VIEW ARTICLE

Resistance

Twelve Pyrenophora trichostoma Races for Virulence to Wheat in the Central Plains of North America. Wilmar Cório da Luz, Graduate student, Department of Plant Pathology, North Dakota State University, Fargo 58105, Senior author's current address: Centro Nacional de Pesquisa de Trigo, Caixa Postal 569, Passo Fundo 99100 RS BRAZIL; R. M. Hosford, Jr., professor, Department of Plant Pathology, North Dakota State University, Fargo 58105. Phytopathology 70:1193-1196. Accepted for publication 5 June 1980. 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, 1980. DOI: 10.1094/Phyto-70-1193.

Forty isolates of Pyrenophora trichostoma from the Central Plains of North America were separated into 12 races for leaf spotting virulence on six wheat cultivars. The wheats were separated into six differentials for resistance. BH1146 spring wheat from Brazil was resistant to the largest number of races. These isolates and cultivars are the basis for a system for the determination of genes for virulence and resistance. Larker barley was resistant to all 40 isolates. The fungus also caused "black point" of wheat seed and brown spots on glumes and awns.