Genetic Variability for Flooding Tolerance in Soybeans

Abstract

The flooding tolerance of U.S. soybean [ Glycine max (L.) Merr.] cultivars under field conditions has not been reported. In this study, 84 soybean cultivars of maturity groups II, III, and IV were grown at two locations, London and Lakeview, in Ohio. The cultivars differed in their resistance and tolerance to Phytophthora sojae M.J. Kaufmann & J. W. Gerdemann as determined in separate field and laboratory studies. While the production practices and historic yield potential at the two locations were similar, the nearly flat, slowly permeable Milford silty clay soil at Lakeview was saturated during most of July 1992 because of excessive rainfall (17 cm more than normal). The average yield of the 84 soybean cultivars at the flooded location (Lakeview) was 25% lower than at the non‐flooded location (London). Flooding tolerance can be defined as high yield under flooding stress. When the 84 soybean cultivars were ranked in their flooding tolerance according to this definition, many cultivars were found to exhibit both flood tolerance at Lakeview and high yield at London. Flooding tolerance was independent from Phytophthora tolerance, Phytophthora resistance, and plant relative maturity. This study documented that differences in flooding tolerance exist among U.S. soybean cultivars.