Barberry (Berberis vulgaris L.) fruit is an important source of anthocyanins and is used for consumption and in medicine. However, fruit production of barberry is not regular. Two experiments in four locations were conducted on this plant to explore if it is alternate bearer and also to investigate carbohydrates and phenolics contents in leaves and shoots during growth season. Evaluation of barberry shrubs in three different location showed strong alternate bearing. The value of leaf number to berry number ratio was small. A correlation was found between tree age and alternate bearing index (ABI), because elder shrubs exhibited more ABI. Total carbohydrates and phenolics contents in vegetative organs showed an increase during the fruit setting stage, except for the carbohydrates in shoots. The highest value of carbohydrates was observed 10 days after leaf appearance and then decrease. ON bearing shrubs showed the highest value of total carbohydrates content in leaves during fruit setting stage, after which it decreased. However, OFF bearing shrubs indicated a reducing trend in this variable. In both bearing statuses (ON and OFF trees), total carbohydrates decreased with season progression. It is concluded that this plant is strongly alternate bearer and this characteristic may be related to carbohydrates and phenolics changes in leaf and shoot organs.

The present study was designed to investigate the effects of two girdling dates (late April and early September) on fruit quality and carbohydrate accumulation in barberry shrubs (Berberis vulgaris L.) during the years 2016–2017. One year old shoots were ringed and fruit characteristics were monitored for two continues year. Data showed that the girdling caused a significant increase in the ascorbic acid content in fruit. Similarly, anthocyanin and total acidity were affected by girdling compared to control in 2017. September-girdled shrubs had the highest amount of fresh mass but the dry mass was not changed. It was shown that chlorophyll b increased in the girdled shrubs compared to control. September girdling reduced the carbohydrate content in leaves. In contrast, it increased the carbohydrate content in shoots. In addition, there was a significant difference between starch in the shoot and starch in leaf. Owing to the obtained results, early September girdling caused a broad range on fruit quality.