| Wheat stripe rust, caused by (Puccinia striiformis Westend.f.sp. tritici), occurred in manycountries and regions, especially in the cooler and wetter environments and can be spread byair. The disease had repeatedly pandemic in China and caused heavy losses, is one of the mostimportant diseases in common wheat production. Through extensive research and productionpractice by researchers of stripe rust of domestic and foreign, the use of resistant cultivars isthe most economical, effective, and environmentfriendly way to reduce damage and losscaused by stripe rust. However, with the race of the stripe rust pathogen have a high degree ofvariability and plant the single disease resistant cultivars in same area for many years canaccelerate the pathogen directional selection, the resistant cultivars are likely to be susceptiblerelated to appearance and development of novel races of the stripe rust pathogen. Therefore,continue to explore and create new resistance resources, and increase the diversity of wheatresistance sources which has a great significance for sustainable control of wheat stripe rust.Guinong775was an excellent resistance resource material that composited from thedistant hybrid offspring in the wheat breeding project, after many years of planting indifferent parts of area, it is proved that still resistant to the most races of stripe rust pathogenand used as an parental material in wheat breeding program, whereas the inheritance ofresistance to stripe rust of Guinong775is still unclear. The wheat cultivar Centrum（Hussar/Konsul//Lambros）is an important resistance germplasm to stripe rust and fusariumhead blight from Germany. The agronomic traits and quality of flour are excellent and middleresistance to fusarium head blight, after many years of planting in different parts of area, it isproved that still resistant to the wheat disease.To confirm genetics resistance of new wheat germplasm Guinong775and Centrum tostripe rust, ten prevalent PST isolates were used for seedling tests to investigate the resistanceof Guinong775and Centrum. Adult stage resistance to stripe rust of Centrum evaluated atYangling and Tianshui in the field. F2plants, F3lines and BC1polulation derived from a crossbetween Guinong775/Centrum and susceptible line Avocet Susceptible (Avocet S) were usedfor seedling tests to CYR29, CYR32, the mixed races consisting of CYR29and CYR32at aratio of1:1, and CH42, the new pathogen discovered in Sichuan province which virulence to Yr26, to investigate the genetics of resistance.BSA were used for screening and separation ofmarkers linked to Guinong775, and genetic distance was calculated by F2:3population.Combine with the results of the genetic analysis and chromosomal localization, we hybridedthe Guinong775with the cultivars or single-gene lines which resistance genes located on thesame chromosome to investigate its allelism with these genes, results are as follows:1. Resistance spectra showed that Guinong775was immune or nearly immune to tenPST isolates, whereas92R137, Guinong22, Chuanmai42, Guinong22, Yr24/6*Avocet S,Yr26/6*Avocet S were susceptible to CH42. Centrum was immune or nearly immune to eightPST isolates and adult stage in the filed also had a high resisitance. The results showed thatGuinong775and Centrum had a high resistance to stripe rust and had a great value forpotential applications.2. The results of genetic resistance analysis showed that Guinong775was controlled bya single dominant gene to CYR32, it also carries a single dominant gene for resistance toCH42and they are two different race-specialized resistance genes. Centrum was conferred bya single dominant gene and it also carries a single dominant gene for resistance to CYR32,the two resistance genes were proved to be the same Yr gene.3. The F2:3separated population of Guinong775were used for mapping of gene to striperust race of CYR32. Eight co-dominant SSR markers(namely, Xbarc187, Xwmc694,Xwmc500, Xwmc230, Xbarc60, Xgwm18, Xgwm264and Xbarc61) showed polymorphismsbetween the parents and DNA bulks by bulked-segregant analysis, The resistance gene,located close to the centromere of chromosome1B was closely linked to Xwmc230andXbarc187with genetic distances of1.7and2.1cM, respectively.4. The results of allelism showed that the stripe rust resistance gene YrGN775wasdifferent from Yr24, Yr26, Yr15and YrCH42that on same chromosome. Through theevaluation of resistance in seedling test, molecular marker analysis and chromosomal locationand allelic determination, it had been known that YrGN775was different from the abovestripe rust resistance gene, initially identified as a new stripe rust resistance gene. |
