t = 10°C. The degree days ranged from 996 to 1675. The oleic: linoleic ratios in all three cultivars were positively correlated with degree days in 2 of 3 years. `Mohawk' nut size was positively correlated with degree days all 3 years and `Cheyenne' and `Pawnee' were larger 2 of 3 years in the warmer climates. `Pawnee' kernel percentage and oil content was higher in the warmer climates. Warmer developmental temperatures had no influence on `Cheyenne' kernel color. `Mohawk' kernels were not affected 2 of 3 years, but `Pawnee' developed darker colors 2 of 3 years.
Using Banana Peel for Bioassay Development to Evaluate the Retardation of Senescence by Lysophosphotidylethanolamine, A Natural Lipid
Authors: Workmaster Beth Ann A. , Palta Jiwan P.
Published: February 2019

Recent work in our laboratory has shown that pre- and postharvest applications of lysophosphotidylethanolamine (LPE) retard senescence processes in several fruit and flower species (apple, tomato, carnation). Banana was selected to develop a rapid bioassay to test the effects of LPE and other substances on various processes associated with senescence. Excised peel pieces from fully yellow `Grand Nain' bananas (Musa AAA) were incubated in petri dishes containing LPE solution (0, 25, 50, and 100 ppm) for 4 days. Fresh weight and ethylene production was measured daily. At the end of the experiment, tissue density, ion leakage, and soluble protein leakage was measured. Ion and soluble protein leakage was significantly lowered with 100 LPE. The 100 ppm LPE also significantly inhibited ethylene production after only 2 hours of treatment and this low level was maintained during the experiment. Peel tissue from the 100 ppm LPE remained firm and intact while tissue from the other treatments expanded and lost integrity. By day 2, peel from the 0, 25, and 50 ppm LPE gained significantly in fresh weight, while tissue treated with 100 ppm initially lost and then only slightly gained in fresh weight. Our results suggest that LPE is able to protect membrane function in senescence. Furthermore, these results provide evidence that LPE may also be retarding senescence by modulating the ethylene pathway.
Harvesting and the Incidence of Green Mold on Texas Grapefruit
Authors: Fucik John E.
Published: February 2019

The harvest of Rio Red grapefruit (Citrus paradisi Macf.) was “intercepted” at three stages: 1) unpicked fruit, 2) picked and carried to pallet box trailer, and 3) picked, carried, dumped in the pallet box and transported to the packing shed. Three harvesters picked fruit from four canopy locations on two trees each. At each intercept, half the fruit was dipped into a spore solution of green mold (Penicillium digitatum) and half left nontreated as controls. Intercept 1 fruit was dipped and left unpicked on the tree. After 10 days incubation, the rate of green mold infection and its location on the fruit was determined. Tests were run in May 1995 and Feb. and Apr. 1996. The rate of infection increased with each intercept, and treated fruit had 15 times the infection rate of the controls. The highest infection rate, 1.3%, occurred in May 1995 followed by Feb. (0.8%), and April (0.5%). Most infection sites appeared above and below the fruit's equator, rather than on its top or bottom exclusively. There were no effects associated with harvesters or the location of the fruit in the canopy.
Effects of Fertilizer Additions on Growth of Cotoneaster dammeri and Rudbeckia fulgida in Composted Turkey Litteramended Pine Bark Substrates
Authors: Tyler Helen H. , Warren Stuart L.
Published: February 2019

An experiment with a factorial treatment combination in a split plot design with five single plant replications was conducted to evaluate the effects of five rates of fertilizer addition and two irrigation volumes on plant growth in a composted turkey-litter-amended pine bark substrate. Main plots were daily applications of 600 or 900 ml/3.8-L container. Subplots were either 0, 1.0, 2.0, 3.0, or 4.0 g N additions (Osmocote High H 24N–1.7P–5.8K) per container topdressed on a substrate composed of pine bark amended with 8% (by volume) composted turkey litter. No additional amendments were made to the compost amended substrates. An additional “industry control” treatment consisted of an 8 pine bark: 1 sand (by volume) substrate amended with 3.0 kg/m3 dolomitic limestone and 0.9 kg/m3 Micromax and topdressed with 3.5 g N (Osmocote High N) per container. After 134 days, Cotoneaster dammeri `Skogholm' and Rudbeckia fulgida `Goldsturm' plants were harvested and shoot and root (cotoneaster only) dry weights were determined. Cotoneaster shoot and root dry weights and rudbeckia shoot dry weight increased linearly as N rate increased from 0 to 4.0 g N. Irrigation volume did not affect cotoneaster shoot or root dry weights. Rudbeckia shoot dry weight was 18% greater with 900 ml than with 600 ml of irrigation. Rudbeckia growth in compost amended substrate was greater than in the industry control when topdressed with ≥1.0 g N. Shoot growth of cotoneaster in the industry control substrate and compost amended substrate with ≥ 3.0 g N applied was similar.
Horticulture/Gardening in Kindergarten through Fifth and Sixth Grade Education in Virginia: A Survey of Teachers
Authors: Dobbs Kathleen , McDaniel Alan
Published: February 2019

