Evaluation of Rust Resistance in the Seedling Stage of Wheat Varieties and Disease-Resistant Gene Detection in Shanxi Province, China

Stripe rust and leaf rust are major diseases affecting wheat production in the Huang-Huai winter wheat region, accurate identification of resistance in wheat cultivars, understanding the distribution of disease-resistance genes, excavate new disease-resistance genes/loci lays the foundation for the breeding and promotion of disease-resistant varieties.

We phenotyped 326 Shanxi wheat at both seedling against the prevalent Chinese Pst races CYR32 and CYR34, and Pt race PHSH. To identify more Yr/Lr genes, we also conducted molecular detection and GBTS, using a genome-wide association study (GWAS) using a wheat 16K SNP array.

Shanxi wheat seedlings demonstrate generally good resistance to stripe rust during the seedling stage, 97 cultivars such as Jinmai 919, Yunmai 766 and Linhei 199 showed good resistance to the Pst isolate CYR32 and CYR34 during the seedling stage; 15 (4.60%) cultivars such as Zhonghan 110, Zeyou 2 and Shinong 086 showed resistance to the isolate Pst isolate CYR32; 14 (4.29%) cultivars such as Jinnong 207, Jinmai 13 and Linhei 199 showed resistance to the isolate Pst isolate CYR34; wheat seedlings in Shanxi Province exhibit poor resistance to leaf rust during the seedling stage, 12 cultivars showed moderate resistance to the isolate Pt isolate PHSH. Of the 23 Yr/Lr genes assayed, a total of eleven stripe rust resistance genes/QTLs have been detected, including QYrqin.nwafu-2AL (87.42%), Yr78 (27.30%), Yr9 (24.54%), QYrsn.nwafu-3DL (15.95%), Yr75(13.19%), QYrhm.nwafu-2BC (10.73%), Yr5 (7.98%), Yr80 (2.76%), QYr.nwafu-4BL (2.15%), YrSP (1.84%) and Yr82 (1.84%), as well as seven leaf rust resistance genes, including Lr46 (28.83%), Lr1 (22.09%), Lr68 (16.87%), Lr26 (16.56%), Lr34 (11.96%), Lr13 (5.83%) and Lr37 (1.23%) were identified in wheat varieties from Shanxi province, whereas Yr15, Yr26, Lr10, Lr21 and Lr80 were not detected; for the pyramiding of multiple Yr/Lr genes, the highest proportion was the QYrqin.nwafu-2AL+QYrsn.nwafu-3DL and Lr46+Lr68 combinations. GWAS identified five loci significantly associated with stripe rust resistance, 2B, 5B and 7A may harbor novel loci associated with stripe rust resistance, simultaneously identified fourteen loci significantly associated with resistance to leaf rust disease, 1B, 4A and 5A may harbor novel loci associated with stripe rust resistance.

Shanxi wheat exhibits generally good resistance to stripe rust during the seedling stage, but overall resistance to leaf rust is poor, thirty-eight loci significantly associated with stripe rust/leaf rust resistance were mapped across 13 chromosomes, including 1B, 2B, and 3B.Preliminary analysis suggests that fourteen of these loci, including QYrs-2B, QLrs-2A and QLrs-4A may represent novel rust resistance loci.