Development Of Wheat Breeding Materials Resistant To Both Powdery Mildew And Barley Yellow Dwarf Virus And Function Of TaGW2 Gene

Powdery mildew and barley yellow dwarf virus (BYDV) are important diseases, which affect wheat production worldwide. Resent years, both diseases are simultaneously found in some areas of China and caused severy economic lost. Cultivation of wheat breeds which can resistant to many kinds of diseases at the same time is tyhe best way to solve this problem. High yield is the final target of wheat breeding, thousand kernel weight, Kernel number of a whole plant, and tiller number are the most important factors of wheat yield. TaGW2 gene is one of the most important gene in wheat which can regulate the seed shape, but how do TaGW2 gene executive it’s function is not really clear. This research contain two parts, the first part is development of a new wheat material resistant to both barley yellow dwarf virus and powdery mildew, the second part is the function research of TaGW2 gene. By that we can obtain some wheat materials with high resistance, and materials which have big and heavy seeds. The main results is listed as follows:(1)A wheat-Thinopyrum intermedium translocation YW642, containing BYDV resistance gene Bdv2, and a wheat line CB037, containing powdery mildew resistance gene Pm21, had been used to cross and backcross in this study. And finally, some wheat materials resistant to both barley yellow dwarf virus and powdery mildew have been obtained. Through the disease resistance tests and molecular marker-assisted selection,48 F1 plants,22 BC1 plants and 51 F2 plants which contain both Bdv2 and Pm21 genes were obtained. Agronomic trait assays displayed that those resistant plants possessing both Pm21 and Bdv2 genes were better than susceptible plants and the parents plants following inoculation with the pathogens. Thus, these resistant plants developed in the study can be used as good germplasm resources for wheat breeding with resistance to powdery mildew and BYDV.(2)RNA interference technology has been adopted in this research.21 wheat plants with TaGW2 gene silencing carrier have been obtained by particle bombardment. Quantitative analysis, seeds length,width and thickness measurement, life period, tiller number, plant height, kernel number of a whole plant, kernel weight of a whole plant, thousand kernel weight analysis have been done. Results show that TaGW2 gene not only can regulate the seed length but also can regulate seed width, and its regulation effect is negatively. The seed length and width of wheat lines with silencing carrier is gained that receptor Shi4185, but seed thickness and length-to-width ratio have no significant change, kernel weight of a whole plant and thousand kernel weight analysis are both better than receptor Shi4185, so silencing of TaGW2 gene can enhance the yield of wheat.Brief summery:both the materials of resistant to barley yellow dwarf virus and powdery mildew and materials contain TaGW2-RNAi carriers improved the agronomic traits of wheat and can be adopted into wheat’s genomic improvement. Both materials are valued to breeding and screening to get lines which can inheritance steadily, then used as resources to improve resistance or seeds traits. Furthermore, these two material can be hybridized to obtain materials which combine BYDV resistance, powdery mildew resistance and big seeds.