Effects of Cutting Back Pruning on Sprouting and Fruit Set in Japanese Pepper (Zanthoxylum piperitum (L.) DC. f. inerme Makino) Trees

Abstract

Pruning of Budousanshou (Zanthoxylum piperitum (L.) DC. f. inerme Makino) trees was investigated to determine whether the pruning degree influences sprouting and fruit set. First, the mother branches were divided into three groups by length, and then the four degrees of pruning were set up, i.e. no pruning, cutting back 1/3, cutting back 1/2, and cutting back 2/3 for each mother branch group. The sprouting rate, spike-bearing shoot rate, flower number and berry number in the fruit cluster were compared next spring. As a result, there was a greater tendency toward higher many flower numbers, berry numbers in the fruit cluster and berry numbers per mother branch after cutting back 1/3. These numbers tended to be higher than those in the other pruning groups for the medium mother branch length. The sprouting rate increased when trees were pruned by cutting back 2/3 and the spike-bearing shoot rate tended to become higher after cutting back 1/2 or 2/3.