The influence of seed size on soybean yield in short-season regions
Two field experiments were done to determine if simple mechanical selection for seed size in soybean (Glycine max L. Merr.) could improve emergence and yield in short-season regions. Stacked screens with round holes 7.54, 7.14, 6.35 and 5.95 mm in diameter classified seeds into large, medium, small, and unscreened sizes. In exp. 1, small seeds resulted in lower yield than medium, large and unscreened seeds in two out of three cultivars, while in the third cultivar small seeds yielded less than the medium and large seed sizes, but were not significantly different from the unscreened size. In exp. 2, soil texture and seed size had a variable influence on seed emergence, which did not translate into consistent significant yield differences. Future research into mechanically removing small seeds from commercial seed lots is warranted in the short-season region. Key words: Seed size, soil texture, soybean, Glycine max L. Merr.