| Wheat leaf and stripe rusts are the most serious and widespread diseases in China.Since the founding of China in the last century,many outbreaks of diseases have erupted in the main wheat production areas,which directly led to the loss of wheat quality and yield to varying degrees.At present,breeding and utilizing durable resistant cultivars are economic,safe,and effective measures to control these rust diseases.This study is divided into two parts:(1)analysis of leaf rust resistance genes in 71 wheat cultivars;(2)the quantitative trait locus mapping for adult plant resistance genes to stripe rust in Weimai 8.1.In this experiment,a total of 71 wheat cultivars from the middle-lower reaches of the Yangtze River,a set of 35 differential lines with known leaf rust resistance genes and susceptible cultivar Zhengzhou 5389,were tested for response to 20 P.triticina pathotypes with different virulence to finish gene postulation work at the seedling stage in the greenhouse.According to the results of seedling infection type,these varieties could be deduced whether they contained known leaf rust resistant genes.At the same time,twelve specific molecular markers(STS or SCAR),were used to verify the results of gene postulation.The origin of known leaf rust resistance genes carried in wheat cultivars were further explained by pedigree analysis.Through marker detection,gene postulation and pedigree analysis,we found that 28 of the 71 tested cultivars may carry 7 known resistance genes to leaf rust,Lr1,Lr10,Lr14 a,Lr17,Lr26,Lr34 and Lr46.These genes existed in the form of single gene or multiple genes in these cultivars.Lr1 was existed in eight cultivars,and eight cultivars contained Lr26.Lr34 and Lr46 were detected by their gene-specific molecular markers.Seven cultivars were found to contain Lr34,and thirteen cultivars contained Lr46.Lr10 was existed in a variety,Zhenyuan SC16 might carry leaf rust resistance genes Lr14 a and Lr17.Wheat cultivars with leaf rust resistance genes identified in this experiment can be further used in disease resistance breeding.2.The wheat variety Weimai 8 showed high resistance to stripe rust at adult stage.It is expected that Weimai 8 might contain adult plant resistance genes.Therefore,the QTLs of adult plant resistant to stripe rust were mapped in this study.A total of 163 recombined inbred lines(RILs)derived from Weimai 8/Zhengzhou 5389 were planted in the experimental fields of Baoding,Hebei province during the 2015-2016,and Mianyang,Sichuan province during the 2016-2017 and 2018-2019 cropping reasons,respectively.The disease severity data was obtained as phenotypic data after inoculating and recording in the field.The markers(SSR and SNP)were used to screen markers among parents,then the polymorphic markers were used for further detection to the entire RIL population for QTL analysis to obtain genotype data.Field phenotypic data and genotype data were used in QTL analysis for resistance to stripe rust by QTL Ici Mapping 4.0 and Map Manager QTXb20.In this study,four QTLs were identified located on 1B,2A,2B and 7D chromosomes,and these QTLs were detected in all environments.The results showed that QTLs on the 1B and 2A chromosomes were provided by the known resistance genes Yr9 and Yr17 with a phenotypic variance expression from 11.56%-16.64% and 9.35%-12.70%,respectively.One QTL resistance for leaf rust was found on chromosome 2BS with a phenotypic variance expression from 7.27%-9.95%.There are many known genes and QTLs on 2B chromosome,and the relationship between this locus and these loci still needs to be verified by further studies,so it is not sure whether QYr.wm-2BS is a new QTL.Therefore,the relationship between this locus and these loci needs further study and verification.The QTL on 7DS chromosome with a phenotypic variance expression from 11.49%-15.07% might be a new QTL.The QTLs for adult rust resistance in this experiment can provide basic theory for further studies. |
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