Genetic and statistical analysis of the combiniting ability of spring wheat varieties for drought resistance in the juvenile period of development

Eight original forms and 16 hybrid populations of F2 spring wheat of the 2019 yield were studied to determine the level of drought resistance by sprouting seeds in a sucrose solution during 5 days. The effect of artificially created drought on seedlings was very significant: the overall decrease in seed germination in parents and hybrids was 16.0 and 16.7 %, respectively, the number of seminal roots – 19.3 and 17.4 %, the weight of the seedling – 67.1 and 70.2 %. Under stressful conditions, the root-shoot ratio (RSR index) increased on average from 0.92 to 1.42 in varieties and from 0.86 to 1.68 in hybrids. High varietal specificity of both absolute values of traits in the control and the experiment, as well as the response to stress, was noted. By the number of seminal roots in the control, the NOS Norko variety (Germany) had the advantage, and by the weight of the seedling – Karabalykskaya 91 (Kazakhstan). Significantly high values of the RSR index in the control and the experiment were observed in the Jahuara F-77 variety (Mexico). The Kitt variety (USA) was characterized by lack of response to drought of seed germination. The Jahuara F-77 (Mexico) and Klein Vencedor (Argentina) varieties were characterized by lack of response to drought by the number of seminal roots. Based on the analysis of the general and specific combinational ability of parent varieties, 8 promising hybrid combinations were identified. A high heterosis effect, expressed by an increase in the average value of the trait in hybrids relative to parents, was observed in most hybrid combinations by the parameter "seedling mass", in the combination of Erythrospermum 2945 x NOS Norko - by the number of seminal roots. The influence of maternal and paternal components as well, as their interaction, on the germination of F2 hybrids seeds was insignificant (the inheritance coefficient h02 = 0.04...0.22). The contribution of parent varieties to other parameters in the control was significantly high (Ffact > F05), except for the influence of paternal forms on the weight of the seedling. The values of the general heritability coefficients of the number of roots and RSR under normal conditions (h02 = 0.80...0.82) indicate that selection by these parameters can be highly effective. In artificially created drought, the most efficient will be the selection by the "dry weight of seedling" parameter, since the contribution of maternal components in the number of seminal roots and paternal components to the RSR index is insignificant.