In Spring 1995, a survey was conducted on horticulture/gardening in Virginia kindergarten through fifth and sixth grades (K–5/6). Ten questionnaires and cover letters were sent to each of 100 randomly chosen elementary schools of the 1143 elementary schools representing ≈45,000 teachers throughout Virginia. Based on a 33.7% response rate from a self-selected group of K–5/6 teachers in Virginia, there is a relatively high level of interest (87.5% of respondents were interested) regarding using horticulture/gardening in the classroom. To facilitate incorporating horticulture into the curriculum for the widest number of teachers, teaching packets containing horticulture-based lesson plans, activity ideas, posters, and AV materials should be prepared. However, it is likely that using these prepared resources alone will result in a minimum amount of integration of horticulture/gardening in the classroom. Materials should be presented to interested teachers at a local class or in-service where they can be reviewed and teachers are able to address any concerns or needs they may have. A follow-up outreach should be done in the form of monthly newsletters: one for the teachers containing new ideas on using horticulture in the classroom and one for students with horticulture-based activities and information. Additionally, the need for preservice undergraduate and postservice graduate level horticulture courses offered by Virginia Tech for teachers should be explored.
Production of Interspecific Hybrids between Hexaploid Fragaria moschata and the diploid species F. nubicola and F. viridis.
Authors: Bors Robert H. , Sullivan J. Alan
Published: February 2019

Interspecific crosses with Fragaria moschata (6x) have been hampered by ploidy level differences, poor seed set, and extremely poor seed germination. Modification of pollination practices, embryo rescue, and use of several genotypes has allowed over 80 synthetic tetraploids to be created from 14 cross combinations. Germplasm for the experiment consisted of eight selections of F. moschata (6x), two of F. nubicola (2x), and two of F. viridis (2x). Both 2x × 6x and 6x × 2x crosses were performed. Initially, negligible seed set occurred on F. nubicola and F. viridis when multiple flowers per truss were pollinated. When only one cross was performed per truss, with other flowers removed, seed set was greatly enhanced. F. moschata was much more tolerant of multiple crosses per truss. The crossing combination of F. moschata × F. nubicola gave the worst seed production. Other species combinations were capable of producing good seed set with noticeable differences between individual selections. When achenes were halved, only 1% appeared normal, 2% were underdeveloped or shrunken, the remainder were empty. Many of the malformed and most of the normal embryos germinated using the cut achene method. Achenes were surface-sterilized, cut in half, and placed on MS media with activated charcoal (3g·L–1), sucrose (30g·L–1), and no hormones. Germination occurred only from achenes from fully ripened fruit. Viable hybrids were obtained from 2x × 6x as well as 6x × 2x crosses. Fragaria viridis–F. moschata hybrids closely resembled F. moschata while F. nubicola–F. moschata hybrids were more intermediate in leaf morphology.
Utility of Shrimp Sludge from Organic Aquiculture Lagoons as a Soil Amendment for Broccoli Production
Authors: Dufault Robert J. , Hopkins S. , Sandifer P.
Published: February 2019

Our objectives were to determine 1) if shrimp sludge has any value as a soil amendment in broccoli production and 2) an appropriate rate of sludge for head production. Four levels of N–P–K per 15-L pot (in grams; 2.0 N–0.07 P–1.4 K; 4.0 N–0.14 P–2.8 K; or 6.0 N–0.21 P–4.2 K; and 0.0 N–P–K) were factorially combined and replicated 10 times with four volumes of shrimp sludge (0%, 10%, 20%, and 40% v/w in 15-L pots blended with 100%, 90%, 80%, and 60% Metro Mix 300, respectively). Four-week-old `Emerald City' broccoli transplants were planted into sludge + media–fertilizer mixtures on 12–14–95 and were grown to harvest maturity in a greenhouse. As sludge volume increased, the days to harvest, plant height, and root fresh weight: head fresh weight ratio decreased, but leaf number, fresh weight and area, head fresh weight, stem diameter, and shoot: root fresh weight ratio increased. As N–P–K rate increased, leaf number, area, and fresh weight, stem diameter, head fresh weight, and shoot: root fresh weight ratio increased, but root: head fresh weight ratio and plant height decreased. Using head fresh weight as the determinant, heaviest heads were optimized with 20% sludge and 4.0g N–0.14g P–2.8g K per 15-L pot. Sludge alone or N–P–K alone did not produce the heaviest broccoli heads as using combinations of sludge and N–P–K in a fertility program.
Improving Garlic Using Wheat Straw Mulch
Authors: O'Callaghan Angela M.
Published: February 2019

