1a. Objectives (from AD-416)
Improve the quality and storage life of table grapes by the application of sprays directed into grape clusters in vineyards before harvest.
1b. Approach (from AD-416)
In repeated cluster-directed applications between fruit set and harvest, apply calcium salts, hormonal treatments, reduced-risk fungicides, biological control agents, and other compounds before harvest, then determine their influence postharvest quality (color, texture, maturity, size) and decay (natural incidence of diseases, after artificial inoculation) of table grapes.
3. Progress Report
This agreement was established in support of Objective 1 of the in-house project, the goal being to develop integrated and commercially feasible pre-harvest practices and treatments to improve quality and extend the shelf and shipping life of fresh fruit (primarily citrus fruit and table grapes). Several vineyards were selected and a variety of growth regulators, elicitors of pathogen defense reactions, and mineral nutrients were applied to developing grape clusters of nine common table grape cultivars to determine their impact on berry quality. Berry color, size, firmness, sugar content, and incidence of decay pathogens measurements were made. Results indicate that, with many cultivars, decreases in decay and substantial increases in firmness, sugar content, and/or red color were among the effects observed after applications of potassium salts directly into clusters after flowering.