Determination of Stem Cutting Season for Vigor Control of Japanese Pear in ‘Tree Joint’ Training Method

서지정보

· 발행기관 : 한국원예학회
· 수록지 정보 : Horticulture, Environment, and Biotechnology / 50권 / 2호 / 104 ~ 108페이지
· 저자명 : Tatsuya Seki, Ichiro Kitao, Kenichiro Shibata, Hiroshi Gemma

초록

In March 1997, we developed a new training method, called ‘tree joint training system’, for Japanese pear (Pyrus pyrifolia) in order to realize early maturing orchard and labor saving management. This method is based on grafting, joining many trees and creating one linearly congregated tree. In this system, however, trees become more vigorous than an individual tree. One effective method of vigor control is to cut off some of the main stems in the congregated trees. We have investigated the appropriate season for cutting off the main stem by monitoring physiological parameters and sap flow in the joined trees. From May to October in 2007, the effects of cutting off the stem of central tree of three ‘Kosui’ joined trees on photosynthesis, stomatal conductance, and transpiration rate were investigated. When cutting was done in May and July, photosynthesis, stomatal conductance, and transpiration rate at the central tree immediately showed drastic reduction, and leaves of the central tree were wilted, while no clear effect was observed in the top and bottom trees, suggesting that short term effect on production and water status by cutting off stem of the central one occurs only in the central tree, not in the adjacent trees. In the cutting treatment of September and October, there was very little reduction in transpiration rate in all the joined trees, suggesting that there might be very little short term effect. Flow rate of joined trees in late October after cutting stem off was investigated. Immediately after cutting, flow rate of the central tree rapidly reduced from 32 to 0 g･h-1 in 1 h, but no clear change was seen in the top and bottom trees. There was no visible change in leaves of the pear trees. Thus, soon after joining, in the spring and summer, cutting off treatment would sharply affect the transpiration and water status of the tree; however in the late fall, short term effect was limited because leaf activity was relatively low, though the sap flow was affected. In conclusion, season of cutting off the stem for vigor control in the end of September through the end of October might be appropriate for avoiding short term stresses.

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