Garlic (Allium sativum L.) has been cultivated in much of the world for millennia. Little scientific research, however, has focused on improving cultural conditions for production in the temperate regions of the northeastern United States, where garlic is gaining importance as a horticultural crop. To study the effectiveness of wheat straw (Triticum aestivum) mulch on garlic, experiments were conducted at the Cornell Univ. research facilities in East Ithaca, N.Y., during the 1993–94 (year 1) and 1994–95 (year 2) growing seasons and at the Homer C. Thompson Vegetable Research Farm, Freeville, N.Y., during the 1994–95 growing season. Two clones, one bolting and one nonbolting, were studied in year 1, and four varieties, three bolting and one non bolting, in year 2. All were fall-planted (mid-October), and mulch treatments were covered with wheat straw early in the following December. Control plots were not covered. The mulch either remained on the crop throughout the growing season or was removed early in the spring to expedite soil warming. This is the common practice among growers who use mulch only for winter protection. The presence of mulch during the winter increased the survival rate. Soil temperatures under the wheat straw were significantly lower during the summer than soil temperatures in unmulched plots, which could have contributed to the increase found in the yield and average bulb size of several of the cultivars. Maintaining the mulch through the entire growing season reduced weed pressure >30%. We found no significant increase in the amount of basal fungal infection. The results indicate that using straw mulch can improve garlic produced in the northeastern United States.
Gas Exchange in Tomato in a Cover Crop–Tomato Cropping System
Authors: Whitehead Wayne F. , Singh Bharat P.
Published: February 2019

Our objective was to determine the effect of cover crops on the gas exchange activities of a succeeding crop of tomato. No commercial N fertilizer was applied, and the mineralization of cover crops provided the sole source of supplemental N for the tomato crop. Cover crops were planted in randomized complete blocks on 8 Sept. 1994, with treatments consisting of control (fallow), rye, hairy vetch, and crimson clover. A tomato cultivar Mountain Pride was transplanted in the field on 18 Apr. 1995. The gas exchange rate of tomato was measured at flowering (6 June), fruiting (13 July), and senescence (10 Aug.) with infrared gas analyzer using a steady-state gas exchange system. The highest stomatal conductance (gs) and CO2 exchange rate (CER) was obtained during flowering and fruiting, respectively. The tomato plant following a legume cover crop conducted water vapor at a significantly higher rate than those preceded by rye or fallow. The CER of tomato planted behind a legume cover crop was also higher compared to those following rye or fallow. The gs ranged from 384 to 1146 mmol·m–2·s–1, and CER varied from 5.7 to 17.8 mol·m–2·s–1 depending on the preceding cover crop and the stage of growth of the tomato plant. From the results of this study, it was apparent that, while legume cover crops increased the gas exchange activities of the ensuing tomato crop, nonlegumes had no such effect.
Molecular Mapping and Tagging of Cucumber Mosaic Virus Resistance Genes in Capsicum
Authors: Zhang Yiping , Lackney Vince , Kyle Molly
Published: February 2019

Genetic resistance to cucumber mosaic virus (CMV) in pepper (Capsicum spp.) is recessive, polygenic and, therefore, has been difficult to transfer in breeding programs. Although a few varieties have been released with some resistance, in our tests, these develop severe symptoms that are eventually indistinguishable from the susceptible reactions. Furthermore, accurate and consistent screens for the disease can be relatively difficult; therefore, we report on the detection molecular markers linked to two CMV resistance genes using distributional extreme analysis to identify the relevant quantitative trait loci (QTL). The 12 most resistant and 15 most susceptible individuals were selected from a segregating F2 population of 316 individuals that were derived from the interspecific cross (C. annuum `Jupiter' × C. frutescens BG2814-6). A total of 132 tomato genomic, cDNA, and pepper genomic clones were hybridized to filters with DNA extracted from the distributional extremes. These clones included framework markers representing all pepper linkage groups and also selected clones from regions of the genome identified in a preliminary analysis as possibly involved with CMV resistance. Several clones from the two regions of the genome previously identified appear to be nonrandomly cosegregating with the CMV resistance phenotype in this larger population. Further analysis will be done by adding more markers in the regions and refining the positions of the resistance QTL.
Growth Characteristics and Response to Nitrogen Fertilizer of Some Morphotypes of Jute Marlow (Corchorus olitorius Linn.)
Authors: Makinde M.J. , Ayanlaja S.A.
Published: February 2019

