Seedling and adult plant stem rust (Puccinia graminis f. sp. tritici) resistance genes in CIMMYT wheat (Triticum aestivum L.) genotypes

Stem rust (Puccinia graminis f. sp. tritici) virulence on multiple genes has resulted in severe yield losses from wheat (Triticum aestivum L.) cultivars worldwide. A study was conducted to determine (i) seedling resistance to stem rust races TTKSK, TTKST, TTKTT, TTTTF, and TRTTF; (ii) resistance to stem rust at the adult plant stage (APR); and (iii) the stem rust-resistant genes present in CIMMYT advanced wheat lines using STS, SSR, and KASP molecular markers to detect the Sr2, Sr12, Sr13, Sr22, Sr24, Sr26, Sr38, Sr57, and Sr8155B1 genes. A set of 175 CIMMYT advanced wheat lines were evaluated for seedling resistance in the greenhouse and APR in a field experiment. At the seedling stage, 23.12% of the wheat lines were resistant to all races, with infection types (ITs) ranging from “;” to “2+”. At the APR stage, 9.71% of the wheat lines were resistant, with stem rust severity and reactions of 5R to 20MS. About 15.29% of the lines were resistant both at the seedling and APR stages, with reactions of “;” to “2+”, and 5R to 40M, respectively. The lines that possessed genes Sr22 and Sr26 were resistant to all the stem rust races at the seedling stage, with IT < 3 and reactions of 5R–40MS at the adult plant stage. Wheat lines KSRON 40 (Sr22), KSRON 52 (Sr8155B1), KSRON 78 (Sr26, Sr12, Sr38), KSRON 129 (Sr22, Sr12, Sr38), and KSRON 144 (Sr13, Sr22, Sr12, Sr38) could be used as valuable genetic stock for stem rust resistance.