Evaluation and identification of stem rust resistance genes , , , , and in wheat lines from Gansu Province in China.

Wheat stem rust, caused by f. sp. , severely affects wheat production, but it has been effectively controlled in China since the 1970s. However, the appearance and spread of wheat stem rust races Ug99 (TTKSK, virulence to ), TKTTF (virulence to ) and TTTTF (virulence to the cultivars carrying and ) have received attention. It is important to clarify the effectiveness of resistance genes in a timely manner, especially for the purpose of using new resistance genes in wheat cultivars for durable-resistance. However, little is known about the stem rust resistance genes present in widely used wheat cultivars from Gansu. This study aimed to determine the resistance level at the seedling stage of the main wheat cultivars in Gansu Province. A secondary objective was to assess the prevalence of , , , , , and using molecular markers. The results of the present study indicated that 38 (50.7%) wheat varieties displayed resistance to all the tested races of f. sp. The molecular marker analysis showed that 13 out of 75 major wheat cultivars likely carried ; 25 wheat cultivars likely carried ; and nine wheat cultivars likely carried . No cultivar was found to have and , as expected. Surprisingly, no wheat cultivars carried . The wheat lines with known stem rust resistance genes could be used as donor parent for further breeding programs.