Resistance to Wheat Stem Rust in Spring Spelts. D. V. McVey, Cereal Rust Laboratory, United States Department of Agriculture, Agricultural Research Service, University of Minnesota, St. Paul, MN 55108. K. J. Leonard, Cereal Rust Laboratory, United States Department of Agriculture, Agricultural Research Service, University of Minnesota, St. Paul, MN 55108. Plant Dis. 74:966-969. Accepted for publication 13 April 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-74-0966.

The minimum number of Sr genes for resistance to wheat stem rust (caused by Puccinia graminis f. sp. tritici) was determined from infection-type data of the interaction of spring habit spelts (Triticum spelta) and wheat stem rust. Infection-type data from seedlings infected with 35 isolates of P. g. f. sp. tritici were used to determine low or high infection-type of 578 spelt introductions of the USDA National Small Grain Collection. A “boxing” program based upon the gene-for-gene concept was used to identify corresponding gene pairs. Of the minimum 28 genes for resistance to stem rust present, 26 were new. More genes were probably present, and a few in combination could provide a useful level of resistance to stem rust.