Interrelationships among agronomic and seed quality traits in an interspecific soybean recombinant inbred population

The objectives of this study were to evaluate soybean [Glycine mar (L.) Merr.] agronomic and quality traits and to examine correlations among traits in an interspecific soybean population. The agronomic traits included maturity, plant canopy height, canopy spread, leaflet length, leaflet width, seed yield, and seed size. The seed quality traits were sucrose, raffinose, and stachyose content. A total of 308 recombinant inbred lines (RIL) were developed from the cross between a large-seeded Glycine mar breeding line (V71-370) and a small-seeded Glycine soja Sieb. & Zucc. accession (PI 407162). Normal distribution was observed for most of the traits with a slight skewness towards the G. soja parent. Most correlation coefficients were highly significant, such as the positive correlation between yield and sucrose and between seed size and sucrose. Genotype x environment interaction was significant for all of the agronomic traits but not for sugar contents. Maturity, seed size, and sucrose content were highly heritable, whereas plant height, canopy spread, leaflet length, leaflet width, yield, stachyose content, and raffinose content had relatively low broad-sense heritabilities. Our findings suggest that the lack of genotype x location effects on sugar content favors progress through selection, but the strong correlation among the sugars may hinder progress in selecting lines that are high in sucrose but low in raffinose and stachyose over different environmental conditions. The information on heritabililty and interrelationships among the agronomic and seed quality traits will be helpful to breeders in constructing their breeding populations and implementing selection strategies.