Influence of root growth force on morphological indicators of development of above-ground part of spur-growing varieties of apple

The scientific article provides experimental material devoted to the study of morphological signs of development of apple rootstocks of various strengths and grafted apple varieties of the “spur” type on them.The study was carried out at the central experimental base of the Research Institute of Horticulture, Viticulture and Winemaking named after M.M. Mirzaev in 2015–2020.The objects of the study were: seed stock of Sievers apple tree, vegetatively propagated low-growing stocks MM 106 and M 9, as well as spur apple varieties Starking Delicious, Starkrimson, Redspur Delicious, Velspur, Hordispur, Vinespur, Golden Delicious, Goldspur Ispur, Yesspur, Yesspur. The trees in the garden were placed according to 5x4, 5x3 and 5x2 meters. In each variant, according to the replicates of the experiment, five trees were counted. During the growing season, the development of trees was controlled by the following phenological observations and biometric counts: the number of formed shoots of the current year in the crown, their average length, height, diameter and volume of the crown.Studies have shown that the most developed trees are formed when the seedlings of the Sievers apple tree are used as a rootstock. Moreover, higher rates among apple varieties of the “spur” type are observed in the spur varieties of the Golden Delicious clone.