| Wheat is one of the earliest crops to be domesticated and it also is the most important food crop worldwide. In China wheat is also a very important crop in agriculture, which is the second only following rice. Thus, wheat plays a key role on developing economy and sustaining society stability and prosperity. In order to increase wheat yield and improve quality, breeders are trying their best to breed varieties tolerant to biotic and abiotic stress. Stripe rust, caused by Puccinia striiformis, is the most important disease of wheat (Triticum aestivam L em Thell) worldwide. The best method to control stripe rust is to develop new cultivars carried resistance genes. However, it is a common view that genetic basis of wheat resistance to current prevailing stripe rust strains is very narrow and it has limited the wheat production in our country. So it is very important to find new resistant genes to stipe rust. Many studies have been proved that the local wheat varieties are rich and valuable resistance gene pool to stripe rust and have large exploited potential for wheat resistance breeding. The purpose of this study is to search for and locate the new genes for resistance to strip rust from Chinese wheat cultivars and local lines. The results are given as follows:1 Resistance response of parents and Fj's plants27 parents and 51 FI populations are screened with seven current prevailing stripe rust strains (CY30,CY31,CY32, HIII,HIV,S4 and S14). The different infection types are recorded when control material Chinese Spring and MY11 are infected completely according to the standard classification system with 6 scales from 0 to 4: 0 representing for no visible symptoms, 0; for necrotic, and 1,2,3,4 for high resistance, resistance, high susceptibility and full susceptibility, respectively. Resistance response of parents show that cultivars (R25,R57 and R59) and lines(Xingkang5, 4285, AIMS, AIM6, AIM9 and Wen-1) are immune, iso-immune or highly resistant to stripe rust while lines (Neixiangl88, Annong91168, Shan253, Lu955159, BeiZ76, Yanfu188, Wenmai6, Shu3110, Huaiying9628, Yumai47, Yumai62, Gaochen8901 and Chinese Spring) are highly susceptible or fully susceptible to stripe rust. Moreover, F1 population of AIM5, AIM6, Xingkang5 and Wen-1 treated as resistant parents exhibit immune, iso-immune or highly resistant to stripe rust and FI population of R25 and R57 used as resistant parentsexhibit susceptible or fully susceptible.2 Microsatellite loci tagging the resistant gene in wheat line aim 6In the study twenty four DNA samples, including two parents (AIM6 and BeiZ76), thirteen FZ resistant plants and eight ?2 susceptible ones, one mixture of resistant plants and one mixture of susceptible plants, were employed. Only two primer pairs (Xgwm410 and Xgwm374) out of two hundred and eighteen microsatellite primer pairs were screened to show polymorphic DNA fragments between the resistant and susceptible plants. The primer Xgwm410 at 2B chromosome amplified polymorphic amplicons Xgwm410/391 and Xgwm410/no-amplicons, which are highly consistent with the segregation of resistance in crosses between Aim 6 and it's susceptible parents. This result shows that Xgwm410 is linked to the dominant gene resistant to strip rust in wheat line Aim 6. While the polymorphism DNA fragments amplified by Xgwm374 are Xgwm374/351 for the resistant gene in Aim 6 and Xgwm374/379 for other susceptibility allele, respectively. The results indicated that the primer Xgwm410 and Xgwm374 are linked with the gene resistant to strip rust in wheat line Aim 6.3 The new gene for resistance to strip rust ,Yr34, and its Genetic mapA mono-dominant gene in wheat lines AIMS, AIM6, XingkangS, R88 and Wen-1 for resistance to current prevailing stripe rust strains (CY30, CY31,CY32, HIII,HIV,S4 and S14) at seedling and adult stages was demonstrated by resistance test and genetic analysis. The rsults indicated that the locus of microsatellite primer Xgwm410 is the directional marker of the gene because no genetic exchange was detected in al...
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