Sources of Genes Resistant to Puccinia hordei in Barley. E. L. Sharp, Professor of Plant Pathology, Department of Plant Pathology, Montana State University, Bozeman 59717. M. Reinhold, Postdoctoral Fellow, Department of Plant Pathology, Montana State University, Bozeman 59717. Plant Dis. 66:1012-1013. Accepted for publication 24 February 1982. Copyright 1982 American Phytopathological Society. DOI: 10.1094/PD-66-1012.

A total of 178 barley (Hordeum vulgare) cultivars or lines were evaluated to 12 isolates of Puccinia hordei from the United States and the Mediterranean area. The genes Pa₃ and Pa₇ of barley were effective against all 12 isolates. Two lines of barley apparently not possessing either the Pa₃ or Pa₇ gene were also resistant to all cultures of P. hordei. The Pa₉ gene in the barley line CI 1243 was overcome by only one isolate of P. hordei from Israel, which originated from the alternate host (Ornithogalum sp.). Differences in infection types with cultivars reported to carry the gene Pa₂ indicated the presence of more than one gene. Twenty-eight potentially useful resistance sources effective against more than 50% of the isolates were detected. Several cultivars contained resistance genes apparently different from any Pa gene previously described.

Keyword(s): barley leaf rust.