Evaluation of the effects of hand and chemical thinnings on some quantitative and qualitative traits in the fruits of the seedless barberry

Generally, fruit trees should produce sufficient yield annually through their economic life. Fruit trees usually produce flowers over their ability of productivity. If all of the flowers are converted to fruit, the tree will be weak and poor smaller fruit will be produced and it may cause alternate bearing. Thus some flowers must be removed by hand, mechanically or chemically. In this study, the effects of hand thinning (10, 20 and 40 percent cluster elimination) and foliar treatment of Naphthalene Acetic Acid (5, 10, 20 and 40 mg/l) and ethephon (25, 50, 100 and 200 mg/l) on fruit thinning rate and on some quantitative and qualitative characters of seedless barberry fruit were investigated as a completely randomized block design in research garden of Birjand University in 2014. The results indicated that Naphthalene acetic acid and Ethephon application caused effective fruit thinning. The highest rate of thinning was observed in Naphthalene acetic acid (10 mg/l) and ethephon (50 mg/l) treatments. These treatments also increased the yield rate in comparison to control. Hand thinning, Naphthalene Acetic Acid and Ethephon application increased the length, diameter and volume of fruit, fresh weight (100 berry), dry weight (100 berry), anthocyanins, ascorbic acid, total soluble solids, total soluble solids to acid ratio. Thus both chemical treatments are suitable and ethephon (50 mg/l) is the best treatment.