Abstract
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, Rps1b, Rps1c, Rps1k, and Rps1Har but incompatible with or avirulent to those cultivars with the genes Rps3, Rps4, Rps5, and Rps6.