Exploration Of Resistance Loci Of Stripe Rust In Chinese Northern Wheat Landraces

The Chinese northern wheat landraces are the important germplasm resources.It has abundant genetic diversity and resistance genes.The wheat stripe rust or yellow rust is caused by the Puccinia striiformis West.f.sp.tritici Eriks.& Henn.,which would cause a negative effect on wheat yield.To identify new sources of resistance,the paper performed a genome-wide association study(GWAS)using a collection of 93 accessions of northern wheat landraces in northern China.There were 7107 DArT-seq and 140 SSR markers suitable for GWAS.In combination with phenotypic identification,stable and resistant germplasm resources can be selected and directly used for resistance breeding.The result is as follow:1.The resistance for wheat stripe rust of 93 accessions were evaluated under field conditions in four environments.17 of them were stable resistant to wheat stripe rust.Furthermore,combined with the result of the seedling phenotypic,3 of the 17 accessions were resistant to wheat stripe rust in all-stage.2.The molecular date of the Chinese northern wheat landraces was evaluated by 160 SSR makers.Among them,140 SSR makers were pleomorphic.There are wide variations in genetic diversity: the PIC and gene diversity for SSR markers were respectively 0.2136 and 0.2518.3.A total of 7107 DArT-seq makers were used for GWAS.The PIC and gene diversity for DArT-seq markers were respectively 0.2607 and 0.3209.Structure for DArT-seq also separated all the Chinese northern wheat landraces into two subgroups(GP1 and GP2).4.A total of 9 significant SSR makers were detected for the wheat stripe rust in Chinese northern wheat landraces using the mixed linear model(MLM)by TASSEL.Among them,one maker was associated with the resistance of stripe rust in wheat seedling stage,and the others were associated with the resistance of stripe rust in adult-stage.Combining the consensus map of wheat stripe rust resistance gene,the maker Xgwm312-2A,Xgwm174-5D,Xgwm499-5B,Xcfd223-3D,Xgwm169-6A,Xbarc172-7D and Xbarc126-7D were unreported stripe rust resistance association marker.Furthermore,the maker Xcfd223-3D,Xgwm169-6A and Xbarc172-7D were associated with multiple-effect loci which was related with disease severity(DS),disease index(DI)and area under the course curve(AUDPC)at the same time.Moreover,the SSR markers associating with the resistance of stripe rust were analyzed with the method of null allele proposed by Breseghello and Sorrels,and the maker Xcfd223-A3 was significantly associated with an excellent locus controlling IT,DS and DI.5.A total of 16 significant loci based on DArT-seq were detected for the wheat stripe rust in Chinese northern wheat landraces using MLM by TASSEL.Among them,4 makers were associated with the resistance of stripe rust in wheat seedling stage,and the others were associated with the resistance of stripe rust in adult-stage.Combining the consensus map of wheat stripe rust resistance gene,the locus QAUDPC.sicau-7B was unreported stripe rust resistance association locus.6.Under the induced environment with Pst races,7 SSR makers were significant associated with yield taits by GWAS.Two of these markers were significant associated with spikelet number(SN);three of these markers were significant associated with kernels number of spikelets(KNS);one of these markers was significant associated with spike length(SL);one of these markers was significant associated with grain weight per spike(GWS).Xpsp3000-1B,Xgwm273-1B,Xbarc133-3B and Xgwm344-7B were mapped on the position similar to the Pst resistance QTL.Moreover,a total of 24 DArT-seq makers were significant associated with yield taits by GWAS under the induced environment with Pst races.Among them,seven markers were significant associated with SN;eleven markers were significant associated with KNS,five of these markers were significant associated with SL,one marker was significant associated with GWS.Moreover,QKNS.sicau-7D,QKNS.sicau-2B.2,QSN.sicau-4B,QSN.sicau-6A and QSL.sicau-7B had genetic implications with stripe rust resistance.