A study on the effects of GA3 application on fruit yield and quality in the Viet Cuong persimmon cultivar (Diospyros kaki L.)

The results conducted from the GA 3 application on 12-year-old trees of Viet Cuong persimmon cultivar grown in Thai Nguyen province showed that GA 3 , when sprayed timely with suitable concentration helps to improve the fruit set rate and fruit yield remarkably. Spraying GA 3 with concentrations ranging from 20 to 60 ppm and applied at one of three stages: 10 days before flowering, full blooming and 15 days after the second spray (fully bloomed status) had a good impact on fruit setting and fruit yield.In which, GA 3 at 40 ppm concentration of 15 days after full bloom reports the best results, with 21.7% fruit set and 40.5 kg/tree produced.The times of GA 3 spray also positively affected these parameters, which means the fruit set rate and fruit yield increased together with the spray times.In which, spraying 40 ppm of GA 3 3 times gave the best results (24.7% fruit set, 288.3 fruits/tree, 156.8 g/fruit, and 45.2 kg/tree).It is also mentioned that spraying GA 3 had no effect on the fruit quality of the Viet Cuong persimmon cultivar.These findings can be applied to the establishment of persimmon cultivating technology in Thai Nguyen and similar ecological areas as well.