| Powdery mildew, caused by Blumeria graminis f. sp. tritici, is one of the devastating diseases in most wheat-growing areas worldwide. Breeding for varieties with resistance alleles has been proved to be the most economical, safe and effective way for controlling the disease and ensuring the stable increasing-production of wheat. Diversification of sources of resistance and development of resistance germplasm have been suggested as a remedy of the problem, provided that an adequate number of resistance genes available. SSR(Microsatellite) marker has been proven to be a powerful tool in gene discovery. In the present study , the development of germplasm resistant to powdery mildew, chromosome location and molecular markers of germplasm were done in order to provide new germplasm resistant to powedry mildew for breeder and find new gene resistant to powdery mildew. The results are described as follows:Triticum carthlicum-Aegilops umbellulata amphidiploid Am9 resistant to powedry mildew, Triticum dicoccoides accession AS846 and wheat-Haynaldia villosa translocation line 92R149 resistant to powdery mildew and stripe rust as resistance genes donor, in the progeny of combination'Abbondanza 5B euploid/AS846','Shaan160/Am9//Shaan160'and'92R149/Xian87(30)//Xiaoyan No.6', N9134 and N9628-2 resistant to powdery mildew, and N95175 resistant to both powedry mildew and stripe rust with better agronomic traits were bred. Three germplasm were stable in morphology. Their chromosome numbers in the root tips and chromosome configuration at PMC MI were 2n=44 and 2n=22Ⅱ. F1 progeny between N9134 and four highly susceptible common wheat cultivars were highly resistant to powdery mildew, the ratio of the resistant and susceptible plants in F2 progeny fitted the expected 3 to 1. All of F1 progeny between a set of highly susceptible common wheat nullisomic lines or monosomic lines and N9134 were highly resistant to powdery mildew, the ratio of the resistant and susceptible plants of (Abbondanza 5BM×N9134)F2 progeny deviated from the expected 3 to 1, and F2 progeny of the other 20 crosses fitted the expected 3 to 1. The results indicated that the powdery mildew resistance of N9134 at seedling stage was controlled by a single dominant gene located on chromosome 5B. Segregating F2 progenies of the cross Shaan160×N9134 with 92 plants and Shaanyou225× N9134 with 84 plants were used for SSR analysis by 66 wheat microsatellite primer pairs (17 microsatellite primer pairs assiged to 5B ). Xgwm67 could generate polymorphic DNA fragments between the resistant and susceptible plants DNA pools. After evaluating the polymorphic markers in the segregating populations, Xgwm67 was found to be linked to the resistance gene with the estimated genetic distance of 20.6 cM. The results indicated that the resistance gene was located on chromosome 5B, which was in accodance with the anueploid analysis results. The analysis results of Xgwm67 in CSN5AT5D, CSN5BT5D, CSN5DT5A, CSDt5AL, CSDt5BL and CSDt5DL indicated that the resistance gene might be located on 5BL. The analysis results of Xgwm67 in N9134 , T. dicoccoides accession AS846 and common wheat cultivar Abbondanza showed the resistance gene was derived from T.dicoccoides accession AS846. The gene may be a novel gene different from the reported gene resistant to powdery mildew and is temporarily designated PmAS846. In addition, the analysis results of HMW-GS and SSR of N9134, AS846 and Abbondanza showed that 1B, 2A and 5B chromation of AS846 had been transferred to N9134 and concluded that there were at least five translocation breakpoints in 5B of N9134.F1 progeny between N9628-2 and three highly susceptible common wheat cultivars were highly resistant to powdery mildew, the ratio of the resistant and susceptible plants in F2 progeny fitted the expected 3 to 1. All of F1 generation between a set of highly susceptible common wheat nullisomic lines or monosomic lines and N9628-2 were highly resistant to powdery mildew, the ratio of the resistant and susceptible plants of (Abbondanza 6AN×N9628-2)F2 progeny deviated from the expected 3 to 1, and F2 progeny of the other 20 crosses fitted the expected 3 to 1. The results indicated that the powdery mildew resistance of N9628-2 at seedling stage was controlled by a single dominant gene located on chromosome 6A. Segregating F2 progenies of N9628-2×Shaan160 with 142 plants were used for SSR analysis by 110 wheat microsatellite primer pairs (30 microsatellite primer pairs assiged to 6A ). Xwmc553 and Xwmc684 on chromosome 6A generated polymorphic DNA fragments between the resistant and susceptible pools. After evaluating the polymorphic markers in the segregating populations, Xwmc553 and Xwmc684 were found to be linked to the resistance gene with the estimated genetic distance of 10.99 cM and 7.43 cM, respectively. The results indicated that the resistance gene was located on chromosome 6A, which was in accodance with the anueploid analysis results.The analysis results of Xwmc553 and Xwmc684 in CSN6AT6B, CSN6BT6A, CSN6DT6A, CSDt6BL, CSDt6BS, CSDt6AL, CSDt6AS, CSDt6DL and CSDt6DS indicated that the resistance gene located on 6AS. The analysis results of Xwmc553 and Xwmc684 in N9628, common wheat cultivar Shaan160, Am9, T.carthlicum accession PS5, Ae.umbellulata accession Y39 and shoewd the resistance gene was probably derived from Y39.The resistance gene in N9628-2 was probably a new gene different from the reported resistance genes and is temporarily designated PmY39-2.F1 progeny between N95175 and four highly susceptible common wheat cultivars were highly resistant to powdery mildew, the ratio of the resistant and susceptible plants in F2 progeny fitted the expected 3 to 1. All of F1 generation between a set of highly susceptible common wheat nullisomic lines or monosomic lines and N95175 were highly resistant to powdery mildew, the ratio of the resistant and susceptible plants in (Abbondanza 6AN×N95175)F2 progeny deviated from the expected 3 to 1, and F2 progeny of the other 20 crosses fitted the expected 3 to 1. The results indicated that the powdery mildew resistance of N95175 at seedling stage was controlled by a single dominant gene located on chromosome 6A. N95175, wheat -H.villosa translocation line 92R149, common wheat 92R149 and Xiaoyan No. 6 were analysis by SCAR(sequence characterized amplified region) markers of Pm21 and microsatellite markers Xgwm11 and Xgwm18 tightly linked with Yr26. The specific SCAR bands of Pm21 was amplified in N95175 and 92R149 resistant to powdery mildew, but none was amplified in Xian87(30) and Xiaoyan No.6 susceptible to powdery mildew. The amplified products of N95175 using Xgwm11 and Xgwm18 was the same bands as 92R149 resistant to stripe rust, but it was different with two parents susceptible to stripe rust. The results showed that the gene resistant to powdery mildew in N95175 was Pm21, and the gene resistant to stripe rust in N95175 was Yr26.
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