Study on seed yield components depending on the duration of vegetation period in soybean

Galina Naydenova, Natalia Georgieva

Abstract: Avoidance of drought by using varieties with rapid phenological development or displacement of critical phenological periods through the variety are effective approaches to stabilizing soybean yields under non-irrigated conditions in Bulgaria. This requires when selecting genetic resources for our breeding program, the study of seed productivity and structural yield components to be made in relation to the duration of the vegetation period. With such aim twenty-eight cultivars of different maturity groups were studied during three year in a field trial conducted in the long-plot design method on the soybean technology established for the country. According to the results presented, a high and stable performance regarding the traits determining the seed productivity could be considered in connection with the maturity group of genotypes. In selection for "large-seedness" as parental components should be used genotypes with high expression of the trait from the early-ripening or middle late-ripening group of maturity. The average values, but also the ecological dispersion of the traits number of fertile nodes and number of branches were higher in genotypes with a longer vegetation period, and also early-ripening genotypes with a high and ecologically stable expression on these traits were established in this study. Individual productivity, estimated by the number and mass of seeds obtained from a plant, has the most stable performance in Bulgarian cultivars and can be considered to be a function of the specific adaptation of genotypes. Also there is a trend for a higher yield of seed from a plant in genotypes with shorter growth period which can be associated with better seed filling.

Keywords: seed yield components; soybean; variance components

Date published: 2019-02-05