PRODUCTIVITY OF APPLE TREES DEPENDING ON THE SHAPE OF THE CROWN AND THE TIME OF PRUNING

Abstract

Apple trees are the main fruit crop in Ukraine both in terms of fruit production and the area of fruit plantations. In modern horticulture, preference is given to intensive cultivation technologies that can ensure the maximum amount of quality fruit per unit area. The main method of solving this technological problem is the design of the orchard: reducing the tree planting scheme and forming low-volume crown shapes. The article presents the results of the research on the influence of crown shape and the term of their pruning on the productivity of apple trees of winter ripening varieties. The research was conducted in 2019–2022 in the apple orchard of the Uman National University of Horticulture. The objects of the research were apple varieties Fuji and Honey Crisp grafted on rootstock M.9 and planted according to the 4 x 1 m scheme. Three crown shapes were studied: a slender spindle, a ballerina with the removal of overgrown wood on the central conductor to form a "window" above the branches at the base of the crown, and a French axis. The trees were pruned in winter and summer after the June ovary shedding. It was found that the number of fruits prevailed in Fuji trees, but their weight was inferior to Honey Crisp. As a result of the French axis crown formation with the removal of a significant amount of wood, tree productivity (number of fruits and yield) was significantly inferior to other research options, despite the increase in fruit weight to 167 g. Due to the peculiarities of the ballerina crown design and its better illumination, slightly higher values of tree productivity were obtained. The number of fruits increased by 4%, fruit weight by 11%, and plantation yield by 15% compared to the traditional slender spindle crown. The positive effect of the introduction of additional summer pruning on the increase of both fruit weight (by 9%) and the level of productivity of apple trees by 22.6% was also noted.