Plant growth characteristics were observed for 12 morphotypes of Corchorus olitorius planted in the field. Two commonly used varieties in Nigeria were subjected to increasing nitrogen fertilizer rates. Extensive variations in measured leaf, stem, and root growth confirmed genetic diversity among morphotypes. Thus, fresh shoot harvest l00 kg N/ha at 3 kg/ha seed rate for the lanceolate was 17.44 t·ha–1, the serrate-type at the same seed rate required N at 200 kg·ha–1 to produce 18.19-ha harvest.
Effects of Broccoli Donor Genotype on Incidence of Diploids in Populations Regenerated from Anther Culture
Authors: Farnham Mark W.
Published: February 2019

Broccoli (Brassica oleracea L. Italica group) breeders are increasingly using anther or microspore culture to produce dihaploid (diploid), homozygous lines for use in making hybrids. During the process of anther culture and subsequent plant regeneration, wherein embryos develop from microspores and plants are regenerated from the embryos, polyploidization occurs and diploid regenerants can result. However, polyploidization may not occur at all, or it may involve a tripling or quadrupling of the chromosome complement, instead of a doubling. Thus, populations may contain haploids, triploids, or tetraploids, in addition to diploids. In two cycles (1994-95 and 1995-96) of anther culture, regenerated populations from different broccoli hybrid sources were evaluated using flow cytometry to facilitate efficient identification of diploids vs. haploids, tetraploids, or others and to determine if anther donor genotype has an effect on the frequency of different ploidy levels among regenerants. In the first cycle, five broccoli hybrids had anther-derived populations in which ≈33% were haploid, 55% diploid, 37% tetraploid, and 5% aneuploid or abherent types. The hybrid, `Marathon', was different; it's regenerants were 78% diploid and only 15% tetraploid. In the second cycle, anther-derived populations had a significantly different makeup with a most hybrids giving 30% to 40% diploids and 50% to 60% tetraploids. However, consistent with the previous cycle, `Marathon' gave significantly more diploids (68%) and fewer tetraploids (25%) than other hybrids. These results indicate that anther donor genotype affects ploidy frequency among regenerants. Genotypes producing a high frequency (>60%) of diploids may be relatively uncommon.
Fertilization Rate and Growth of `Hamlin' Orange Trees Related to Preplant Leaf Nitrogen Levels in the Nursery
Authors: Guazzelli Laura , Davies Frederick S. , Ferguson James J.
Published: February 2019

Our objectives were to determine if leaf N concentration in citrus nursery trees affected subsequent growth responses to fertilization for the first 2 years after planting and how N fertilizer rate affected soil nitrate-N concentration. `Hamlin' orange [Citrus sinensis (L.) Osb.] trees on `Swingle' citrumelo rootstock [C. paradisi Macf. × P. trifoliata (L.) Raf.] were purchased from commercial nurseries and grown in the greenhouse at differing N rates. Three to five months later trees were separated into three groups (low, medium, high) based on leaf N concentration and planted in the field in Oct. 1992 (Expt. 1) or Apr. 1993 (Expt. 2). Trees were fertilized with granular material (8N–2.6P–6.6K) with N at 0 to 0.34 kg/tree yearly. Soil nitrate-N levels were also determined in Expt. 2. Preplant leaf N concentration in the nursery varied from 1.4% to 4.1% but had no effect on trunk diameter, height, shoot growth, and number or dry weight in year 1 (Expt. 1) or years 1 and 2 (Expt. 2) in the field. Similarly, N fertilizer rate had no effect on growth during year 1 in the field. However, trunk diameter increased with increasing N rate in year 2 and reached a maximum with N at 0.17 kg/tree yearly. Shoot number during the second growth flush in year 2 was much lower for nonfertilized vs. fertilized trees. Leaf N concentrations increased during the season for trees with initially low levels even for trees receiving low fertilizer rates. Soil nitrate-N levels were highest at the 0.34-kg rate, and lowest at the 0.11-kg rate. Nitrate-N levels decreased rapidly in the root zone within 2 to 3 weeks of fertilizing.
The Effect of Varying Cultural Practices on the Location of Mycorrhizal Infection within the Rhizosphere of Highbush Blueberry Plants
Authors: Goulart B.L. , Demchak K. , Yang W.Q.
Published: February 2019

