The Use of Paclobutrazol on the Young Apple Trees
Cui Huaiyu and Huang Xiangan(Zhengzhou Fruit Research Institute CAAS,Henan,450004)Xin Baojun and ZhangQiuying;Yu Hongxian and LiuQuande(Agriculture and Animal Bureau,YuZhou,Henan Province)(Forestry Bureau,Fugou County ,Henan Province)
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.