Inheritance of quantitative traits and the effect of heterosis in first-generation soybean hybrids

The results of a selection and genetic analysis of the inheritance of essential economically beneficial traits by first-generation soybean hybrids according to the degree of phenotypic dominance and heterosis are presented. The authors considered an assessment of 18 hybrid soybean combinations based on four quantitative characteristics that make up productivity: the number of beans, the number of seeds, the weight of seeds per plant, and the weight of 1000 seeds. The research was conducted in the selection and primary seed production laboratory of the Federal State Budgetary Institution Federal Scientific Center All-Russian Research Institute of Soybeans in 2021–2022. Soybean samples for hybridization were selected using an ecological-geographical principle. The authors used the highly productive soybean varieties bred by the Federal Scientific Center All-Russian Research Institute of Soybeans as maternal forms: Sentyabrinka, Kukhanna; as paternal forms, varieties and samples from the American, European, and Asian ecological-geographical zones. The authors carried out the Artificial intraspecific hybridization in 2021 according to the method of K.K. Baby and T.P. Ryazantseva. As a result of the research, the nature of inheritance of the leading economically beneficial traits in intraspecific F1 soybean hybrids was determined. The degree of manifestation and magnitude of heterosis varied greatly depending on the combination of crossing and the trait being studied - from overdominance to depression. It has been established that the effect of heterosis and overdominance in all four indicators: the number of beans, the number of seeds, the weight of seeds per plant, and the weight of 1000 seeds (hp = 1.14–23.96; G = 2.85–23.26%) – recorded in two promising combinations with the paternal form from the American ecological-geographical zone: ♀ Sentyabrinka x ♂ Saska (Canada) and ♀ Kuhanna x ♂ Saska (Canada). A high degree of phenotypic dominance (hp = 1.65–18.54) and heterosis (G = 5.04–44.53%) in terms of the number of beans, the number of seeds, and the weight of seeds per plant were noted in combination with paternal forms from the American (♀ September x ♂ Kyoto (Canada)), European (♀ September x ♂ Cordoba (Austria)) and Asian (♀ September x ♂ Heihe 12 (PRC)) ecological-geographical zones. These hybrid combinations are of great interest in breeding research for high productivity in the Amur region.