Effect of GA₃ and NAA on yield and quality of Java rambutan (Nephelium lappaceum L.) in Ben Tre and Tien Giang provinces of Vietnam

The present study aimed to evaluate the effect of GA₃ and NAA as foliar spraying on yield and quality of ten-year-old trees Java rambutan (Nephelium lappaceum L.). The experiment was carried out at Ben Tre and Tien Giang provinces, southern Vietnam which was arranged by randomized complete block design (RCBD) with four replications, and five treatments including 20 ppm NAA; 30 ppm GA₃; 20 ppm NAA + 30 ppm GA₃; 500 ppm Thien Nong (2% α NDASH NAA, 0.5% β NDASH NAA and 0.1% GA₃) and control. The treatments were sprayed at 4, 6, 8^th week after fruit set, respectively. The results showed that spraying 20 ppm NAA; 30 ppm GA₃; 20 ppm NAA + 30 ppm GA₃; 500 ppm Thien Nong reduced the ratio of fruit drop when compared to control. However, spraying 30 ppm GA₃; 20 ppm NAA + 30 ppm GA₃; 500 ppm Thien Nong increased firm thickness, total soluble solids (TSS) and yield when compared to spraying 20 ppm NAA and control.