Effect of spraying NAA and GA3 on preharvest fruit drop and quality of A4 seedless Litchi

The effects of different growth regulator on preharves fruit-drop and fruit quality were studied, taken10-years-old A4 seedless Litchi trees as material. The results showed that 10~80 mg/L NAA and 10~80 mg/L GA3treatment could prevent litchi fruits to drop before harvest and improve fruit quality significantly. In differenttreatments, 40 mg/L NAA treatment could reduce preharvest fruit-drop rate and fruit titratable acidity (TA) content,as well as improve single fruit size and weight remarkably; 20 mg/L GA3 could also reduce preharvest fruit-drop rateand TA content of fruit flesh, and increase single fruit weight very well.