Characterizing the Genetic Basis of Winter Wheat Rust Resistance in Southern Kazakhstan

In an effort to enhance wheat's resilience against rust diseases, our research explores the genetic underpinnings of resistance in a diverse collection of winter bread wheat accessions. Leaf rust (<i>Puccinia triticina</i>), yellow rust (<i>Puccinia striiformis</i> f. sp. <i>tritici</i>), and stem rust (<i>Puccinia graminis</i> f. sp. <i>tritici</i>) are significant threats to global wheat production. By leveraging host genetic resistance, we can improve disease management strategies. Our study evaluated 55 wheat accessions, including germplasm from Kazakhstan, from Uzbekistan, from Russia, from Kyrgyzstan, France, and CIMMYT under field conditions in southern Kazakhstan from 2022 to 2024. The results showed a robust resistance profile: 49.1% of accessions exhibited high to moderate resistance to leaf rust, 12.7% to yellow rust, and 30.9% to stem rust. Notably, ten accessions demonstrated resistance to multiple rust species, while seven showed resistance to two rusts. Twenty accessions were selected for further seedling resistance and molecular analysis. Three accessions proved resistant to six isolates of <i>P. triticina</i>, two to four isolates of <i>P. striiformis</i>, and four to five isolates of <i>P. graminis</i>. Although no genotypes were found to be universally resistant to all rust species at the seedling stage, two accessions-Bezostaya 100 (Russia) and KIZ 90 (Kazakhstan)-displayed consistent resistance to leaf and stem rust in both seedling and field evaluations. Molecular analysis revealed the presence of key resistance genes, including <i>Lr1</i>, <i>Lr3</i>, <i>Lr26</i>, <i>Lr34</i>, <i>Yr9</i>, <i>Yr18</i>, <i>Sr31</i>, <i>Sr57</i>, and the 1AL.1RS translocation. This work provides valuable insights into the genetic landscape of wheat rust resistance and contributes to the development of new wheat cultivars that can withstand these diseases, enhancing global food security.