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Leaf rust caused by Puccinia triticina Eriks. (Pt) is one of the most devastating fungal pathogens affecting wheat (Triticum aestivum L.) production worldwide. Deployment of resistant cultivars is the most environmentally friendly approach to control the disease. In this study, thirty-seven wheat lines from the Hubei and Shaanxi provinces in China were evaluated for seedling resistance in the greenhouse using eighteen Pt races. These lines were also tested for slow rusting resistance in the field in the 2014 to 2018 growing seasons. Eleven molecular markers closely associated with known Lr genes were used as part of the postulation process. Seven known Lr genes, 1, 13, 18, 14a, 26, 34 and 46 either singly or in combination were postulated in twenty-five cultivars. Lr1 and Lr26 were the most commonly identified genes detected in thirteen and ten cultivars, respectively. Lr13 and Lr46 were each found in four and five cultivars. Lr34 was present in three cultivars. Lr18 and Lr14a were identified in cultivar Xi'nong 538. Six cultivars displayed slow rusting resistance in the field tests. The resistant cultivars identified in the present study can be used as resistance parents in crosses aimed at pyramiding and the deployment of leaf rust resistance genes in China. [ABSTRACT FROM AUTHOR]

Common wheat (Triticum aestivum L.) is the major crop cultivated in Xinjiang and Anhui provinces of China. The climate in these two provinces is favourable for wheat leaf rust (Puccinia triticina) (Pt) infection. Here, we demonstrate a detailed investigation on the leaf rust resistance of 60 major wheat cultivars cultivated in these two regions. A mixture of high virulent Pt races (THTT, THTS, THTQ and PHPS) were used to phenotype all the collected wheat cultivars at an adult plant stage. Phenotypic disease severity (FDS) and the area under the disease progress curve (AUDPC) for each of these wheat cultivars was calculated. Among all the tested wheat cultivars, three cultivars (Xindong20, Xindong 29 and 99AR142-1) with the lowest FDS and AUDPC may carry major resistance genes. Twenty-seven cultivars (45% of the total tested ones) showed a relatively lower resistance with an average of 12.52% FDS and 126.3 AUDPC. Minor resistance or slow rusting genes may be present in this group of cultivars. Molecular markers for the leaf rust resistance genes Lr1, Lr9, Lr19, Lr24, Lr26 and Lr34 were further used for genotypic screening. Lr1, Lr19, Lr26 and Lr34 were detected in 19 (31.7%), 1 (1.7%), 12 (20%) and 6 (10%) wheat cultivars, respectively. Neither Lr9 nor Lr24 could be detected in any of the tested cultivars. These results will greatly improve wheat molecular breeding for leaf rust resistance in these areas. [ABSTRACT FROM AUTHOR]