Genes for Leaf Rust Resistance in Hard Red Winter Wheat Cultivars and Parental Lines

Abstract

Knowledge of the genes for resistance to leaf rust caused by Puccinia recondita Roberge es Desmaz. f. sp. tritici present in bread wheat (Triticum aestivum L.) cultivars and breeding lines is useful in developing resistant cultivars, estimating potential disease loss, and determining pathogen over‐wintering. The objective of this study was to postulate the known Lr genes conferring low seedling reaction in 30 cultivars and 56 hard red winter wheat breeding lines from nine winter wheat breeding programs. Entries were inoculated with 17 isolates of P. r. L sp. tritici previously characterized for avirulence/virulence to 16 Lr genes. The genes identified and the cultivars were as follows: Lrl: Karl, Mit, Newton, and Thunderbird; Lr3: Brule, Hail, Karl, Redland, and Pioneer 2180; Lrl0; Arapahoe, Karl, Mit, Sandy, TAM 105, and TAM 106; Lrl4a: Hail, Larned, Pioneer 2157, Pioneer 2163, Pioneer 2172, Pioneer 2180, Vona and Victory; Lrl6: Arapahoe, Brule, and Redland; Lr24: Abilene, Arapahoe, Cimmaron, Collin. Siouxland, Thunderbird, and TAM 200; and Lr26: Siouxland. No genes for resistance were detected in ‘Agseco 7846’ and ‘Agseco 785Y’, ‘Chisholm’, ‘Eagle’, and ‘TAM 107’. Fourteen of the 16 genes were postulated as being present in the parental lines. Lr24, Lr3, Lrl, and Lr2a occurred with the greatest frequent, followed by Lr26, Lrl0, Lrl4a, Lrl6,Lr9, Lrl7, Lr3kn, Lrl8, Lr30, and Lrll. In combination, only Lr9 and Lr24, and Lr9 and Lrl6 of these known genes presently provide resistance to leaf rust in the seedling growth stage in North America. However, the additional incorporation of Lr3ka, Lrl7, and Lr30 would provide added protection.