Effects of Soybean Seed Size, Vigor, and Maturity on Crop Performance in Row and Hill Plots1

Abstract

Soybean [Glycine max [L.] Merr.] seed size (mg seed−1) has been shown to vary considerably within and among seed lots. This investigation was conducted to determine the effect of seed size and vigor on crop performance when planted in hill and row plots. Seed lots of mature and immature seed (‘DeSoto’) were selected to have a range in seed size (68‐212 mg seed−1) and seed vigor (low to high) but acceptable standard germination (> 82%). These seed lots were evaluated for crop performance in two field experiments: bordered row plots (1983–1985) and unbordered hill plots (1984,1985). Near ideal soil conditions at planting resulted in excellent field emergence, and adequate plant populations occurred for all seed lots in both field experiments. Field emergence was significantly correlated with seed vigor, but showed little relationship to seed size. Both seed size and vigor positively influenced plant height at growth stages R2 and R7. Seed yield (kg ha>) of row plots was not significantly related to seed size or vigor in the 3 yr evaluated. Yields in row plots were similar across a wide range in seed size and vigor even for immature seed lots harvested prior to physiological maturity (growth stage R7). In hill plots, the seed yield (g plot 1) was significantly related to both seed size and vigor with lower yields occurring for seed lots with low vigor and with smaller size (< 100 mg seed−1). This yield response in hill plots was especially evident for immature seed lots; therefore, precautions should be taken to evaluate seed lots for seed size and vigor before testing in unbordered hill plots.