Identification Of Tritileymus Germplasm Line And SSR Molecular Identification Of Its Resistance Gene

Leymus mollis with good resistance to many diseases is the relative of wheat. Interestgenes of L.mollis could be transferred using medium materials Octoploid Tritileymus derivedfrom hybridization of wheat and L.mollis. In this research, inoculation assessment, physicaland cytological analysis, microsatellite marker techniques were employed in the identificationof eight Tritileymus Germplasm, which were selected from the progenies of OctoploidTritileymus×common wheat.The main results were as follows:1By methods of morphology and cytology,8Tritileymus Germplasm（Shannong0693-1，0920-1，0695-2，0699-4，1815-4，0693-2，0696-6and6343） were identified frommain agronomic and Cytological characteristics. Genomic in situ hybridization （GISH） wasused to establish the chromosome constitutions of Shannong0920-1,0695-2,0696-6and1815-4, It was primarily indicated also to be the Leymus mollis germplasm of introgressionlines or translocation line. It was proved that Shannong6343was a wheat-Leymus mollistranslocation line with a small Leymus mollis fragment. It was showed that they appearedwell agronomic charaeteristic, Powdery mildew resistance or yellow rust resistance, morespike,1000-grain weight. They will play an important role in the wheat genetic improvement.2Inoculation with powdery mildew pathogen was conducted with an aim to specify thehereditary characteristics of powdery mildew resistance gene in Tritileymus Translocationline Shannong6343. The results showed that the powdery mildew resistance ofShannong6343was controlled by a single dominant gene, which was temporarily designatedPmSn6343（t）. Various molecular markers were used to genotype the two parents and theirderived lines. Four hundred and three molecular markers of the1980SSR, EST-SSR and ESTmarkers showed polymorphisms between the two parents. Of these, Wmc658and Barc122showed good consistency between the genotype and the phenotype to mildew in the PreferredSmall Group, and they were used to screen the302F₂lines. The genetic distances between itand Wmc658and Barc122were3.4cM and5.4cM respectively, and it was presumably assigned to chromosome2AL. Authenticity of the linkage between it and molecular markershave been confirmed by progeny test of F2:3families, indicating that they were reliablemarkers linked to it.3Inoculation in the field with Yellow rust pathogen was conducted with an aim tospecify the hereditary characteristics of yellow rust resistance gene in Shannong6343×HuixianhongF2. Various molecular markers were used to genotype the two parents and theirderived lines. The results showed that the yellow rust resistance of Shannong6343wascontrolled by a single dominant gene, which was temporarily designated YrSn6343（t）. Fourhundred and three molecular markers showed polymorphisms between the two parents. Ofthese, Wmc313and gwm350showed good consistency between the genotype and thephenotype to yellow rust in the Preferred Small Group （PSG）, and they were used to screenthe208F2lines. The genetic distances between it and Wmc313and gwm350were4.8cM and15.9cM respectively, and it was presumably assigned to chromosome4AL. Authenticity ofthe linkage between it and molecular markers have been confirmed by progeny test of F2:3families, indicating that they were reliable markers linked to it.