Efficiency of CPPU on Increasing Size and Quality of Longan Fruit cv. Daw

Abstract

The effects of CPPU (N-(2-chloro-pyridyl)-N’-phenylurea) on size and quality of longan fruit cv. Daw were carried out at farmer orchard in San Sai district, Chiang Mai. Randomized Complete Block Design with 5 blocks (trees) and 4 CPPU concentrations as 0 (distilled water – control), 10, 20 and 30 ppm were used. Five fruit clusters at 12 weeks after fruit set (aril developmental stage) with regular fruit size and about 40 fruits per cluster from each tree (block) were randomed and dipped in the CPPU solutions three times at weekly interval. The results revealed that CPPU concentration at 30 ppm gave the biggest fruit both in the parameter of fruit diameter and average fruit size. At this concentration also gave the highest average fruit weight and the total soluble solid (TSS) value. However, the concentrations of CPPU did not affect on total titrable acid (TA), peel thickening and peel color. Economically consideration found that CPPU concentration at 30 ppm could increase the gross income per tree from 741.23 Baht (for control) to be 1,166.76 Baht or as 57.41 % increasing.