Resistance in Sorghum to Seedling Disease Caused by Pythium arrhenomanes. G. A. Forbes, Graduate Research Assistant, Department of Plant Pathology and Microbiology, Texas Agricultural Experiment Station. O. Ziv, and R. A. Frederiksen. Professor, The Volcani Research Center, Bet Dagan 50200, Israel; and Professor, Department of Plant Pathology and Microbiology, Texas Agricultural Experiment Station, College Station 77843. Plant Dis. 71:145-148. Accepted for publication 21 July 1986. Copyright 1987 The American Phytopathological Society. DOI: 10.1094/PD-71-0145.

Resistance to infection by Pythium arrhenomanes was identified in the grain sorghum cultivar QL3(India). Both field and laboratory tests were used to establish QL3(India) and SC748-5 as resistant and susceptible candidates, respectively. The relative resistance in QL3(India) was tested under controlled conditions. Leaf length, leaf dry weight, and root dry weight were reduced 53, 43, and 42%, respectively, in SC748-5 as a result of infection. Reductions in the same variables for QL3(India) were 10, 6, and 15%, respectively. Resistance was associated with differences in secondary root production and lesion size.