FROST HARDINESS OF ROOT SYSTEM OF PROMISING CLONE ROOTSTOCKS FOR PEAR

Abstract

Frost hardiness of the root system of 6 promising clone rootstocks for pears of breeding program of the All-Russian Research Institute of Fruit Crops Breeding (32A-1-9; 32A-1-24; 32A-1- 26; 32A-1-29; 32A-1-30; 32A-1-35), quince seedlings and pear seedlings were estimated by artifi cial freezing method. The results of the estimation are presented. Plants grown in container culture were kept exposed to frost 12 °C below zero. Damage degree of the root system depended both on the genotype and root thickness. Root systems in quince and pear seedlings were damaged by 70-90 % (from 3 to 4,75 points) after keeping exposed to frost. It was determined that the least damages were in 32A-1-24 (3,25 points). Quince seedlings and 32A-1-26; 32A-1-29; 32A-1-30; 32A-1-35 immaterially differed from the control - pear seedlings. Roots of 32A-1-9 were more damaged than the root system of the control (4,63 points). High regeneration ability of the root system was noted in all quince genotypes.