%0 Journal Article %A Alberto Miele %A Robert J. Weaver %A Johnny Johnson %T Effect of Potassium Gibberellate on Fruit-Set and Development of Thompson Seedless and Zinfandel Grapes %D 1978 %R 10.5344/ajev.1978.29.2.79 %J American Journal of Enology and Viticulture %P 79-82 %V 29 %N 2 %X KGA3 applied to Thompson Seedless grapes when the flowers ranged from 30 to 80% bloom tended to increase the percentage of abscised ovaries, most of which were 1 mm or less in width. The percentage of berries set was decreased by KGA3 at 25 ppm. Berry weight was increased by the KGA3 treatments, but cluster weight was decreased at 25 ppm. Percent looseness was also increased by KGA3 at 25 ppm.Application of KGA3 to Zinfandel grapes at pre-bloom caused a decrease in percentage of abscised ovaries, most 1 mm or less in width. There was a large increase in the percentage of ovaries that remained attached to the clusters, and a decrease in percentage of berries set. Weight per cluster and weight per berry both decreased. Elongation of clusters increased with higher concentrations of KGA3. Clusters dipped into KGA3 at 10, 25, and 50 ppm became straggly. The °Brix increased in fruits treated with KGA3 at 50 ppm. Total titratable acidity did not differ significantly among treatments.The frequency distributions for Thompson Seedless and Zinfandel berry sizes were maximum for the class interval 12.0 to 13.9 mm wide. %U https://www.ajevonline.org/content/ajev/29/2/79.full.pdf