Abstract:

【Objective】 Xinong 1163-4 is a wheat line with high resistance to wheat leaf rust, stripe rust and powdery mildew. Identification of new leaf rust resistance gene and its closely linked molecular markers in Xinong 1163-4 will be of benefit to the use of the resistance gene and breeding new resistant cultivars. 【Method】 F1 and F2 populations from the cross Xinong 1163-4/Thatcher were inoculated with the prevalent Chinese pathotype THTT in a greenhouse. A total of 1 273 SSR primers were used to test the parents and resistant and susceptible bulks. 【Result】 Xinong 1163-4 gave low infection types to most of the Chinese current leaf rust pathotypes. Three SSR markers (Xbarc8, Xgwm582 and Xwmc269) and one STS marker (ω-secali/Glu-B3) on chromosome 1B were polymorphic between the two parents as well as resistant and susceptible bulks. The resulted four polymorphic markers were used for genotyping F2 population. Results indicated that Xinong 1163-4 carries a single dominant resistance gene, temporarily designated LrXi, located on 1BL and closely linked to SSR loci Xgwm582 and Xbarc8, with genetic distances of 2.3 and 3.2 cM, respectively. 【Conclusion】 LrXi was located on 1BL and its seedling reaction pattern was different from all known leaf rust resistance genes on 1B. The discovery of LrXi will be beneficial to enrich gene resources of wheat leaf rust resistance in China and lay a foundation for breeding cultivars with durable leaf rust resistance.

Key words: wheat leaf rust')">wheat leaf rust, resistance gene, SSR, molecular mapping