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- Author or Editor: D. L. Cawthon x
Abstract
Succinic acid-2, 2-dimethylhydrazide (daminozide), at rates of 0, 1000, and 2000 ppm, was applied between first and peak bloom to 2 adjacent ‘Concord’ (Vitus labrusca L.) vineyards: a 9-year-old vineyard with a histoty of good fruit set and a 19-year-old vineyard with a history of poor fruit set. No significant yield increase was obtained in the young vineyard, but there was a tendency for lower soluble solids and poorer juice color due to daminozide. Yields were increased by 2.4 and 3.3 MT/ha by 1000 and 2000 ppm daminozide, respectively, in the older vineyard with no significant effect on juice quality. The one-year increase in yield of grapes in the older vineyard was accompanied by a reduction in vine size.
Abstract
‘Tifblue’ and ‘Delite’ rabbiteye blueberry (Vaccinium ashei Reade) plants were grown for 4 years with or without mulch, with cultivated or sodded row middles, and under various irrigation treatments [one drip emitter at the base of the plant, two drip emitters 46 cm on either side of the plant, or a 40° or 360° low-volume spray emitter (LVSE) placed midway between plants]. Plant establishment and growth were optimal with 360° LVSE. Differences between irrigation treatments were minimized with mulch. Mulch increased growth of drip-irrigated but not of LVSE-irrigated plants and increased the yield of two-emitter and 360° LVSE-irrigated plants but not of one-emitter or 40° LVSE-irrigated plants. Treatment effects on growth were more apparent in the early establishment phase than in the 4th year of growth and with ‘Tifblue’ than ‘Delite’. Frost damage on ‘Delite’ was reduced by mulch. Vegetative bud development in the spring and fruit maturity were usually delayed on plants grown between sodded alleys or with mulch. Leaf drop in the fall was also delayed by mulch.
Abstract
A study was designed to examine the effects of production systems (i.e., standard bed, wide bed, and black plastic bed), a high and low plant population, and 3 harvest dates on the machine-harvested yield and quality of 2 strawberry (Fragaria × ananassa Duch.) clones. ‘Cardinal’ produced higher yields than A-5344, but had poorer quality. The wide-bed production system produced higher yields than the other production systems and had no adverse effects on quality. ‘Cardinal’ had optimum yield when produced under a low plant population, while A-5344 had optimum yield under a high plant population. Fruit quality was maintained throughout the 5- to 7-day harvest season each year.
Abstract
A 4-year study was conducted on ‘Niagara’ grapes (Vitis labrusca L.) to examine the effects of 3 pruning severities (based on nodes retained), 3 levels of nodes/bearing unit (3, 6, and 9), 2 training systems [Geneva Double Curtain (GDC) and Bilateral Cordon (BC)], and 2 canopy management treatments (shoots positioned and shoots not positioned) on yield and fruit quality. Leaving heavy fruit loads suppressed yields in the 4th and final year of this study as a result of reduced node fruitfulness. The 3 node spurs were not as productive as the 6 and 9 node canes. GDC training produced higher yields than BC training in the 3 high yielding years of the study while maintaining vine vigor. Shoot positioning was more beneficial in increasing yields on the BC training system than on the GDC training system, because of the crowded conditions of the canes on the BC system. The effects of these variables on fruit quality were small, but the heavy fruit loads did result in fruit with a reduced percentage of soluble solids and pH, increased acidity and light color (increased CDM ‘L’ values). Shoot positioning reduced fruit pH, slightly in-creased acidity, and produced darker color (decreased CDM ‘L’ values). Under Arkansas growing conditions, if harvest is delayed beyond 14% soluble solids, it is possible that unacceptable fruit pH and acidity levels will exist.
Abstract
Mechanically harvested fruits of A-5344 and ‘Earlibelle’ strawberry (Fragaria × ananassa Duch.) were stored at 24°C for 72 and 120 hours in atmospheres containing acetaldehyde (Aa) with and without prior dipping in 0 to 1.5% acetaldehyde solutions. Aa atmospheres and a combination of atmospheres and dips were most effective in maintaining visual color, freedom from browning, and product acceptability of machine harvested strawberries for processing. Fruit stored in atmospheres containing Aa vapor increased in acidity by 72 hours.
Abstract
Multiple preharvest applications of CaCl2 at 1000, 2000, or 4000 ppm (actual Ca) had little effect on fruit firmness of blackberry (Rubus sp.) at harvest. After a 24 hour holding, fruit from the first harvest was firmer if treated with Ca. Preharvest Ca treatments reduced soluble solids accumulation in fruit and 4000 ppm caused foliar damage. Ca had little effect on acidity or color at harvest, but reduced the rate of ripening during postharvest holding.
Abstract
Succinic acid-2,2-dimethylhydrazide (daminozide) applied to ‘Raven’ blackberries at 4000 ppm and to ‘Raven’ and ‘Brazos’ at 2000 ppm between full bloom and first color development and at 2000 ppm in a multiple application applied at full bloom, 2 weeks, and 3 weeks after full bloom resulted in reduced berry size and yield with no beneficial effects on fruit quality. (2-Chloroethyl) phosphonic acid (ethephon) applied to the same cultivare at 1000 ppm 4 days prior to the first harvest increased the amount of fruit mechanically harvested on the first harvest. Ethephon treatment improved color but resulted in mechanically harvested fruit having lower soluble solids and acidity.
Abstract
Yields on ‘Concord’ grape (Vitis labrusca L.) increased as pruning severity was decreased until the 6th and last year of this study, at which time the yields tended to equalize between the 30 + 10, 50 + 10, and 70 + 10 pruning treatments. By the last year, vines pruned to the 70 + 10 level produced fruit of unacceptable quality. When the 3-node spurs were shoot-positioned, their productivity was comparable to buds on the 6- and 9-node canes, indicating the need for exposure to sunlight. The length of the bearing unit has little or no effect on fruit quality attributes. In general, shoot positioning increased yield, node productivity, the percentage of soluble solids, and lowered vine size throughout the study. Geneva Double Curtain (GDC) trained vines produced more fruit than the bilateral cordon (BC) trained vines. Fruit from GDC trained vines had a reduced percentage of soluble solids in 2 of the last 3 years, and tended to have a low pH. The most productive vines producing fruit of acceptable quality for the 6-year mean were the GDC trained, 50 + 10 pruned to 6-node bearing units, and shoot positioned.
Abstract
Under commercial conditions at harvest, mechanically harvested blackberries (Rubus sp.) had raw and processed quality comparable to hand-picked fruits regardless of berry temperature. However, during storage, berries machine-harvested at high temperature (36°C) deteriorated more rapidly than hand-picked berries at the same temperature. Storage of machine-harvested fruit in 20% and 40% CO2 at 20° for up to 48 hours maintained raw and processed quality. When mold counts were not excessive, the use of flavoring ingredients in the processed product resulted in acceptable products despite unacceptable raw product quality from some treatments. Use of high CO2 storage atmospheres with fruit held at 20° partially offset the need for refrigeration to reduce postharvest quality loss.
Abstract
The development of a mechanical harvester for erect blackberries is traced from its inception to commercialization. The harvesting and production system tested in this study required productive, erect cultivars that are mechanically pruned to form continuous hedgerows. An acceptable processed product is obtained from the system.