Relationship between change in endogenous hormone content and occurrence of wizened bud in Chinese pear

A study was conducted to investigate the relationship between the change in endogenous hormone content and the occurrence of wizened bud in pear. The abnormal buds with wizened bud deformity and normal buds of Chinese pear 'Yuluxiangli' from Wexian (Hebei, China) and pears with normal bud formation from Taigu (Shanxi, China) were used as samples. ELISA was used to analyze the changes in bud endogenous hormone content at the stage of flower bud differentiation. The indole acetic acid (IAA) content in abnormal buds was higher than that in normal ones, at the wizened bud stage. The abscisic acid (ABA) content in normal buds was significantly higher than that in abnormal ones from mid-June to early August, whereas the gibberellic acidý (GA₃) content in normal buds was lower than that in abnormal ones. Contents of zeatin riboside (ZR) in normal buds from Weixian and Taigu orchards were lower than that in abnormal buds of the Weixian orchard from early June to mid-June (initial stage of flower bud differentiation). Ratios of ZR/IAA, ZR/GA₃, ABA/GA₃, ABA/IAA, ABA/ZR, ABA/(ZR+GA₃), ABA/(IAA+GA₃), and ABA/ (ZR+GA₃+IAA) in normal buds were significantly higher than those in abnormal buds from the pear orchard in Weixian, Hebei. It was concluded that the application of management practices can restrain vegetative growth, regulate metabolism of plant hormone, and create balance between the vegetative growth and reproductive growth, which can decrease the incidence of wizened bud.