Analysis of promising walnut forms for resistance to return frost

In the conditions of the central zone of the North Caucasian region of Russia, in recent years, a tendency has been noted to increase the negative impact of low-temperature stressors of the winter and spring periods on walnut plants (Juglans regia L). The purpose of the study is to identify the most valuable genotypes for creating walnut varieties with increased resistance to cold stress, promising for cultivation in the south of Russia. Modern programs and methods of breeding and variety study were used. The results of a long-term study (2019-2021) of collection samples of walnuts growing in the conditions of the central zone of the North Caucasus region are presented. Highlighted hybrid forms of walnut with an early start of the growing season: 17-2-41, 17-3-44, 17-2-35, 17-2-26 (from hybrid families Ideal f. p., I -Yu-50 f. p.); and especially valuable for breeding and production genotypes with a late start of the growing season: 17-3-48, 17-3-16, 17-3-22, 17-3-19 (Dachny f. p., Ya-B-84 f. p.). It has been established that all hybrid seedlings from families (Ideal f. p., Ya-Yu-50 f. p., Ya-Yu-40 f. p., Dachny f. p.) of walnut are moderately resistant to returnable spring Frost