Effect of regulated deficit irrigation at flowering stage on growth and fruit setting of loquat

In order to study the effect of regulated deficit irrigation at flowering stage on loquat growth and fruit yield，the optimal regulated deficit irrigation system was put forward. 14-15 years’ old‘ Zaozhong6hao’ loquat trees in field were used as materials，and local drip irrigation method was applied. The regulated deficit irrigation system was carried out by giving different gradient irrigation quantity and different irrigation period at flowering stage. The trees without irrigation were used as control. The growth potential of loquat tree in fruit setting period and yield indexes at fruit maturing stage were investigated. Results showed that in the treatment of 1 time irrigation per 15 d at flowering stage，with the increase of irrigation quantity，the defoliation rate of branch in fruit setting period obviously decreased，while the relative content of chlorophyll in leaves increased obviously；and the leaf survival rate in fruit maturing period showed an obvious increasing trend，while the wrinkle fruit rate decreased obviously， and the average single fruit weight increased. Consideration of water saving，when irrigating 45 kg water per tree every time，less defoliation rate and higher chlorophyll content of leaves were detected during fruit setting period than other treatments，meanwhile less wrinkle fruit rate and larger single fruit were investigated in fruit maturing period；It showed that 45 kg water per tree was the best irrigation amount. When irrigating 45 kg water per tree every time，the 8d irrigation interval was the best treatment with less defoliation rate than contorl；while the longer the irrigation interval， the higher defoliation rate in fruit setting period. This study suggested that the regulated deficit irrigation at flowering stage enhanced the growth potential of loquat tree in fruit setting period and increased fruit yield at fruit maturing stage， and the optimal regulated deficit irrigation system was irrigating once with 45 kg water per tree every 8 days.