Leaf Area Index for Flat Shape Trained Longan (Dimocarpus longan Lour.) Trees to Improve Fruit Quality and Yield

摘要

The using of leaf area index (LAI) in order to improve yield and fruit quality of longan was conducted in two experiments.The first experiment was performed in 6-year-old fiat shape.trained 'Daw' longan trees from September 2005 to July 2006. The treatments were a) defohation of old leaves at 20% of the whole tree,b) defoliation at 40%,c) defoliation at 60%,and d) no defoliation (control),with four single tree replicates,applied at 60 days after anthesis. After harvest,the results showed that the fruit yield of all the treatments gave no significant differences,but the defoliation treatments at 40 and 60% gave extra large fruit percentages of 50.65 and 50.94%,respectively,which were higher than the control trees (30.93%),and the 20% defoliation (33.90%).In addition,the LAI of the control trees and the 20% defoliation trees were 6.27 and 5.31, respectively,which were significantly higher than the 40 and 60% defoliation,3.49 and 2.47 respectively. In the second experiment LAI at 2 and 3 (by defoliation of old leaves) compared with control trees, LAI at about 7.This experiment used four flat shape 5-year-old 'Daw' longan tree replicates,conducted from August 2006 to February 2007. After harvest,the results showed that the yield,the seed size and weight,the pericarp weight and thickness, and the fruit total soluble solids gave no significant differences among the treatments. But the aril weight and the aril recovery percentages of the trees with LAI at 2 and 3 were significantly higher than the control trees.In addition,the fruit weight,the fruit size,and the aril thickness of the trees with LAI at 3 were significantly higher than the control trees,but showed no significant differences to the trees with LAI at 2.