Population Evolution And Genome-Wide Association Study Of Yield Traits For Wild Emmer Wheat

Wild emmer(Triticum dicoccoides L,2n=4x=28,AABB)is the donor species of common wheat(Triticum aestivum L.,2n=6x=42,AABBDD),which is considered to be an important potential gene resource for improving common wheat.In this study,the intraspecific genetic differentiation of wild emmer and their evolutionary rates of wheat A and B genomes were analyzed based on the wheat 55 K array.Two SNP loci have been detected and played important role in the domestication of wild emmer through selection signal detection.Moreover,the gene resources for Grain length(GL),Grain width(GW),100-grain weight(HGW),spike length(SL),fertile spikelet number(SN)and Plant hight(PH)were identified and analyzed based on the SNPs of A and B genome from the Wheat 55 K SNP Array by genome-wide association analysis(GWAS).The main results were followed for this study:(1)Phylogenetic trees were constructed based on the nuclear genomes of 121 wild emmer,Cultivate emmer wheat and common wheat.It was found that there was obvious differentiation between wild emmer,and cultivate emmer wheat had lower differentiation degree and close genetic relationship with hard wheat.(2)PCA and population analysis of And B genomes of wild emmer and phylogenetic trees showed that both A and B genomes of wild emmer had significant differentiation,and the Grouping of A genomes was clear and stable at all levels,while the classification of B genomes was mixed,which suggested that B genomes of common wheat might has multiple donors.(3)The selection signals showed that two significantly selected loci AX-108884190 and AX-109867478 were selected,which were close to Traes CS6A01G327700 and Traes CS2A01G136700 genes respectively,DNAJ protein genes,It may be beneficial to the adaptability of wheat to the environment in the process of transmission.(4)Six agronomic traits of emmer wheat were investigated,including PH,SL,SN,GL,GW and HGW were analyzed.The results showed that there were wide variations in the six yield traits in different environments and the correlation analysis among the six traits showed that GL significantly positively correlated with GW,HGW was significant negative correlation with SN and SL.PH significantly positively correlated with spike traits and GW.(5)A total of 10424 SNPs of A and B genomes from the Wheat 55 K Array were identified,110 stable loci significantly related to agronomic traits of emmer wheat were identified.There are 7 significant markers controlling GL,which are distributed on chromosomes 1A,2A,3A,5A,7A and 7B.There are 67 significant loci controlling GW,which are distributed on all chromosomes except 4B and 5B,15 loci controlling HGW.There are nine significant markers controlling ear length,which are distributed on chromosomes 2A,5A,6A,2B,4B and 6B.Among them,11 stable loci controlling grain characters have been verified in common wheat population,including 9 loci controlling GW and one locus controlling HGWand GL.Candidate genes were predicted for verified loci of grain traits,PH and ear traits.According to functional annotation,these loci may be related to ubiquitin ligase,cytochrome and plant hormones.