THE EFFECTS OF GA3, CPPU AND ABA APPLICATIONS ON THE QUALITY OF KYOHO (VITIS VINIFERA L. X LABRUSCA L.) GRAPE

Abstract

This study was carried out to investigate the effects of GA3, CPPU (N-(2-chloro-pyridyl)-N'-phenylurea), and ABA on the fruit quality of ‘Kyoho’ (Vitis vinifera L. x V. labrusca L.) grape. The clusters on 7-year-old ‘Kyoho’ grapevines were soaked into 25 mg/L GA3, 10 mg/L CPPU, and 1000 mg/L ABA solutions, alone or in combination. GA3 and CPPU were applied 10 days after full bloom and ABA at veraison. GA3 treatment increased cluster length, weight, and berry weight. CPPU treatment increased cluster length, diameter, weight and berry weight. These effects were risen by the combined treatment of GA3 and CPPU more than GA3 or CPPU alone. Total soluble solids and titratable acidity were not significantly different among all treatments. Anthocyanin content in berry skin was reduced by treatments of GA3 and CPPU, suggesting their inhibitory role for anthocyanin synthesis. ABA treatment increased significantly anthocyanin content of grape treated with GA3 and CPPU. So, it was concluded that the combined treatment of GA3, CPPU, and ABA was effective for fruit enlargement and coloration. GA3 and CPPU treatments did not affect glucose and fructose contents, but ABA increased it a little.