SCAR Marker Development And Application Of Powdery Mildew Resistance Gene In Wheat Lines2-26

Wheat powdery mildew caused by Erysiphe graminis f.sp.tritici, is one of the main wheat diseases. It can happen in the whole growth period of wheat. When wheat is infected by powdery mildew, the photosynthesis of wheat will be seriously affected, resulting in reducing of grains per ear and thousand kernel weight, and lower yield, or even no any harvest. The serious tendency was found for powdery mildew infected in wheat production worldwide. With resistance genes applied rapidly overcomed by Blumeria graminis, the powdery mildew resistance genes which have been using currently are far from meeting the needs of the disease resistance breeding, and it’ s urgent to develop new powdery mildew resistance genes, to speed up the powdery mildew genes’ s application research. The related genus of wheat are the huge gene pool for wheat genetic improvement. Exploring new resistance genes through wheat distant crossing or other methods have greatly importance in powdery mildew resistance breeding.Genetic analysis of powdery mildew resistance were carried out fora wheat stable line2-26derived from the hybrid progeny between common wheat and Dasypyrum villosum with powdery mildew resistanceby tranditional genetic anylysis, molecular markers and C-banding.The main results are summerized as follows:1. Genetic analysis of powdery mildew disease resistance indicated that the wheat line2-26and its F1population of2-26×Miangyang11(MY11is a cultivar which is seriously susceptible powdery mildew) were immune to powdery mildew, and the segregant ratio for resistant and susceptible plants of F2population showed good fit into3:1. These results showed there is a single dominant gene, temporarily named Pm2-26, which is responsible for the powdery mildew resistance in line2-26.2. Among340SBS primers (A-Q), there are two RAPD primers, SBSC2and SBSI20, have polymorphisms in powdery mildew resistant and susceptible parents and resistant and susceptible gene bulks. The two polymorphic RAPD primers were used for2-26X MY11F2population (including185individuals),5recombinant plants,3recombinant plants were found for SBSC2, SBSI20, respectively. Linkage analysis was conducted with the software Mapmaker3.0. Results showed SBSC2was linked to Pm2-26with the genetic distance of2.78cM, while SBSI20is1.62cM.3. RAPD markers are easily affected by environment, and the stability and repeatability are poor, a present study,we try to transfer two RAPD markers into stable SCAR markers. According to SBSI20polymorphism sequence, we successfully transformed two SCAR marker, temporarily named SCARI20-392and SCARI20.329. Using SCARI20.392and SCARI20-329to analyse the resistant and susceptible parents and resistant and susceptible gene bulks, the results show SCARI20.392and SCARI20.329could completely amplified same band with RAPD marker, and its stability and repeatability were greatly enhanced. Howerer, the SBSC2was failed to transformed into SCAR marker.4. Three specific prmers which are on the6VS of D. villosum, CINAU15.902(0.46～0.58), CINAU17.1086(0.58～1.00) and CINAU18-723(0.00～0.45) were used to analyse the resistant and susceptible parents and resistant, susceptible gene bulks and the F2population. It found that only CINAU18-723(0.00～0.45) was linked with Pm2-26, suggesting Pm2-26may locate on fragment of6VS(0-0.45). All these results inferred that Pm2-26may be a new powdery mildew resistance gene, but the real reason needed further study.5.Using SCARI20-392and CINAU18-723to analyse F2population, and using the software Mapmaker3.0, the lingkage distance of SCARI20-392and CINAU18-723with Pm2-26was1.62cM and1.08cM respecively.The linkage map was drawed by the software Mapdraw. However, the two primers were in the same side of Pm2-26.The result had no advantage in indentificaton and tracking Pm2-26, thus new linked markers are need to develop for more efeectivly selected the Pm2-26.6. Line2-26was derived the hybrid progeny of common wheat and D.villosum, the chromosome constitution of line2-26was checked by C-banding, The result indicted2-26was a T6VS/6AL.