Gene pool assessment in terms of apple tree generative organs resistance of different ploidy to spring frost

Russian Research Institute of Fruit Crop Breeding (VNIISPK), Zhilina, Orel district, Orel region, Russian Federation

^* Corresponding author: krasovang@vniispk.ru

Abstract

The results of resistance studies of apple varieties (Malus domestica L.) generative sphere to low temperatures during flowering are presented. The research was carried out on the basis of areas of primary and industrial study of apple varieties and laboratory of physiology of stability of fruit crops of Russian Research Institute of Fruit Crop Breeding in the period 2009-2020. The resistance of the generative organs of the apple tree to spring frost was determined by the method of frost modeling from -1.0°C to -6.0°C. The purpose of the research is to establish a critical temperature to identify the stability of the generative sphere to frosts during flowering, to identify the reaction of different ploidiness varieties to low temperatures in flowering time and identify resistant ones. As a result of frost modes modeling, the critical temperature for flower elements (-3.5°C) was established, and apple varieties resistant to critical temperature were allocated. When using the non-parametric Mann — Whitney criterion, in different phases of flowering reliable (at the value level p = 0.05) differences in the genotypes resistance of different ploidy to the simulated spring frosts were identified. Weak stability of the generative sphere in studied triploid (3n) varietal specimens in comparison with diploid (2n) has been established. Critical temperature was taken by diploid varietal specimens with less damage to flowers and buds (11.3% in Antonovka obyknovennaya to 55.3% in Imant) than triploid (from 61.0% in ELS 30-30-114 to 100% Rozhdestvenskoye). Varieties Bolotovskoe, Imrus, Veteran, Kulikovskoe, Orlik with resistance of the generative sphere to frost are recommended for intensive plantings.