THE INFLUENCE OF ROOTSTOCK ON THE FROST RESISTANCE OF SWEET CHERRIES DURING THE THAW

Abstract

Studies on the frost resistance of sweet cherries were carried out in 2019–2020 in the FSBSI of the Federal Horticultural Research Center for Breeding, Agrotechnology and Nursery in laboratory conditions by artificial freezing in the climate chamber TH-6 JEIO TECH-1000. Objects of research: Tyutchevka and Chermashnaya varieties grafted on 8 clonal rootstocks (Colt, Izmailovsky, AVCH-2, V-5-88, VC-13, Moskoviya, VSL-2, Stepnoy Rodnik). The aim of the research is to study the effect of clonal rootstocks on the frost resistance of cherry buds and tissues during the thaw and to identify the most frost-resistant scion-rootstock combinations for the 3rd component. It was found that after freezing at t = -20 °C during the thaw, the safety of flower buds in the Tyutchevka variety in both years of research was more than 80 %, and in the Chermashnaya variety — from 20 to 30 %, depending on the year. The limits of changes in the frost resistance of generative buds of varieties depending on the rootstock are shown: in the Tyutchevka variety — from 66.8 % (V-5-88) to 96.4 % (Izmailovsky), and in the Chermashnaya variety — from 7.7 % (V-5-88) to 65.5 % (AVCH-2). When using the AVCH-2 and Izmailovsky clonal rootstocks, the safety of flower buds increased by 30 % compared to the Colt rootstock. The most frost-resistant scion –rootstock combinations for each variety were identified: Tyutchevka/Izmailovsky and Tyutchevka/Stepnoy Rodnik, which preserved more than 90 % of the living rudiments; Chermashnaya/AVCH-2 (65.5 %) and Chermashnaya/Izmailovsky (40.1 %). Vegetative buds and tissues of annual branches were practically free of freezing in the studied varieties when grafted on the rootstocks of Stepnoy Rodnik and AVCH-2. In the Chermashnaya variety, damage of about 1 point of the phloem and vascular bundle under the buds was noted when grafting on rootstocks V-5-88 and Colt.