Effect of pruning rate on the tree growth, fruiting and root growth of open-center shaped pear.

The young trees of open-center shaped Housui pear were used as the material to study the effect of different pruning rate(light,heavy and no) on the pear tree growth,fruiting and root growth.The results showed that light pruning increased tree vigor and heavy pruning and no pruning went against the tree growth.The average weight of the fruits with light pruning was higher than no pruning.The no-pruning tees got small fruit and low-yield,on the other hand,the light pruning trees got large and uniform fruit,high-yield.The order of fruit yield was light pruningheavy pruningno-pruning.The root system of different pruning rate mainly distributed in the 0~60 cm vertical depth and 150~300 cm horizontal width in soil layer.The absorption root of pear those mainly distributed in the 20~50 cm vertical depth and 150~200 cm horizontal width in soil layer.The root system with light pruning distributed more deeply and widely,that with no-pruning distributed deeply,but not widely,and that with heavy pruning was in the middle.In the hilly areas,light and extending pruning should be the main choice of open-center shaped pear trees.