Identification of Rust Resistance Genes in Wheat (Triticum aestivum L.) Using Molecular Markers and Host-Pathogen Interaction Tests

The leaf rust (Puccinia triticina f. sp. tritici), stripe rust (Puccinia striiformis f. sp. tritici), and stem rust (Puccinia graminis f. sp. tritici) are major fungal constraints affecting wheat production worldwide. Identifying and deploying wheat varieties with diverse resistance are the best ways to manage all the rusts. Therefore, a continuous search goes on to identify diverse germplasm with effective rust resistance that expresses at different stages of plant growth (seedling and adult plant). A set of 22 rust resistant wheat genotypes and 4 checks (controls), viz., Avocet-Yr10, Avocet -Yr15, Agra Local, and respective positive checks were studied for characterising rust resistance genes using host-pathogen interactions complemented by molecular markers. Among 22 elite genotypes, 05 genotypes amplified 191 bp fragment with marker PSY1E1, confirmed the presence of gene Lr19/Sr25. These genotypes also expressed resistance to most virulent leaf rust pathotypes, 77-5 and 77-9 in host-pathogen interaction test (HPI). Seven genotypes showed the presence of Lr34/Yr18/Sr57/Pm38/Ltn1 in homozygous state, whereas G4 showed its presence in heterozygous condition. Among 22 genotypes, 16 genotypes possessed Yr10. Five genotypes (22.7%) exhibited two gene combinations, Lr19/Sr25, and Yr10 as revealed through the detection of 191 bp fragment with marker PSY1E1 and 260 bp fragment with co-dominantly inherited microsatellite marker Xpsp3000, respectively. All five genotypes (G2, G3, G8, G9, and G18) also expressed brown glumes controlled by the gene Rg1 tightly linked to Yr10 on the 1BS chromosome. Broad spectrum rust resistance present in these lines in good agronomic backgrounds could be used as potent genetic donors for diverse and durable rust resistance breeding programmes in wheat.