Mehdi Khayyat - Department of Horticultural Science, College of Agriculture, University of Birjand, Birjand, Iran

Purpose: Barberry (Berberis vulgaris L.) fruit is an important source of anthocyanin supplying for consumption and in medicine. The fruit production is not regular, and based on previous studies, shows strong biennial bearing habit. Research method: The present research was conducted during ۶ consecutive years to evaluate the effects of summer pruning intensities on alternate bearing index (ABI), new shoot growth, total carbohydrate within shoot and leaf tissues, ۱۰۰ berry fresh weight, and juice anthocyanin content. Pruning treatments were done as topping the one-year old shoots in May as followed: removing ۰ bud (unpruned or control), ۱۰ buds and ۲۰ buds via topping the mentioned shoots. Findings: Data showed that summer pruning that removed ۱۰ buds via shoot topping increased the induction of new shoot growth (current shoot production), carbohydrate accumulation within shoot tissues, ۱۰۰ berries fresh weight and anthocyanin content within berry juice. On the other hand, the lowest and the highest ABI were observed in ۱۰-buds removing and un-pruned trees, respectively. Finally, it is concluded that summer pruning might be considered as a good tool to mitigate alternate bearing habit of this valuable tree, specifically decreases canopy transpiration via lower leaf area during hot periods of the season. Research limitations: During the experiment, there was no considerable limitation. Originality/Value: The present research increases the possibility of how coping with alternate bearing in seedless barberry orchards. It is clear that the changing management methods might be helpful decreasing bearing habits of this plant.

Alternate bearing, Carbohydrate, Regular shooting, barberry