Performance of Related Determinate and Indeterminate Soybean Lines1

Abstract

Previous research has produced mixed conclusions on the value of the dt1 gene for improving yield and lodging resistance in northern U.S. soybean [Glycine max (L.) Merr.] cultivars. The objective of our experiment was to compare the agronomic and developmental characteristics of determinate and indeterminate stem termination types. Twenty‐one determinate and 21 indeterminate soybean lines, randomly selected from each of three crosses, were evaluated at three Minnesota locations in 1982. Stem termination type significantly affected maturity, with the determinate lines averaging more than 3 days earlier than the indeterminate lines. The stem termination types did not differ significantly for yield. Plant height was 25.7 cm less in the determinate lines than the indeterminates. Lodging was less for the determinate lines at two of the locations, while no appreciable lodging occurred at the third location. Most location effects and location interactions with crosses and stem termination types were highly significant. The determinate and indeterminate lines had similar genetic variances in all crosses for yield, lodging, and maturity. Our observations indicate that the determinate stem termination type is potentially useful for improving yield and lodging resistance in soybeans for the northern USA. However, the production practices developed for indeterminate cultivars may need to be modified to complement the determinate stem termination type.