Reduction of apple vegetative shoot growth cv. Starcrimson Delicious/MM 111 with prohexadione calcium application does not decrease fruit quality

Prohexadione-calcium % 10 (Pro-Ca) has been shown to effectively reduce the vigor of apple trees. However, it is important that the reduction of vegetative shoot growth does not decrease yield and fruit quality. The primary objective of this study was to determine the response of Starcrimson Delicious/MM111 apple trees to foliar Pro-Ca application and its effect on vegetative growth and fruit quality. For this reason, trees were sprayed twice within a three weeks interval with 62.5, 125, 250 g/100 L water Pro-Ca when annual shoots reached 5 cm. Pro-Ca applications decreased the growth of annual shoots and shoot length of apple trees. Shoot length was decreased by 31% for shoots treated with P-Ca. The number of nodes and average internode length were significantly reduced for P-Ca-treated shoots, conferring a higher node density relative to control shoots. Three weeks intervals of application Pro-Ca applied shoot 125 and 250 g/100 L water dosage is more effective in terms of reducing the development. Fruits from Pro-Ca treated trees did not significantly differ in size or other observed quality characteristics (firmness, soluble solids content (SSC), titratable acidity (TA), and fruit color) from fruits from the control group. As a result, application Pro-Ca of 125 g/100 L dosages for ‘Starcrimson/MM111 apple varieties can be recommended.