New Physiologic Race of Phytophthora megasperma f. sp. glycinea. Alice C. Layton, Research Assistant, Department of Biochemistry, Purdue University, West Lafayette, IN 47907. K. L. Athow, Professor, and F. A. Laviolette, Associate Professor, Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN 47907. Plant Dis. 70:500-501. Accepted for publication 10 December 1985. Copyright 1986 The American Phytopathological Society. DOI: 10.1094/PD-70-500.

A new physiologic race of Phytophthora megasperma f. sp. glycinea has been identified after hypocotyl inoculation of the differential soybean (Glycine max) cultivars Harosoy, Harosoy 63, Sanga, Mack, Altona, PI 171442, and PI 103091. The new race was proposed as number 25. Race 25 is compatible with or virulent to those cultivars with the following genes at the rps₁ locus: Rps₁, Rps₁^b, Rps₁^c, Rps₁^k, and Rps₁^Har but incompatible with or avirulent to those cultivars with the genes Rps₃, Rps₄, Rps₅, and Rps₆.