拉枝对不同品种幼龄梨树生长结果的影响

对幼龄梨树拉枝，可使幼树树冠扩大，叶幕建成加速，长枝增多，长度缩短，果树比例增大。拉枝后总叶面积增大，树冠内膛光照减少，单位叶面积光合速率下降。拉枝处理增加各品种花序和座果量。品种间对拉枝反应有显著差异。花序量的增加以花芽易形成的黄花品种最为明显，树势强、枝条直立的４号效果较差；座果量的增加以花芽较难形成、生长势一般的７号和１７号最为显著，花芽易形成的黄花则不明显。拉枝促花的效应，多数品种表现在拉

Branch Drawing Influence on Growth and Fruit Setting for Young Tree of Pear Varieties.

For young tree of pear, branch drawing helps tree crown to expand,leaf curtain forming to speed up, long branch number to grow, branch lengthto reduce, and ratio of fruit and branch to increase. After branch drawing,cultivated varieties increase in general leaf area, decrease in light intensityinside tree crown and photosynthesis intensity, and increase in inflorescenceand fruit setting.Cultivated varieties differ greatly in branch drawing reac-tion. Yellow flower varieties,in inflorescence, are the most remarkable, butNo. 4 that is strong and erect branch is bad;in number of fruit setting, No.7 and No. 17 that are difficult in flower bud forming are the most remarka-ble, but yelower flower varieties that are easily in flower bud forming are bed. Major cultivated varieties have effect in flowering in the first year after branch drawing, with effectiveness for a given period of time.