Effect of some viticulture practices on fruit quality at harvest and storability of Thompson seedless grape [electronic resource].

Includes references.

Grape is one of the most important Horticulture crops in Egypt. This investigation was carried out during two successive seasons (2004 and 2005) at Hort. Res. lnst, Fruit Handling department, Gizza. The vines received one of the six following treatments: untreated vines (control), spraying with Dormex + Gibberellic acid (GA3) + thinning + girdling, spraying with Dormex + GA3 +thinning, spraying with GA3 + thinning + girdling, spraying with Dormex + GA3+ girdling, spraying with Dormex + thinning + girdling. At maturity stage bunches were harvested and packaged in a cardboard boxes (2.5 kg) lined with . perforated polyethylene bags and stored up to 28 days at 0°c or 5°c and 90:95 % RH. In the second part of this study, grape bunches (without any preharvest treatment) were harvested and sorted and packaged at the farm as following: in a small cardboard box (2.5kg), in a big cardboard box (7 kg), in a small plastic box (10 kg) with one layer of bunches, in a big plastic box (20 kg) two layers of bunches, in a big plastic box (25:30 kg full capacity) and stored up to 35 days at 00c 90: 95% % RH. Physical and chemical properties of grapes were estimated at harvest and at 7 day intervals during storage. All the studied combinations of these viticulture practices (spraying with Dormex, Gibberellic acid, thinning, girdling) significantly increased bunch weight and length, berry weight and size, berry contents of total soluble solids and decreased total acidity compared with untreated vines. Also, all these studied combinations significantly enhanced maturity stage of grape especially vines treated with Dormex, thinning and girdling which had the earliest grape maturation followed by vines treated with Dormex, GA3 and girdling and vines treated with Dormex, GA3, thinning and girdling, while untreated vines has had tl1e latest grape maturation by one weak latter. All viticulture practices under this investigation significantly decreased weight loss, decay, shatter and total spoilage incidence of grapes during storage. Also significantly decreased the softening rate of grape berries and the deterioration rate of grape bunches general appearance during storage compared with untreated vines, but had no obvious effect on the changes of total soluble solids and total acidity during storage. Low storage temperature (0°c) significantly reduced weight loss, decay, shatter and total spoilage incidence of grapes during storage. Moreover it reduced the softening rate of grape berries significantly during storage but bad no effect on general bunch appearance. Small and big carton boxes and small plastic box significantly reduced weight loss, decay, shatter, total spoilage incidence, berry softening rate and deterioration rate of bunch general appearance in stored grapes compared with other packaging. While, packaging type bad no effect on total soluble solids and total acidity contents of grapes during storage.

Summary in Arabic.

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