EFFECTS OF KT-30 AND GA3 ON THE FRUIT-SET AND THE FRUIT-GROWTH OF PERSIMMON CVS SAIJO AND HIRATANENASHI

Effect of N-2-chloro-4-pyridyl-N'-phenylurea (Exp-code-KT-30) on the fruit set and the growth of Japanese persimmon cvs. Saijo and Hiratanenashi was investigated. 1. Applications of 10 to 20 ppm of KT-30 to flowers or to young fruitlets 10 days after full bloom significantly increased fruit set. 2. Treatment of immature fruits 10 days after full bloom promoted the growth of fruits moreso in length than in diameter. The effect of KT-30 on fruit enlargement was significant in cv. Hiratanenashi, but insignificant in pollinated fruit of cv. Saijo. In cv. Hiratanenashi, the fruit weight at harvest was increased significantly by 10 to 20 ppm KT-30 as compared to the control. 3. Treatment with KT-30 from anthesis to 20 days after full bloom delayed color development. Moreover, the later the time of application and the higher the dosage, the more effective was the treatment in delaying fruit color development. However, if the harvest time was delayed, the treated fruit eventually became highly colored and contained high soluble solids. 4. In conclusion, treatment of persimmon with 10 ppm KT-30 is a practical procedure for increasing fruit set and size in cvs. Saijo and Hiratanenashi.