Inheritance of Resistance to Powdery Mildew in Soybeans. D. G. Lohnes, Agronomy Department, University of Illinois, 1102 S. Goodwin Avenue, Urbana 61801. R. L. Bernard, Agronomy Department, University of Illinois, 1102 S. Goodwin Avenue, Urbana 61801. Plant Dis. 76:964-965. Accepted for publication 13 April 1992. Copyright 1992 The American Phytopathological Society. DOI: 10.1094/PD-76-0964.

Reaction of soybeans (Glycine max) to powdery mildew (Microsphaera diffusa) has been reported to be regulated by a single gene pair Rmd rmd, with the dominant allele Rmd activating adult-plant resistance and rmd causing susceptibility. Resistance from the seedling stage on was observed in the greenhouse in several soybean cultivars, and these cultivars were resistant in the field with natural and artificial inoculation. F₂ and F₃ segregation ratios in the greenhouse and field show that this resistance, derived from the cultivar CNS, is controlled by a single allele, symbolized Rmd-c, which is allelic to Rmd rmd.