Effect of Seed Source on Soybean Strain Performance for Two Successive Generations1

Abstract

We evaluated the performance of 10 soybean [Glycine max (L.) Merr.] strains by planting seed produced at each of 14 diverse locations in 1967. Significant differences among sources were observed for all characters evaluated. The importance of the range among sources for yield (176 kg/ha), maturity (1.5 days), lodging (0.16 score), height (2.1 cm), seed size (0.59 g/100 seed), field emergence (46.7%), protein percentage (0.50%), and oil percentage (0.23%) will depend on the desired accuracy of strain comparisons. The strains ✕ sources interaction was significant only for maturity and field emergence percentage, indicating that relative performance of strains was consistent across sources.Significant differences among seed sources were detectable for one crop season only, except for maturity and seed size. The range among sources in the second crop season was 0.3 days for maturity and 0.21 g/100 seeds for seed size.Geographical distance between sources was not a reliable indication of potential first‐generation differences among sources. Germination percentage and seed size were not useful as direct indices of differences among sources. However, seed lots of a particular genotype that differ appreciably for either character are likely to have differences in progeny performance.Differences due to seed source may be minimized by growing all test strains, including checks, in the same environment immediately before testing. The persistence test indicated that one common environment immediately before testing is adequate to minimize differences of practical importance.