Molecular identification of yellow rust resistance genes in some wheat and triticale cultivars and their resistance to Puccinia striiformis f.sp. tritici

Yellow rust (YR), caused by Puccinia striiformis f.sp. tritici (Pst), is a global threat to wheat production. In this study the response of 46 wheat and triticale cultivars to Pst at the adult plant stage (APS) was evaluated during two successive growing seasons at Sulaimania, Iraq. Also, we used a molecular analysis to find the yellow rust resistance (Yr) genes present in the individual cultivars. The results revealed large differences in the response to Pst between the cultivars. Most of the cultivars were susceptible to YR; the mean coefficients of infection (CI) varied from 0.23 in cv. Sarah to 83.33 in Hsad. High resistance levels were found in Al-Wand, Kalar 1, Rezan, and Sarahat APS, while Al-Rashid, Charmo, Faris 1, Maaroof, Rabiea, and Iratom displayed moderate resistance. The level of Yellow rust infection was higher in 2023 than in 2022 in most tested cultivars. Molecular analysis revealed the highest number of Yr genes (Yr2, Yr5, Yr7, Yr9, Yrvav, Yr15, Yr24, Yr26, and Yr32) in the cv. Al-Wand, followed by Sulaimani 2 with eight Yr genes (Yr2, Yr5, Yr7, Yr9, Yr15, Yr24, Yr26, and Yr32). Only one Yr gene was found in Iratom and Tamuz 3. Yr2 was the most frequently identified gene, present in the majority of tested cultivars (87%), followed by Yr7 (76%) and Yr9 (74%), respectively.