Effects of Prohexadione-Calcium on ‘Monroe/GF 677’ Peach Vegetative Shoot Growth, Fruit Yield and Quality

Prohexadione-calcium (Pro-Ca) is a recently developed plant growth retardant used in some fruit trees. However, it is important that the reduction of vegetative shoot growth does not decrease yield and fruit quality. In this study, the effects of Pro-Ca applications on the vegetative growth and some fruit quality of the Monroe peach, growing on vigor rootstock (GF 677) were investigated. For this reason, trees were sprayed twice with 0 (water + surfactant), 62.5, 125, 250 g 100 L water Pro-Ca in the annual shoots reached 5 cm within a three week interval in the spring of 2018 and 2019 years. Shoot length was decreased by 28-32% for shoots treated with Pro-Ca. The average internode length was significantly reduced for Pro-Ca-treated shoots. The lowest average internode length on the shoot was obtained with 125 and 250 g 100 L. The effects on fruit quality were positive in this study. Application of Pro-Ca (125 and 250 g 100 L) increased the fruit size and fruit mass of cv. Monroe’ peach. 250 g 100 L Pro-Ca concentration led to firmer fruit relative to the other applications and control fruits. Two application 125 or 250 g 100 L Pro-Ca applications were found more effective considering the criteria investigated. The Pro-Ca applications were found to be effective in controlling the vegetative shoot growth and fruit quality in cv. Monroe/GF-677 peach.