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

Open 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

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

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.

Open Access

The udiA gene encoding the enzyme β -glucuronidase (GUS) appears promising as a genetic marker for early confirmation of successful plant cell transformation. Two strains of Agrobacterium rhizogenes and eight strains of A. tumefaciens were selected as hosts to carry a binary plasmid (pBI121) containing the marker gene encoding the GUS marker that is controlled by the CaMV35S promoter. Presence of plasmid pBI121 in the bacteria was confirmed by resistance to kanamycin, plasmid re-isolation, and restriction enzyme analysis. When the GUS enzyme was expressed in transformed plant cells, reaction with the histochemical substrate 5-bromo-4-chloro-3-indolylglucuronide (X-gluc) lead to blue pigment development. Expression of GUS in viable bacteria that had not been eliminated from transformed tissue caused problems with the early transformation detection in radish, peach, and apple stem sections by also producing a positive X-gluc color reaction. Putative transformation of apple xylem parenchyma callus was accomplished, as judged by resistance to kanamycin, opine analysis, GUS marker gene expression, and presence of the APH(3')11 enzyme. In this system, elimination of bacterial contamination was accomplished during multiple culture transfers on selective media. To be more useful as a marker, the GUS gene should be coupled with a promoter that will not be expressed by Agrobacterium. Parenchyma callus may serve as a primary screen to provide an efficient way of determining the ideal strain for transformation of deciduous tree fruit genera. In our studies, strain A281 consistently proved to be a vector superior to others tested.

Free 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

A muscadine grape (Vitis rotundifolia) planting was established in 1996 at the Southwest Research and Extension Center in Hope, Ark., to provide information on the performance of muscadine grape cultivars in a region where cold hardiness is not a major limitation. This research evaluated harvest parameters, fruit and juice quality, and nutraceutical potential of selected muscadine cultivars grown in southwestern Arkansas. The cultivars evaluated were `Black Beauty', `Carlos', `Cowart', `Doreen', `Early Fry', `Fry', `Granny Val', `Ison', `Jumbo', `Late Fry', NC67A015-17, NC67A015-26, `Nesbitt', `Scarlett', `Southern Home', `Sterling', `Sugargate', `Summit', `Supreme', and `Tara'. Muscadine cultivars differed in productivity and fruit quality. In 2002 and 2003, juice was produced from `Carlos', `Granny Val', `Ison', `Nesbitt', `Southern Home', `Summit', and `Supreme' grapes. `Black Beauty' was also produced into juice in 2003. In 2002, `Nesbitt' grapes had the highest juice yield, 520 L·t–1 (124.6 gal/ton). `Ison' and `Supreme' juice had the highest soluble solids level. In 2003, `Granny Val' grapes had the highest juice yield, 551 L·t –1 (132.0 gal/ton). `Southern Home' juice had the highest soluble solids. The press materials of muscadine grapes were a potential source of high levels of nutraceutical compounds. Dried seeds had the highest total phenolic and oxygen radical absorbance capacity (ORAC) levels followed by the dried skins, the grapes, and then the juice. The skins of the black cultivars had the highest total anthocyanins level. `Supreme' seeds had the highest total phenolic and ORAC levels while `Ison' skins had the highest total anthocyanin levels. Based on yield, harvest, and juice quality, cultivars recommended to growers in southwestern Arkansas and other areas with a similar climate include `Black Beauty', `Carlos', `Fry', `Granny Val', `Nesbitt', `Southern Home', `Summit', and `Supreme'.

Full access

Abstract

Two cultivars of strawberries originally harvested for fresh market were held under 5 postharvest storage treatments and then dipped in one of 4 chemical treatments. The berries were sliced or left whole, dipped, and then processed by freezing or thermal processing. The processed product from ‘Cardinal’ was superior to that from ‘Sunrise’ in this study, regardless of the holding or dip treatment. ‘Cardinal’ berries could be utilized for processing initially and after storage for 4 days at 4°C and after 2 days at 21°; however, ‘Sunrise’ was acceptable only initially and up to 4 days at 4°. Dipping berries for 1 min in a 0.5% calcium lactate solution or a 0.5% Ca lactate plus 1% citric acid solution improved berry firmness and character. The Ca dips were more effective in firming sliced berries than in firming whole berries. The Howard mold count of the berries became a major limiting factor for many of the postharvest storage treatments.

Open Access