Effects of renewal pruning on shoot development and crown structure of the aging Fuji apple tree

This paper is concerned on the effects of renewal pruning on shoot growth and crown structure of the aging Fuji apple tree.The long-branch pruning was used as control.The measured parameters were included shoot growth dynamics,crown structure change,fruit yields and quality.The results showed that both newly-developed shoots and lateral shoots of bearing part of different treatments were of character with a single growth peak.The length and diameter of the newly-developed shoots due to pruning were increased by 63.92% and 20.93% respectively,whereas by 51.14% and 9.76% respectively for the lateral shoots of bearing part.In same crown size,the numbers of water branch,long and medium branch and foliage branch were increased by 132.93%,82.59%,54.47% and 76.84% respectively,but short branch,leafage branch and fruit branch by 28.84%,31.57% and 22.64% respectively.However,the canopy of the pruned tree was reduced by 14.53%.Total number of branches was also reduced by 27.82%.Leaf area index,average foliar obliquity and extinction coefficient were increased by 9.64%、153.22% and 2.97% respectively.The canopy openness was reduced by 13.15%.The fruit weight and fruit yields were increased by 23.61% and 30.02% respectively.The renewal pruning had no significant effect on fruit eating quality.