Previous experiments in the laboratory and the field have suggested that location of mycorrhizal infection within the rhizosphere of blueberry plants may depend on cultural practices that are being used. Furthermore, we have observed that rapidly growing roots, whether in solution culture or within petri dishes, appear to be less likely to become infected when inoculated. A preliminary experiment found higher levels of mycorrhizal infection in roots growing at a 5-cm depth of soil compared to roots growing just under the mulch layer. To further test this hypothesis, an experiment was designed to evaluate the infection intensity of highbush blueberry plants (Vaccinium corymbosum L.) at different locations within the rhizosphere on plants growing under varying cultural practices. Cultural practices included mulching (mulch vs. no mulch) and nitrogen level (0 and 120 g ammonium sulfate/plant). Four-year-old `Bluecrop' highbush blueberry plants subjected to these treatments were arranged in a complete factorial design with six replications at the Russell E. Larson Agricultural Research Center at Rock Springs, Pa. Mycorrhizal infection intensity was evaluated from roots sampled nondestructively using a 2.5 cm soil corer at the interface of the mulch and soil, and at soil depths of 3 and 15 cm from two locations 15 cm from the crown of each plant. Results will be discussed.
Effect of Foliar Application of Urea and Boric acid on Red Roomy Grapevines: II. The Effect on Yield and Quality of the Berries
Authors: Akl A.M. , Wassel A.M. , Ahmed F.F. , Hady M.A. Abdel
Published: February 2019

This investigation was conducted during the 1991, 1992, and 1993 seasons to study the effect of different concentrations and number of sprays urea and/or boric acid on yield and berries quality of Red Roomy grapevines. Two, three, four, or five sprays for both urea at 0.5% 1%, or 1.5% and /or boric acid at 0.1%, 0.2%, or 0.3% in addition to the control treatment were applied. Combined sprays of urea and boric acid was preferable in increasing the number of clusters, yield per vine, berry set parentage, fertility coefficient. weight, length and shoulder of cluster, weight and dimensions of berry, total soluble solids, total sugars, and total anthocyanins in grapes and in reducing the percentages of cracked and shot berries and the total acidity compared with the single application of both. Spraying urea at 1.0% in combined with boric acid at 0.2% four times (i.e., at growth start, first bloom, immediately after berry set, and at 30 days later) is recommended for achieving high yield and fairly good berries quality in `Red Roomy' grape vines.
Biochemical and Molecular Characterization of a β-1,3-Endoglucanase from Valencia Orange Callus
Authors: McCollum T. Gregory , Doostdar Hamed , Burkhart Michael , Neidz Randall , Mayer Richard T. , McDonald Roy E.
Published: February 2019

Inhibition of the growth of fungal pathogens has been related to levels of a β-1,3-endoglucanase (EC 3.2.1.39) (GLU) in citrus as well as other plant species. Our long-term objective is to transform Citrus spp. to express enhanced levels of GLU with the aim of increasing resistance to fungal pathogens. We have purified a β-1,3-endoglucanase from nonembryogenic Citrus sinensis (L.) Osbeck cv. Valencia callus to electrophoretic homogeneity by means of pH precipitation and ion exchange chromatography. The protein has an apparent Mr of 32.5 and a pI > 10. The enzyme hydrolyzes laminarin (Laminaria digitata) optimally at pH 5 and 50°C. The enzyme will hydrolyze any glucan polymer with a β-1,3 linkage whether soluble or insoluble and the rate of hydrolysis is proportional to the relative abundance of β-1,3 linkages. The enzyme does not hydrolyze cellulose or starch. Product characterization by thin-layer chromatography indicates that the enzyme is an endohydrolase. Initial attempts to sequence the protein indicated that it was N-terminally blocked. Therefore the protein was hydrolyzed using AspN, the fragments separated by SDS-PAGE, blotted onto nitrocellulose, and one of the fragments was sequenced. Amino acid sequence analysis indicated that the protein shared homology with a number of β-1,3-endoglucanases. Antibody to the purified protein was raised in rabbits and used to screen an amplified cDNA library prepared from Citrus sinensis (L.) Osbeck cv. Valencia callus. One of the positive clones was selected and sequence analysis indicated that the clone was homologous with other β-1,3-endoglucanases.