| The effects of two growth regulators on the growth and development of 'Seyval', a wine grape cultivar, and 'Himrod', a seedless table grape cultivar, were investigated. In the first experiment, cluster-thinned and non-thinned vines of 'Seyval' were sprayed with 0, 20, or 40 mg/L gibberellic acid (GA;Cluster thinning had little effect on bunch and juice characteristics of 'Seyval' the first year, but by the second year, thinning resulted in heavier clusters, more berries per cluster, higher percent soluble solids, and lower acidity. Non-thinned vines tended to show a decrease in pruning weight.;Gibberellic acid sprays resulted in lower bunch weight and number of berries per cluster, heavier berries, and increased rachis length at both application times. The decrease in number of berries per cluster and increase in berry weight was greater with late application, while the increase in rachis length was greater with early application. Interactions between early and late sprays were significant for bunch weight and berry number. Incidence of bunch rot tended to be reduced by GA;Cluster weight, number of berries per cluster, and individual berry weight of 'Himrod' increased linearly with increasing Promalin concentration. There was a negative linear relationship between percent soluble solids and Promalin concentration, apparently as a result of the increased crop load on the treated vines. Rachis length, number of shot berries per cluster, and titratable acidity were not significantly affected by Promalin concentration. |
