Quantitative Trait Loci Mapping Of Adult Plant Resistance To Stripe Rust In Wheat Cultivar Humai15

Stripe rust, caused by Puccinia striiformis f. sp. tritici (Pst), is one of the most importantleaf diseases on wheat in the world. Four high prevalence have outbreak in China resulted ingreat yield losses. In recent years, major yield losses were prevented by widespread andtimely applications of fungicides based on accurate monitoring and prediction of diseaseepidemics and the areas affected annually by stripe rust were on average about1.3millionhectares. The use of chemicals not only pollute the environment will also select resistantstrains, while growing resistant cultivars is considered the most effective, low-cost, andenvironmentally safe approach to control stripe rust. Unfortunately, the common used striperust resistance gene is the race specific gene which is conferred by single gene and will loseits resistance after three to five years. In order to cultivate the durable resistant varieties, thebreeders should pay more attention on the quantitative trait locus (QTL) which conferred bymulti-genes and show non-race specific adult plant resistance.On the one hand, for the sake of identification excellent new quantitative trait locus, thisstudy aimed to map QTL of adult plant resistance to stripe rust in the common wheat cultivarHumai15which show outstanding resistance in the field and obtain the tightly linked markerswhich can be used in the marker assistant selection. On the other hand, in order to test thechloroplast contamination of the BAC library, a set of PCR primers was designed for threeselected chloroplast genes. In this study, four results were got:1. Construction a mapping population of the F2:3family with174plants which derivedfrom the cross of Mingxian169and Humai15. The genetic linkage map was constructed withSSR and RGAP molecular markers.2. The F3lines were evaluated at Yangling (Shaanxi province) and at Tianshui (Gansuprovince) during the2012-2013cropping season. The infection type and disease severity (DS)were recorded and the relative area under the disease progress curve (rAUDPC) wascalculated for the QTL analysis.3. Two QTL conferring stable resistance were detected on2B and3BS chromosome by QTL IciMapping3.3. The detected QTL on2B was designated as QYr.nafu-2B and flanked bymolecular marker Xwmc477and Xbarc160which can explain13.2-26.9%of the phenotypicvariance. The detected QTL on3BS was designated as QYr.nafu-3BS and flanked bymolecular marker Xgwm389and Xbarc75which can explain8.4-9.4%of the phenotypicvariance. These two QTLs can explain21.6-37.3%of the phenotypic variance and haveadditive effect to stripe rust resistance which indicate these QTLs can significantly reducedisease severity of stripe rust on wheat cultivar Humai15.4. After846randomly selected clones were estimated by three pairs of primers designedfor three chloroplast genes. only6were positive for the tested genes, indicating that only0.71%of the clones were contaminated by chloroplast genes...