Specific Virulence of Puccinia recondita f. sp. tritici in the United States from 1978 Through 1983. D. L. Long, Plant Pathologist, Cereal Rust Laboratory, USDA, ARS, Department of Plant Pathology, University of Minnesota, St. Paul 55108. J. F. Schafer and A. P. Roelfs, Research Plant Pathologists, Cereal Rust Laboratory, USDA, ARS, Department of Plant Pathology, University of Minnesota, St. Paul 55108. Plant Dis. 69:343-347. Accepted for publication 23 October 1984. 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, 1985. DOI: 10.1094/PD-69-343.

Puccinia recondita f. sp. tritici was identified from wheat leaf collections made by cooperators throughout the United States and from cereal rust field surveys of the Great Plains and Gulf Coast from 1978 through 1983. Testing of 1,928 isolates for virulence to 12 single-gene resistant tester lines showed 33 virulence combinations, which were categorized into 12 Unified Numeration (UN) races. Ninety-five percent of the isolates were classified into six UN races. No virulence was found to Lr16 or 19.

Keyword(s): wheat leaf rust.