Tentative Identification and Verification of Genes for Leaf Rust Resistance in Wheat Cultivars of South Dakota. SYED SHABBIRAZHER RIZVI, Former Graduate Research Assistant, Plant Science Department, Box 2109, South Dakota State University, Brookings 57007. GEORGE W. BUCHENAU, Professor, Plant Science Department, Box 2109, South Dakota State University, Brookings 57007. Plant Dis. 78:674-679. Accepted for publication 4 March 1994. Copyright 1994 The American Phytopathological Society. DOI: 10.1094/PD-78-0674.

Thirty-three winter and spring wheat cultivars and 26 single-gene wheat leaf rust {Lr) lines were inoculated with 21 isolates of Puccinia recondita and the resulting infection types were compared to detect the existence of possible resistance genes in the cultivars. To verify the presence or absence of the hypothesized gene, cultivars were crossed to lines containing single putative resistance genes and F2 populations were inoculated with appropriate P. recondita isolates. Some hypothesized genes verified in the cultivars were: Lr3 in Bennett, Brule, Lancer, Rita, and Rose; Lr10 in Butte; Lr1 + Lr10 in Pavon 76; Lr2a + Lr10 in Len; Lri + Lr10 in Dawn, Nell, and Wheaton; Lr1 + Lr2a + Lr10 in A99AR and Challenger; Lr2a + Lri + Lr10 in Alex, Erik, Guard, Marshall, Norak, Norseman, Olaf, and Oslo; Lr3 + Lr10 + Lr24 in Butte 86, Centura, and Sage; Lr3 + Lr10 + U26 in Pakistan 81 and Sarhad 83; Lr1 + Lr2a + Lr3 + Lr10 in Shield and Punjab 83; and Lr3 + Lr10 + Lr24 + Lr26 in Siouxland.