| Stripe rust or yellow rust (YR) caused by Puccinia striiformis West. f. sp. tritici Eriks. (Pst) is an important disease of wheat worldwide. The wheat growing region in the middle and lower reaches of the Yangtze River is one of the main wheat production areas and the important commodity grain base in China. It is also a severe YR endemic region in China. Evaluation of the resistance to YR for wheat varieties (lines) and characterization the corresponding resistance genes in the region is of great significance for control this disease. However, no information is available regarding YR resistance and the genes in wheat breeding lines in this region. This study collected 103 wheat accessions comprised of 34 elite commercial varieties and 69 advanced breeding lines from this region including Jiangsu, Anhui, and Hubei from 2019 to 2021. In 2021, adult plant resistance (APR) was evaluated in the artificial infection nursery of Yangling with mixed races (CYR32, V26-lab) in Shaanxi and the naturally induced disease nursery of Jiangyou in Sichuan; the current prominent Pst races CYR32 and V26-lab were used for seedling test. Molecular detection included 11 all-stage resistance (ASR) genes (Yr5a, Yr5b, Yr6, Yr7, Yr9, Yr15, Yr26, Yr28, Yr81, YrZH84, and YrAS1676) and 5 APR genes (Yr18, Yr30, Yr78, Yr86, and YrLT26). APR was conferred by 23 out of the 34 elite varieties in both Yangling and Jiangyou. Among 69 advanced lines, 11 and 13 lines conferred resistance to CYR32 and V26-lab at seedling stage, respectively, while only 2 lines showed near immunity to both CYR32 and V26-lab. Cluster analysis of disease severity for wheat lines indicated that there were 44 lines and 25 lines conferring APR in Yangling and Jiangyou, respectively, and only 17 lines displayed stable resistance in both environments. Molecular detection showed that the tested lines may carry with Yr5b, Yr6, Yr7, Yr9, Yr30, Yr78, Yr81, Yr86, YrZH84, YrLT26, YrAS1676 ,but Yr5a, Yr15, Yr18, Yr26, Yr28 were not found in lines. Further, only Yr6, Yr81, and YrLT26 and the combination of Yr78, Yr81, Yr86, and YrAS1676 were significantly associated with YR resistance. Compared with the varieties released before 2010, the current wheat breeding lines possessed higher resistance indicating a significant improvement in resistance breeding. Moreover, there is a noticeable trend towards diversification in the utilization of resistance genes. |
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