Transgressive variability of the main ear grains number in F 2 populations in hybridization of soft winter wheat varieties that differ in early ripening

Abstract

The studies conducted in the contrastive by their hydrothermal conditions 2019–2020 examined F 2 hybrid populations created by crossing different early ripening varieties of soft winter wheat. Most of F 2 populations used in various crossbreeding schemes of early ripening, middle-early, medium-ripening, and middle-late varieties for both average number of grains in the ear and its maximum manifestation, signifcantly exceeded the original forms and characterized by signifcant formation. The obtained results indicate a signifcant influence of the selected pairs for hybridization and hydrothermal conditions of the year on the formation of the number of grains in F2 populations of soft winter wheat. However, hybrid populations with early ripening varieties as the maternal form are less susceptible to adverse hydrothermal conditions. The research results give ground for defning hybrid populations, which had less than the average number of grains in the ear for F 2 in the most contrastive hydrothermal conditions and were characterized by high rates and frequency of positive transgressions, namely: Myronivska early / B.Ts. semidwarf; Myronivska early / Zolotokosa.; Myronivska early / Chorniava; Kolchuga / Stolychna; Myronivska early / Vdala; Shchedra nyva / Vidrada; Antonivka / Stolychna. The identifed correlations between the degree of phenotypic dominance in F1 and the degree and frequency of positive transgressions indicate an insignifcantly weak direct to inverse relationship between these indicators. At a reliable level, in the years of research, a strong (r = 0.774…0.893) correlation was found with the degree of positive transgressions and the frequency of recombinants. Key words: degree and frequency of transgression, soft winter wheat, maturity groups, parental forms, variability, number of grains of the main ear, population F2, degree of phenotypic dominance.