Applicability of CAAT Box-derived Polymorphism Markers in Survey of Genetic Diversity in Aegilops tauschii

In this study, the molecular diversity among 95 accessions of Aegilops tauschii was investigated using a CAAT-box derived polymorphism (CBDP) marker system. Fifteen CBDP primers produced a total of 73 bands (4.87 bands per primer), of which 66 bands (91.9%) were polymorphic. The mean of polymorphic information content (PIC=0.26) and resolving power (Rp=5.62) indicated the capability of this marker system in evaluating genetic diversity in Ae. tauschii. In addition, the mean percentage of polymorphic loci, the number of observed alleles, effective alleles, the Shannon information index, and genetic diversity criterion were estimated to be 91.90%, 1.83, 1.47, 0.44, and 0.27, respectively. Analysis of molecular variance revealed that intra-population variation accounted for 96% of the total variance, while the remaining 4% was related to inter-population variation. Cluster analysis grouped the accessions into 7 main clusters. Also, according to principal coordinate analysis (PCoA), accessions were classified into six main groups, where the first two principal coordinates explained 24.19% of the total variation. The results of cluster analysis were relatively consistent with the results of PCoA. In this study, although the CBDP marker system did not completely separate Iranian accessions from other accessions however, accessions from Turkmenistan, Russia, Georgia, Turkey, Japan, and Kosovo were grouped in separate clades. Overall, the results showed that the CBDP marker system effectively identifies polymorphisms in the studied accessions. The results of this research suggest that the studied CBDP markers can be used in genetic fingerprinting and analysis of relationships between wheat and its related germplasm to evaluate various agronomic traits as well as tolerance to environmental stresses.