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  • Author or Editor: J. L. Morris x
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Abstract

Naphthaleneacetic acid (NAA) was applied to 10-year-old ‘Concord’ grapevine trunks at 0, 2, 4, and 8% concentrations. Best control of shoots on trunks was obtained with the 4 and 8% concentrations with no visual foliar injury or detrimental effects on yield, vine size, or fruit quality. One application of NAA at 8% reduced the number of trunk shoots for 3 years, but 100% control was obtained only in the year of application.

Open Access

Abstract

Preharvest field temperatures can influence composition and quality of vegetables at harvest as well as their postharvest responses. Temperatures which injure or weaken the tissues prior to harvest will reduce storage life and increase susceptibility to decay.

Freezing temperatures in the field can greatly reduce storage life. In addition, many vegetables suffer injury when exposed for certain periods of time to temperatures above freezing but below about 10°C. This injury, termed chilling injury, is most often associated with vegetables of tropical and subtropical origin; however, some temperate-zone vegetables can be injured by low, but non-freezing, temperatures.

High field temperatures can result in physiological disorders and increased deterioration. High field temperatures can induce injury visible at harvest, such as sunburn or sunscald; however, serious problems can also occur during storage and handling following injury which was not visible at harvest.

Open Access

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.

Open Access

Abstract

Numerical rating scales and their descriptive equivalents for firmness, visual quality, decay, butt discoloration, wilting, and other defects of lettuce (Lactuca sativa L.) are described. Also presented are scoring systems for brown stain, russet spotting, and rusty-brown discoloration of crisphead lettuce that consider severity of lesions, proportion of leaf affected and number of leaves affected in a head.

Open Access

We compared transpiration estimates of three common desert landscape tree species using stem-flow gauges and lysimetry. Argentine mesquite (Prosopis alba Grisebach), desert willow [Chilopsis linearis (cav.) Sweet var. linearis], and southern live oak (Quercus virginiana Mill., seedling selection) were subjected to three irrigation regimes. Leaching fractions of +0.25, 0.00, and -0.25 were imposed for 2 years. During the summer of the second year, we conducted a comparative transpiration study. Trees growing in 190-liter plastic containers had a highly linear correlation (r = 0.98, P = 0.001) between transpiration estimated by stem-flow gauges and lysimetry. An average 18% error was measured between paired data (total runs of 14 to 72.5 hours) of stem-flow gauge and lysimetry transpiration estimates. However, a lower error was correlated significantly with longer run times (r = -0.37, P = 0.05). Based on field measurements taken in this experiment, run times would have to be >68 hours to maintain an associated error below 10%. Higher cumulative transpiration also was associated with longer run times (r = 0.80, P = 0.001). These results suggest that the stem-flow gauge can be used to estimate transpiration accurately to schedule irrigation for woody ornamental trees in an arid environment, provided that irrigation predictions are not based on short-term stem-flow gauge estimates (<68 hours).

Free access

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.

Open Access

Abstract

A completely mechanized system for production, harvesting and handling strawberries (Fragaria × anassa Duch.) for processing is described. Pre-harvest cultural factors, including bed preparation, plant population, harvest date and clonal evaluation and adaptability to mechanical harvesting, were studied for 4 years. ‘Cardinal’, ‘Earlibelle’, and Arkansas breeding line A-5344 were well suited for once-over mechanical harvesting under Arkansas conditions considering yield, quality, and organoleptic evaluation. Plant population densities in the matted row system used in this study generally had little effect on yield or quality, unless a clone was of low vigor and poor runner plant producer. As harvest date was delayed, quality and useable yield often decreased. However, a minimum of a 6 day harvest period for mechanical harvesting existed for the cultivars tested. The results of this study indicate that once-over mechanical harvesting of strawberries is feasible when the proper cultivar is grown on properly shaped beds with good cultural practices and adequate postharvest handling procedures.

Open Access

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.

Open Access

Staminate and pistillate flower maturity of 80 cultivars of young (<15 years old) pecan [Carya illinoinensis (Wangenh.) K. Koch] trees are presented. These patterns show that pollination and receptivity windows within the flowering season can be divided into very early, early, mid, late, and very late season protandrous (Type I) and protogynous (Type II) types. This system therefore provides a seasonally based 30-class Type I and Type II alternative to the standard two-class Type I and Type II system, thus offering enhanced resolution of flowering intervals and an improved means of selecting cultivars to ensure cross-pollination of yard and orchard trees. Scott-Knott cluster analysis of budbreak, nut ripening date, and date of autumn leaf drop segregated cultivars into one of several categories.

Free access

Abstract

Several Arkansas commercial grape growers operating tractor-mounted, low-boom vineyard spray rigs were monitored for potential dermal, respiratory, and internal exposure to paraquat (1-1′-dimethyl-4,4′-bipyridinium ion) during the 1980 and 1981 growing seasons. Workers followed their usual mixing and spraying routines with as little influence as possible from the test. Analyses by colorimetric methods revealed very low levels of paraquat exposure. Greatest dermal exposure levels averaging 0.015 mg paraquat/kg body weight were detected on persons operating the spray rigs. Respiratory exposure was minimal and there was no paraquat detected in any of the urine samples collected from each worker. Those persons receiving the highest levels of paraquat exposure had measurements which were well below those found to be toxic to laboratory animals. Hazards from using this material by this method of application should be low when used in accordance to label directions and precautions.

Open Access