Test of Paclobutrazol Applying in Chestnut Close Planting Garden

In order to achieve the objectives of short stem,small crown of high yield chestnut,paclobutrazol(PP333) of different concentrations were applied in tested chestnut close planting garden located in Eshan county of Yunnan province.The experimental results showed that PP333 of proper concentration could effectively inhibit the branch growth of chestnut trees.One hundred days after spraying PP333 of 1 000～1 500 mg/L,compared with the control,the growth of branch length decreased by 56.2 % to 65.9 %,the diameter of branch increased by 0.09 cm to 0.11 cm,the fruit setting percentage increased by 17.4 % to 22.2 %.High concentration of PP333 such as 2 000 mg/L caused chemical injury,the growth of new branch was inhibited,and the fruit setting percentage decreased.Low concentration of 500 mg/L,no significant inhibition effect was produced.