The time of gibberellic acid application in the non-bearing year (OFF year) makes the different responses on seedless barberry plants in it (OFF year) and next year (ON year).
Objective: The present research was conducted to evaluate the effects of gibberellin sprays applied at different times on barberry plants.
The experiment was performed in three consecutive years (2016 to 2018) in Amirabad, Birjand, Iran. The treatments included: 1) Gibberellic acid (GA3 at 200 ppm), and 2) control (0 ppm), applied six times as foliar spraying on non-bearing trees, between April and September. The foliar sprays and measuring of vegetative traits were done on non-bearing trees in 2016 and 2017. Reproductive traits evaluated on bearing trees in 2017 and 2018.
Leaf number, width and length and internode length of current barberry shoots increased significantly. GA3 application significantly decreased by flower and fruit number, TSS/TA and anthocyanin content of fruit juice. Data showed that September might be a very important time for flower induction and differentiation. GA3 application increased the carbohydrate and phenol content of leaves and shoots.
Conclusion: It can be concluded that spraying gibberellic acid influences all physiological and reproductive traits of barberry plants.
Effects of Gibberellic Acid on Total Carbohydrate of Shoots, Vegetative Growth and Flower Production in Barberry Plants