Identification Of Wheat Leaf Rust Resistance Genes In 42 Wheat Cultivars And QTL Mapping For Adult-Plant Resistance Genes To Leaf Rust In Wheat Variety N.Strampelli

Wheat,as one of the most important food crops,provides about a quarter of the food calories for humans.Unfortunately,wheat rust has been threatening wheat production for thousands of years,especially wheat leaf rust which occurs wordwide and leads to yield losses,even no yields in the year of this disease outbreaking.Global warming accelerates the occurrence and prevalence of wheat leaf rust.As a result of long-term and large-area cultivating wheat varieties with limited resistant genes,selection pressure on the pathogenic bacteria is produced,causing decrease of resistant varieties against pathogens.Therefore,exploring new resistant genes and broadening the genetic resources of disease resistance are important to ensure the sustainable development of wheat production.The present study aims to identify resistant genes related to wheat leaf rust and analyse wheat leaf rust resistance of adult plants by QTL.1.To seedlings of 36 wheat varieties containing known resistance leaf rust gene vector and wheat varieties,1 8 physiological races of leaf rust with different virulence were inoculated.Subsequently,the possible resistance leaf rust genes in the tested varieties were derived according to the response type of wheat varieties to different physiological races of leaf rust.Collecting molecular markers that closely linked with known resistance leaf rust genes,the results of gene derivation were thereby verified.The slow rust varieties were screened out by ANOVA.Analysis of leaf rust resistance by combining gene derivation with molecular marker detection showed that 7 genes against leaf rust were derived from 42 foreign wheat varieties,including(Lr1,Lr10,Lr14a,Lr26,Lr2a,Lr17 and Lr20).Hybride du Jubile and other 15 wheat varieties contain Lr1,Craftsman and other 2 varieties contain Lr14a,Rimpaus and other 4 varieties contain Lr17,Parad and other 4 varieties contain Lr2a,Parade and Craftsman contain Lr10,Scipion and Milpain contain Lr37,Rooster and other 28 varieties contain Lr46,Rieti contains Lr20,Civic contains Lr26,Carahue contains Lr34,respectively.Additionally,fifteen varieties were screened for slow rust.2.N.Strampelli,introduced from Italy,has good resistance to stripe rust in the field.In order to further analyze the adult leaf rust resistance genes contained in the cultivar and locate the QTL for leaf rust resistance,193 RIL populations of N.strampelli/huixianhong were monitored in two places from 2018 to 2020,and planted in Baoding,Hebei Province and Zhoukou,Henan Province,respectively.According to the severity of phenotypic identification and genotypes screened by SNP and SSR molecular markers,QTL software was used to analyze the resistance sites,and then combined with the results of leaf rust resistance gene mapping to find the disease resistance sites with both stripe rust and leaf rust resistance.A total of 3 QTL sites for leaf rust resistance were detected in four environments,located on chromosome 2A and 5B respectively.Two QTL sites were located on 2A,tentatively named as QLr.hbau-2A.1 and QLr.Isb-2A.2.QLr.hbau-2A.1 was detected in Baoding in 2018&2019 and Henan in 2019,accounting for 14.4%,12.2%and 17.0%of variation rates respectively.QLr.hbau-2A.2 was detected in Baoding in 2018&2020,accounting for 13.2%and 12.5%of variation rates respectively.One QTL site was located on 5BL chromosome and tentatively named as QLr.hbau-5B.It was derived from the resistant parent N.Strampelli.QLr.hbau-5B was detected in all four environments,and was closely linked to the stripe rust resistance gene Yarn.S,which explained 18.6%,19.1%,17.8.%and 18.1%of the variation rates respectively.