BREEDING AND GENETIC FEATURES OF SOYBEAN VARIETIES BASED ON THE MANIFESTATION OF TRAITS IN F1 HYBRIDS IN TOPCROSSES

Abstract

Further increase in gross soybean production requires the introduction of new varieties with an optimal combination of elements of the crop structure. Hybridization in soybeans is the main effective method of creating new varieties. Increasing the efficiency of hybridization in obtaining heterotic offspring is possible when using parental forms with high combinational ability in crosses. In the study, a two-tester analysis of topcrosses of soybean varieties differing in economically valuable traits was used. Based on the results of the combinational ability assessment, the value of soybean varieties was determined by the elements of the yield structure. Heterotic combinations in first-generation hybrids were identified, from which it is more likely to select highly productive forms in later hybrid populations F2-F4. The high effects of ZKZ and SCZ on plant height in varieties Medea, Kyivska 97, Sawyer 2-95 and KiVin tester; on the height of lower bean attachment in varieties Sawyer 2-95, Ustia, Kharkivska skoroglya and KiVin tester; on the number of productive nodes - in varieties Kyivska 97 and Goverla tester; by the number of beans per plant - in varieties Sawyer 2-95, Kyivska 97 and tester Goverla; by the number of seeds per plant - in varieties Medea, Kyivska 97 and tester KiVin; by the weight of 1000 seeds - in varieties Sawyer 2-95, Kyivska 97 and tester Goverla; by the weight of grain per plant - in varieties Sawyer 2-95, Kyivska 97 and tester Goverla. It was found that additive effects of genes were predominant in the genetic control of plant height and lower bean attachment, elements of yield structure and grain weight per plant, but there is a smaller influence of non-additive effects. The manifestation of true heterosis (dominance in 100% of cases) in hybrids (F1) was found in crosses with both testers for the number of productive nodes, number of beans and seeds per plant, and grain weight per plant.