Analysis of genetic diversity in wheat genotypes using microsatellte markers and identification of informative markers for rust resistance related characters

Information about genetic variation level of plant germplasms and determination of breeding materials genetic relationships are the fundamental step in plant breeding programs. In the present study, genetic diversity and relationships of 70 wheat lines and varieties used in the Iran rust breeding programs were evaluated by means of 104 micro satellite loci. Among these, 71 markers showed polymorphic and score able banding patterns. In total, 592 polymorphic alleles were amplified in the studied genotypes with an average of 8.53 alleles per locus. The Xcfa2099 and Xcafl070 markers with 2 alleles and Xgwm46 with 18 alleles revealed the minimum and maximum number of allele, respectively. The average of polymorphic information content (PIC) value was 0.709±0.018 with a range of 0.166 to 0.902. The Xcfa2099 and Xgwm46 markers had the minimum and maximum PIC values, respectively. Cluster analysis on the basis ofNeighbor-joinig and UPGMA algorithms and distance coefficients based on the absence or presence of alleles and the allelic frequency at the micro satellite loci was performed to group the genotypes studied. Among the resulting dendrograms, dendrogram obtained from Neighbor-joinig algorithm based on Roger's distance was considerd as the best method for grouping of genotypes. Analysis of molecular variance (AMOV A) showed maximum groups differentiation in the dendrogram's cutting point with 4 clusters. With 4 group, between groups variation determined 57% of total genotypic molecular variance. In this grouping, the most of related lines such as sister lines Bolni 1 and Bolani2, W s-82-13 and M -82-14 as well as some lines from CIMMYT (including CIMMYT and PRWYT-DT lines) were closely grouped. A total of 185 specific alleles were determined for these 4 groups where groups 1 to 4 had 56, 37, 55 and 37 specific alleles, respectively. In principal component analysis, two first components explained 9.18 and 5.95 percentage of markers variance, respectively. Biplot presentation of genotypes using two first components revealed grouping pattern almost similar result to that of cluster analysis. Multiple stepwise regression analysis was performed to determine chromosomal regions involve in yellow rust resistance identified 8, 10 and 10 informative markers for AUDPC, rAUDPC and ACI in field evaluation and 13 and 9 for LP and IT in seedling stage in greenhouse evaluation, respectively.