Abstract:
This investigation was carried out during three seasons i.e. 2010, 2011 and 2012 on Flame Seedless grapevines grown in sandy soil in El-Karnak vineyard for table grapes production, Luxor governorate, Egypt. Ten combined treatments of GA3, urea and active dry yeast spraying at various stage of berry development were evaluated. The experimental vines were arranged in a complete randomized design with three replications per treatment, two vines each. From the results of this investigation it could be concluded that spraying with GA3 seven times, once at pre-bloom (5 ppm), thrice at full-bloom (2.5, 5 and 7.5 ppm) and other thrice when the berry at (6 mm) pea stage (30, 30 and 20 ppm). As well as, combined spraying GA3 four times once at pre-bloom and thrice at full-bloom plus 0.4% active dry yeast when the berry at pea stage to obtain heavy and less compact cluster and hasten the ripening with fairly good Flame Seedless berries quality. In addition, it could be used urea and yeast instead of GA3 in grape production to overcome the adverse GA3 effects especially for colored cultivars.