Comparison of Soybean Genotypes for Resistance to and Agronomic Performance in the Presence of Brown Stem Rot. Alemu Mengistu, Former Graduate Research Assistant, University of Wisconsin-Madison 53706. C. R. Grau, Associate Professor, and E. T. Gritton, Professor, University of Wisconsin-Madison 53706. Plant Dis. 70:1095-1098. Accepted for publication 14 July 1986. Copyright 1986 The American Phytopathological Society. DOI: 10.1094/PD-70-1095.

Soybean genotypes selected for resistance to Phialophora gregata in Illinois and Iowa showed moderate to high levels of resistance to P. gregata in naturally infested field plots in Wisconsin. Proportion of internal stem discoloration and severity of foliar symptoms were better measures of resistance than was percent disease incidence (based on internal stem discoloration). Mean yield of resistant lines was 17% more than yield of susceptible cultivars. Seed weight per plant was influenced more by the number of seed-bearing pods than by seed size. Host resistance could be measured in the field and was related to increased yield in the presence of brown stem rot.