Heredity Research On Wheat Landraces With Powdery Mildew Resistance In Shaanxi

Powdery mildew,caused by Erysiphe graminis f.sp.tritici, is one of the devastating diseases in wheat (Triticum aestivum L.em Thell.),and using resistant cultivar is the most economical,effective and environmentally safe way to control this disease.Molecular markers tightly linked to resistance genes not only facilitates the identification and mapping of resistance genes,but also can be used for markers-assisted selection (MAS) of resistant lines in breeding programs.MAS greatly enhances the opportunity for gene pyramiding and progress breeding of resistance.China have abundance of wheat landrace resistance resources,they possessed a great variety of types,prematurity,good adverse resistance,extensive adaptabilityand so on.In this paper, powdery mildew resistance, gene orientation, genetic diversity, high-molecular-weight glutenin subunit(HMW-GS) and agronomic character are applied to study on 8 wheat landraces in Shaanxi province. The results obtained are as follows:The wheat landraces, Yinshanxiaobaimai, Mangmai, Aiganmangmai, Baihulu, Dahongtou, Hongyoumai, Hongmai, had been identified as highly resistant materials to under inoculated conditions by guanzhong prevalent race over three years in Shaanxi province.The inheritance of resistance to powdery mildew in the 7 varieties was studied by crossing them with susceptible varieties respectively. The data on powdery mildew resistance in F1 and F2 generations showed that Yinshanxiaobaimai ,Mangmai, Aiganmangmai, Hongyoumai, Hongmai involved three recessive and resistant genes, Baihulu involved one recessive and resistant gene, and Dahongtou involved two complementary dominant genes. It was supposed that they were new gene(s) for resisitance to powdery mildew originated from China. It was necessary to further study their relationships and exloit native resistance resources.Powdey resistance identification and genetic analysis of Laobaimai wheat lanrace showed that Laobaimai resisted powdery mildew both at the seedling and adult stages and had two recessive resistance genes ,one of then was testified to link to microsatellite molecular maker WMS314, so we concluded the gene was located on chromosome 3D in the beginning and it was a new recessive and resistant gene of powdey mildew.Compared wheat landrace with cultivars by SSR showed that the genetic diversity of 8 wheat landraces were high to 4 cultivars,by improving the landrace could release the problem of cultivars'genetic basis.Through selecting 178 pairs of SSR primers by BSA,57 pairs of primers were detected out polymorphism microsatellite DNA between parents of Baihulu and Dahongtou,the frequency of polymorphism was 32.0%,but none of them was amplificated different DNA between bulks.The result preliminary indicated that the resisitance genes of powdery mildew and 57 SSR primers were random isolation or genetic distances were far.Analysis of the high molecular weight-glutenin subunits from 8 powdey mildew resistant wheat landraces by SDS-PAGE showed that the subunits kind of them were single ,lacking of high quality subunit ,and genectic basis of milling qualities were narrow.There were lots of disadvantages through comprehensive analysis of the agronomic character and disease resistance in 8 wheat landraces,such as long culm,little guain,low1000 grain weight,but better in disease resistance.We could adopt multi-approach and multi-direction to creat excellent bridge-materials for a firmly foundation in powdey mildew resistant breeding.