Identification of Powdery Mildew Resistance Genes in Cultivars of Soft Red Winter Wheat. Steven Leath, USDA-ARS and Department of Plant Pathology, North Carolina State University, Raleigh 27695-7616. Manfred Heun, Lehrstuhl für Pflanzenbau und Pflanzenzüchtung, D-8050 Freising-Weihenstephan, FRG. Plant Dis. 74:747-752. Accepted for publication 12 February 1990. This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. The American Phytopathological Society, 1990. DOI: 10.1094/PD-74-0747.

Twenty-two soft red winter wheat (Triticum aestivum) cultivars were inoculated with isolates of Erysiphe graminis f. sp. tritici to determine genes for resistance. Cultivars were tested with a total of 27 isolates that had been characterized from reactions on differential host lines. Gene determinations were completed separately in two laboratories with different isolates and the results were combined. Intact 10-day-old seedlings or detached primary leaves on benzi-midazole-amended agar were inoculated, and evaluations based on pustule number and type were made 10–14 days later. Resistance genes were postulated based on application of the gene-for-gene concept and pedigree analysis. One cultivar was not fully characterized, while results indicated some cultivars carried no known powdery mildew resistance genes (Pm). The genes Pm3a, Pm5, and Pm6 were present in some of the cultivars tested.