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  • Author or Editor: Charles Johnson x
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Influence on productivity of `Harvester' peach trees to three methods of preplant soil preparation were studied for five years. The three methods were as follows: 1) a backhoe was used to prepare the soil, 2) a turn-plow, and 3) no preparation. Trunk yield data were taken after the first three growing seasons. There were no significant treatment differences for yield at the .05 level of probability. Trends show an increase in yield using the turn-plow and the backhoe method showed better early tree growth, but by the fifth year, there were no apparent differences.

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Inheritance of dark green stripe and light green rind color in watermelon was investigated. Controlled crosses were made between watermelon cultivars: `Louisiana Sweet'-light green rind with dark green stripe; `Calhoun Sweet'-dark green rind without stripes; and `Charleston Gray' and `Calhoun Gray' both having light green rind without stripes. Plants of parental, F1, F2, and BC lines were classified as to rind color and presence or absence of stripe. All F1 progenies produced only striped fruit. Chi Square analysis of F2 and BC generations corresponded to 3:1 and 1:1 ratios respectively, for stripe:no stripe, indicating dark green stripe was controlled by one dominant gene. The cross `Louisiana Sweet' × `Calhoun Sweet',(light green × dark green rind color), resulted in F1 and F2 progeny having only dark green rind fruit, indicating obvious dominance for dark green rind color. Segregation in BC populations indicated a single dominant gene for dark green rind color; however, lack of segregation in the F2 suggests additional factors may be involved.

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The influence of N and K rates in Hoagland's nutrient solution on Jalapeño pepper (Capsicum annuum L.) plant growth and pod production was determined on greenhouse-grown plants in sand culture. Varying the rates of N (1 to 30 mm) and K (1 to 12 mm) in Hoagland's solution identified optimum concentrations for Jalapeño plant growth and pod production. Two experiments were conducted to determine Jalapeño pepper sensitivity to differential fertilization. In the experiment seeded in April, nutrient treatments began at transplanting, and in the one seeded in May, treatments began after all plants had flower buds and half had flowered. Biomass and pod production per plant responded curvilinearly to N rate in both experiments. Optimum N rate for pod yield was 15 mm. Nitrogen rate affected pungency of pods only in the first experiment, with 1 mm N reducing capsaicin levels in fruit compared to other N rates. Biomass, fruit count, and fruit weight per plant increased linearly with increasing K rate in the first experiment and curvilinearly with K rate in the second experiment. The optimum K rate for pod yield was 6 mm. Potassium rates did not affect pod pungency. Jalapeño peppers grown in sand culture required 15 mm N and at least 3 mm K for optimum pod production.

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Abstract

Root systems of Pittosporum tobira Thunb. plants were exposed to temperatures of 27°, 30°, or 40°C for 6 hours daily for 7 months. Top and root growth, root carbohydrate levels and photosynthetic rates were reduced by the 40° treatment. Content of K, Fe, and Zn in leaf tissues were reduced at highest root temperatures, while N content showed the opposite response.

Open Access

Maintenance of genetic resources within the National Plant Germplasm System includes preserving the genetic constituency of accessions as close to the original sample as possible. Genetic changes that can arise during seed regeneration include both an overall loss of genetic diversity within heterogenous accessions and changes in the gene frequencies within accessions. Two germplasm collections are being examined with molecular methods at the Western Regional Plant Introduction Station (WRPIS) for evidence of such genetic change. In the case of pea, gross observation of seed and plant characters indicate that vigorous plant culling during a comprehensive Pea Seedbourne Mosaic Virus eradication program a decade ago resulted in the overall loss of genetic diversity in some heterogenous accessions. Isozyme data has corroborated these observations. Molecular markers are beginning to be used, both to quantify possible genetic changes in accessions as a result of the eradication process, and to document success in reintroducing diversity by repeating the eradication process with additional seed from archival seedlots. In the case of ryegrass, the practice of bulking the seed harvested from regeneration plots may bias the seedlot toward genotypes that are more fruitful. Isozyme analysis after two regeneration cycles showed that balanced sampling (equal seed no./plant) maintained allele frequencies close to the original seed sample. A bulk harvest sample and a sample with an equal number of spikes harvested from each plant showed some significant change in allele frequency, but no significant changes were seen in the allelic richness of accessions, or in the level of an accession's overall heterozygosity. A regeneration sample with an equal number of seed/plant will therefore best preserve gene frequencies within accessions, but loss of an accessions overall diversity will not diminish as a result of less than ideal sampling methods in ryegrass.

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During the summer of 1988, a study was conducted to determine the effect of an inexpensive reusable styrofoam container on the percent weight loss in collards (bunch and head) after 30 days in a walk-in cooler. This container was designed and constructed for precooling, shipping, and storing fruits and vegetables. The insulated container was provided with a lid-mounted ice cavity that was removable and could be replaced through an access door without removing the lid. The ice cavity melted and was dispersed throughout the container onto the collards. The three treatments used in this study were (1) no top (2) top without ice, and (3) top with ice. Results indicated that both the bunches and heads responded similarly to treatments. The top with ice treatment significantly reduced percent weight loss when compared to the other treatments (top no ice and no top).

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Growth in juice-based products is supported by an increasing consumer base, which perceives fruit and fruit-based beverages as an integral component of nutritious food types that can benefit health. New flavor combinations, as well as added ingredients (i.e., vitamins) continue to help boost juice appeal as a nutraceutical. New juice-based food products such as blends, jellies, marinades, and pastry fillings could benefit from the unique flavor attributes specific to mayhaw fruit juice. Juice from one cultivar of muscadine grape (Vitisrotundifolia Michx.) `Carlos' (bronze skinned) was mixed with varying levels of juice from one cultivar of mayhaw (Crataegusopaca) `Texas Star' (reddish-orange skinned) fruit. Five different blend combinations were tested for both individual juice quality and for juice-blend compatibility. A consumer preference test was conducted (n = 75) on a 9-point hedonic scale for color, taste, and overall liking. Next to the taste/flavor preference scores for control (6.8), mayhaw juice used as the primary flavor ingredient in blends was the second most preferred of all juices by the panelists. A 50/50 juice blend and 70/30 mayhaw/muscadine blend were the least desirable of the five combinations tested. Juices from 60/40, 30/70, and 40/60 mayhaw/muscadine were considered by the panelists as best in flavor and overall acceptability. “Taste” had the strongest effect on overall acceptability of juice from varying levels of mayhaw juice in combination with muscadine grape juice. Panelists' mean score averages collectively were favorable of 60:40 and 50:50 juice blends and were significant (P < 0.05) toward acceptance of a “mayhaw-muscadine” fruit juice blended drink.

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