多效唑在苹果幼树上应用

红星、红富士苹果幼树施用多效唑后，对抑制新梢生长、调节枝条组成、促进花芽形成、提高坐果率、增加幼树产量、控制树冠增长均有明显效果，效果大小与施用方法、时期、药剂浓度和剂量、品种有关，土施比叶喷效果好。土施以３月或９月施入为宜，叶喷的最佳时期为５月上旬。土施的适宜剂量为０．５一１．０ｇ·ｍ~(-２)，叶喷最适浓度为１５００一２０００ｍｇ·１~(-１)。红星比红富士对药剂反应敏感。多效唑施后的持效期土施比叶喷的长，并随着剂量和浓度的增加而延长。土施０．５一１．０ｇ·ｍ~(-２)持效期为２一３年，叶喷１５００一２０００ｍｇ·１~(-１)的持效期仅为１年。

The Use of Paclobutrazol on the Young Apple Trees

Paclobutrazol application gnificantly inhibit shoot extension,elevated the spur percentage,promotedthe flower ormation and fruit set,and finally increased the yield of young apple trees.The intensity of thoseeffect shown above was closely related to the method of application,the timing of treatment and the cultivars.The Red Delicious apple was more sensitive than Fujiapple. The result obtained from soil application was su-perior to that from foliar spray. The 0.5一1.0mg a.i.·m￣(-2) and 1500一2000mg·1￣(-1)were recommanded forsoil application and foliar spray,respectively.The timing recommanded for soil application was March and /orSeptember in previous year,and for foliar spray the first ten days of May.The effective period was longerwhen paclobutrazol was used as a soil drunch than was used as a foliar spray. The former may last 2一3yearswhen 0.5一1.0mg a.i.·m￣(-2) was adapted,but the later was not longer than one growing season. The morethe dosage and/or the concentration used,the longer the effective period.