Genetic Variability for Soybean Seed Composition in Crosses Between High- and Low- Protein Parents

Abstract

The genetic variability for seed composition between high and low protein soybean (Glycine max (L.) Merr.) parents was evaluated. Wells and Woodworth were the low-protein cultivars, and PI 153.269 and Pando were plant introductions with high protein content. Wells was crossed to PI 153.269 and two back crosses to Wells were obtained. Woodworth was crossed to Pando, and two backcrosses were made to Woodworth.  F₂-, BC₁F₁-, and BC₂F₁-derived lines and the parents were evaluated in two environments. Protein and oil percentages were measured by infrared analysis. No line from either set of crosses had protein concentrations as high as those of the high-protein donor parent. The F₂-derived line with the highest protein from the cross Wells x PI 153.269 had 48.0%, whereas PI 153.279 had 49.4%. In the Woodworth x Pando cross, the best F₂-derived line had 46.0%, whereas Pando had 49.2%. Mean protein percentage and genetic variance of the populations decreased with each backcross. Broad sense heritabilities on an entry mean basis ranged from 0.76 to 0.89. Discussed here are the implications of these findings in relationship to a breeding method tor protein improvement.