Analysis of genetic Diversity and relationships among different genotypes of Triticum aestivum and Aegilops tauschii using SSR markers

Triticum and Aegilops genera are the main gene pool of bread wheat due to their breeding potential such as tolerance to various abiotic and biotic stresses. The main objective of this study was to evaluate the genetic diversity in 95 landraces and wild relative accessions belonging to T. aestivum and Ae. tauschii using microsatellite (SSR) markers. A total of 49 polymorphic fragments were amplified using 25 tested primers. The average values of number of alleles, polymorphic information content (PIC) and gene diversity (H) were 1.96, 0.32 and 0.41, respectively. The results of molecular variance analysis (AMOVA) showed the highest portion of genetic variance referred to within species compared to between them. According to genetic variation parameters, the highest values of variation parameters were estimated for Ae. tauschii than T. aestivum accessions. Cluster analysis based on Jaccard’s coefficients and neighbor-joining algorithm grouped all investigated accessions into two main clusters, so that some of accessions from each species were placed in the same sub-cluster. The result of principal coordinate analysis (PCoA) revealed that the first two components accounted for 50.38% of the total molecular variation. The biplot rendered based on the first two components was accordance with the grouping pattern obtained from cluster analysis. The population structure analysis grouped all investigated individuals into four main subpopulations so that the average of FST index among them was 0.50. In general, our results revealed a high level of genetic diversity within T. aestivum and Ae. tauschii species as well as the used markers were capable well to present of this diversity.