Molecular Marker-Assisted Selection For Wheat Disease Resistance

In this research , by using of genomic in situ hybridization (GISH) , random amplified polymorphism DNA (RAPD) technology and three specific SCAR molecular markers, the author analyzed wheat hybrid generations carrying the desired genes that were resistant to take-all, BYDV and/or powdery mildew, and developed some alien chromosome addition and translocation lines that were important in breeding practice, and some specific molecular markers that could be applied in marker-assisted selection.Breeding resistant or immune cultivars was the most economical and efficient way to control wheat take-all disease. In this study, the author used GISH technology to analyze the material that was resistant to take-all in test, and got three chromosome arm addition lines that carried the resistance genes derived from the amphiploid of Triticum-Haynaldia. The above arm addition lines and their resistant and sensitive parents were analyzed by RAPD method and two specific molecular markers that were tightly linked to resistant gene were obtained.Amount studies on BYDV resistant gene Bdv2 on 7X of Thinopyrum intermedium were reported.Another resistance gene on 2Ai-2 of chromosome group 2 of Thinopyrum intermedium from amphiploid Zhong 4 Awnless had better resistance to GPV and GAV serotype of BYDV that were prevail in China ,so it's important to develop the chromosome translocation lines of Zhong 4 Awnless. In this research, the author utilized RAPD method to analyze 2Ai-2 chromosome or arm of addition or substitution lines of Zhong 4 Awnless . Two RAPD molecular markers located on different arms of 2Ai-2 chromosome from Thinopyrum intermedium were selected and the generations of the hybrid generation derived from Zhong 4 Awnless and wheat were analyzed. Two chromosome translocation lines were screened for wheat breeding program to control BYDV.It's important to breed varieties(lines) with multiple disease resistance genes, but it's difficult for traditional breeding ways to identify two or more resistant characteristics quickly and immediately at the same time. Marker-assisted selection technology made this issue simple and feasible. In this study, the author used a molecular marker SCW-37 that was specific for BYDV resistant gene Bdv2, and two molecular markers that were specific for powdery mildew resistant genes Pm13 and Pm21 to analyze 54 candidate plants. As a result, 1 plant pyramided Pm13+Pm21+ Bdv2 resistant genes, 1 plant pyramided Pm13+ Bdv2, 11 plants pyramided Pm21+ Bdvi, were selected for further breeding practice.