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  • Author or Editor: R. E. Williamson x
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Abstract

Fruits of rabbiteye blueberry (Vaccinium ashei Read cv. Tifblue) were harvested by hand and an overrow mechanical harvester for 2 years. Machine harvest increased ground loss of marketable fruit over hand harvest. Hand-harvested fruit were 29 to 37% firmer than machine-harvested fruit. When held for 7-11 days at 15.5°C, machine-harvested fruit had more than twice the amount of soft and unmarketable fruit than hand-harvested fruit. Pruning rabbiteye blueberry plants increased the harvesting efficiency of the machine.

Open Access

Abstract

Seed of snap bean, Phaseolus vulgaris L. cv. Avalanche were separated into 3 length or 3 diameter groups and then each group separated into 3 classes based on aerodynamic properties. The grading procedure resulted in seed grades having large differences in physical characteristics, growth and yield responses. Yield response potential of snap bean was determined primarily by seed weight. A grading method utilizing size grading based on seed diameter followed by aspiration in a vertical air column was the most effective method of eliminating seed with low yield potential.

Open Access

Abstract

Root growth of cucumber (Cucumis sativus L.) was not greatly restricted by soil strength less than 500 kPa (5 bars). Root growth was inhibited 80% at a soil strength of 850 kPa. Mechanical compaction produced by a tractor wheel resulted in a 50% reduction of tissue NO3 at comparable soil NO3 levels, a 25 to 35% yield reduction, and a decrease in fruit length/diameter ratio. The effects of soil compaction could be partially alleviated by increasing the rate of nitrogen fertilization; however, a 3-fold increase in N fertilization did not completely counteract the effect of compaction on cucumber yield. A system for cucumber seedbed preparation which reduces soil compaction is presented.

Open Access

Abstract

Coated seed of tomato (Lycopersicon esculentum Mill.) were precision seeded at 4 rates and 3 patterns to determine the effects on size variation of field-grown transplants. No significant differences in the number of marketable or cull transplants were obtained with the 3 planting patterns. Seeding rates greater than 63 seeds/m usually increased the number of cull transplants with no significant increase in the number of marketable transplants. About 20% more marketable transplants were produced in the 2 inside rows than in the 2 outside rows on 4 row beds.

Open Access

Abstract

Removal of 20% of the seed of a commercial ‘Poinsett’ seed lot in a vertical air column increased the mean thickness and weight of the remaining seed. Fruit yield was increased by use of thicker, heavier seed when yield potential was not limited by high soil strengths. Seed grading effect on cucumber yield was less when either soil compaction or climactic conditions reduced yield potential. A combination of both yield limiting factors eliminated seed grading effect. Yield response to source of nitrogen was different when cucumbers were grown on compacted and noncompacted seedbeds. An interaction of seed grade, nitrogen source and seedbed compaction on marketable fruit yield was found.

Open Access

Abstract

Plant and root growth and root distribution of ‘Dixie’ squash (Cucurbita maxima Duch.) were reduced by mechanical soil compaction of a Tifton loamy sand soil. Soil atmospheric O2 and CO2 concentrations were not affected by soil compaction. Marketable fruit yield was reduced 46 to 58% by increased soil strength produced by tractor wheel traffic. Nitrogen from Ca(NO3)2 produced greater yields in non-compacted plots and smaller yields in compacted plots than NH4NO3.

Open Access

Abstract

Cabbage, Brassica oleracea, var. Capitata L.; squash, Cucurbita pepo Alef.; and tendergreen, Brassica perviridis Bailey were grown at various water table depths in sheltered soil tanks on a fine sandy loam and a loam soil to evaluate the effects of high water table and soil type on growth and yield of these vegetable crops. Yields of the 3 species increased with water table depth to a depth of 76 to 102 cm. On both soil types the 15-cm water table depth caused considerable yield reduction and chlorosis for the 3 species. For maximum yields deeper water table depths were needed with loam than with sandy loam soil. Yield of cabbage was not significantly increased at water table depths greater than 30 cm in either soil. Squash yield was highest at water table depths of 61 to 76 cm in the fine sandy loam and 91 to 102 cm in the loam soil. Tendergreen yield was not significantly increased by water table depths greater than 61 cm in either soil.

Open Access

Abstract

Seed of 11 cultivars of snap bean, Phaseolus vulgaris L., were separated by aerodynamic properties in a vertical air column. Seed physical characteristics associated with air column separation were weight, density, volume, diameter, and length. The separation technique did not affect seed germination, seedling emergence, or plant survival at full expansion of the first trifoliate leaf growth stage. However, seed remaining in the air column after aspiration produced fewer weak plants and fewer plants with root rot at the first trifoliate leaf. These seed produced a greater plant stand, a greater pod weight per plant, a more uniform pod size distribution, and a greater yield at harvest than the seed removed. Yield from seed remaining after air column aspiration was 21% greater than from non-graded seed.

Open Access

Floral budbreak and fruit set in many southern highbush blueberry (SHB) cultivars (hybrids of Vaccinium corymbosum L. with other species of Vaccinium) begin prior to vegetative budbreak. Experiments were conducted with two SHB cultivars, `Misty' and `Sharpblue', to test the hypothesis that initial flower bud density (flower buds/m cane length) affects vegetative budbreak and shoot development, which in turn affect fruit development. Flower bud density of field-grown plants was adjusted in two nonconsecutive years by removing none, one-third, or two-thirds of the flower buds during dormancy. Vegetative budbreak, new shoot dry weight, leaf area, and leaf area: fruit ratios decreased with increasing flower bud density in both cultivars. Average fruit fresh weight and fruit soluble solids decreased in both cultivars, and fruit ripening was delayed in `Misty' as leaf area: fruit ratios decreased. This study indicates that because of the inverse relationship between flower bud density and canopy establishment, decreasing the density of flower buds in SHB will increase fruit size and quality and hasten ripening.

Free access

Two southern highbush blueberry cultivars, `Sharpblue' and `Misty', were used to investigate the influence of varying flower bud density and fruit load on vegetative development, whole-plant canopy CO2 exchange rate (CER), and leaf CER. Plants were grown in pots and flower buds were removed so that initial flower bud density (fl ower bud number/total cane length) on a whole-plant basis ranged from 0.05–0.35 flower buds/cm. Vegetative budbreak number, leaf area, and leaf area: fruit ratio decreased with increasing flower bud density. In `Sharpblue', whole-plant canopy CER measured at fruit ripening decreased with increasing flower and fruit load and decreasing leaf area:fruit ratio, while leaf CER increased with increasing fruit load and decreasing leaf area:fruit ratio. In `Misty', whole-plant canopy CER measured 4 weeks after full bloom decreased with increasing flower and fruit load, but whole-plant canopy and leaf CER at fruit ripening were similar among the different fruit loads. Average fruit fresh and dry weights increased and the fruit development period decreased with increased leaf area:fruit ratio in both cultivars. These data suggest that carbohydrate source limitations from reduced leaf area development and whole-plant canopy CER lead to decreased fruit fresh and dry weights and delayed ripening in some southern highbush blueberry cultivars.

Free access