| Stripe rust, caused by Puccinia striiformis f.sp. tritici, is one of the most serious diseases of wheat in the worldwide. China is the largest epidemic region in the world and severe losses in grain yield have been reported. At present, the simplicity and homology of stripe rust resistance background in commercial wheat cultivars have not changed all though a lot of cultivars are used in wheat production. Identification and excavation new stripe rust resistance genes is an important method for controlling stripe rust. Geneticists and plant breeders pay more attention to wild relatives and elite cultivars carring durable resistance in order to search new resistant germplasms.The genitic mechanism of 5 variaties derived from alien resistant resources and Gaby to stripe rust were studied in this research,The results are as follow:1. Genetic analysis of Zhongliang 88375 indicated that resistance to race CYR31 was controlled by a single dominant gene, temporarily designated as Yr88375. To molecular map Yr88375, a F2 segregating population consisted of 163 individuals was constructed on the basis of the hybridization between Zhongliang 88375 and a susceptible wheat line Mingxian169.On the one hand, six SSR markers,Xgwm335, Xwmc289, Xwmc810, Xgdm116, Xbarc59 and Xwmc783 linked to Yr88375 , as they were all located on chromosome 5BL , Yr88375 was also located on that chromosome arm, closely linked to Xgdm116 and Xwmc810 with genetic distances of 3.1 and 3.9 cM, respectively. The furthest marker Xwmc783 was 13.5 cM toYr88375. On the other hand, the resistance gene Yr88375 was located on chromosome 5B by RGA tagging and the 21 Chinses Spring nulli-tetrasomic. Hence, pedigree analysis of Zhongliang 88375 combined with SSR markers support on the conclusion that the highly resistance gene Yr88375 derived from Elytrigia intermedium, is a novel gene for resistance to stripe rust in wheat.2. To identify and tag new resistance genes to stripe rust in a wheat cultivar Zhongliang 22, Genetic analysis indicated that Zhongliang 22 contains three to five resistance genes and one dominant nucleic gene (temporarily designated as Yrzhong22) and one recessive CYR31 toplasmic gene conditioned stripe rust rust resistance in Zhongliang 22 inoculated with CYR31.Using SSR markers combined with bulked segregation analysis (BSA) revealed that four SSR markers located on chromosome 5BL were linked to Yrzhong22. The genetic distances between Yrzhong22 and its nearest markers Xwmc810 and Xgdm116 were 2.7 cM and 4.4 cM, respectively. Yrzhong22 is probably a novel resistance gene to wheat stripe rust donated from Elytrigia intermedium on the basis of pedigree analysis and molecular result.3. Genetic analysis of translocation line M8657-1 indicated that resistance gene conferring to CYR30 was controlled by one recessive gene, resistance genes conferring to CYR31 controlled by two dominant karyoplasms genes (complementary); resistance gene conferring to SU11-4 was controlled by one dominant gene temporarily designated as YrElm1,resistance gene conferring to SU11-11 was controlled by one single recessive karyoplasms gene. Through SSR and analysis with resistance pool and susceptible pool, Three SSR markers on the short arm of chromosome 2A were found linked to YrElm1. The SSR markers were Xgwm636,Xwmc522 and Xwmc453 and their genetic distances from YrElm1 were 8.9 cM,5.9 cM and 10.3 cM, respectively. At present, stripe rust resistance gene Yr17 have been located to chromosome 2AS.Based on the origin of resistance genes and seedling test pattern, The result showed that YrElm1 is probably a new stripe rust resistance gene.4. Inheritance of translocation line M853-2 by artificial inoculation with different races at seedlings. The results showed resistance gene conferring to race CYR29 was controlled by two dominant and one recessive genes independently, the resistance to race CYR30 was controlled by two dominant and one recessive genes (they are karyplasms genes) and three recessive cytoplasmic genes, and the resistance gene to CYR31 was controlled by two dominant complement genes, and the resistance to SU11-4 was controlled by one dominant and one recessive karyplasms gene and two dominant cytoplasmic genes ,while the resistance to the race SU11-11 was controlled by one dominant gene, temporarily designated as YrElm2. To develop molecular markers for YrElm2, bulk segregation analysis combined with 320 SSR markers were used for, one SSR marker, Xgwm495 on the 4BL was associated with YrElm2. The genetic distance between Xgwm495 and YrElm2 was about 7.6cM. YrElm2 was located on the 4BL. By comparision with other genes on 4B chromosome, we could conclude that YrElm2 is probably a novel gene origin from Elymus mo11is (Trin.) Hara.5. Genetic analysis of translocation line M853-4 indicated that resistance gene conferring to races CYR29,CYR30,CYR31 were all controlled by a single dominant karyoplasms gene; Resistance of M853-4 conferring to SU11-11 was controlled by one dominant and one recessive genes. A total of 320 SSR primers were used to test the parents as well as resistant and susceptible bulks. Three SSR markers on the short arm of chromosome 5A were found linked to YrElm4. The SSR markers were Xwmc654,Xgwm304 and Xgwm129,and their genetic distances from YrElm4 were 5.8 cM,7.1 cM and 10.3 cM,respectively.6. It had proved that wheat cultivar Gaby is an important resistant resource to stripe rust. Genetic analysis of Gaby indicated that resistance gene conferring to CYR29 was controlled by one dominant gene temporarily designated as YrGaby. To CYR32, Gaby has two genes resisted(they possibly are either recessive or present addition effect) when it is female parent ,and it possibly has one dominant and two recessive genes when it is male parent. To SU11-11 strain, Gaby has three genes (two of them present additive effect) when it is female parent, and has one dominant and one recessive genes when it is male parent .Bulk segregation analysis combined with 320 SSR markers were used for, Four SSR markers on the long arm of chromeosome4A were found linked to YrGaby ,they were Xgwm397,Xwmc161,Xwmc698and Xwmc760,and their genetic distances from YrGaby were 13.8 cM,8.6 cM,5.1 cM and 16.6 cM,respectively. In addition, the resistance gene YrGaby was located on chromosome 4A by RGA tagging and the 21 Chinses Spring nulli-tetrasomic, and two RGA markers were linked to YrGaby with genetic distance was 4.2 cM and 9.1 cM, repectively. |
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