Molecular variation and genetic relationships among Aegilops tauschii accessions based on CAAT-box derived polymorphism

The importance of wild relatives in wheat breeding has caused a lot of investigations to study the genetic diversity and population structures in different species of wild wheat, using various molecular markers. The purpose of this study was to investigate the molecular diversity of 90 different accessions of Aegilops tauschiiand analyzing the genetic structure for clustering the populations using CAAT box-derived polymorphism (CBDP) markers.

In the present study, the genetic diversity and population structure of 90 different accessions of Ae. tauschii collected from different geographical areas of Iran, was evaluated using 12 CBDP primers.

Based on the results, the 12 primers amplified 141 bands in which 91 were polymorphic with an average of 7.58 bands pre primer. The polymorphism information content (PIC) and marker index (MI) for the CBDP primers ranged from 0.40 to 0.49 and 1.49 to 4.99, respectively. Primers CB9, CB12 and CB1 showed a high efficiency in genetic discrimination of evaluated accessions. Population structure analysis classified evaluated accessions into three main groups with 10, 18 and 30 accessions respectively and other accessions recognized as a mixture accessions. In this study, subpopulation NO.1 had the highest values of genetic diversity indices such as number of effective alleles (Ne), Shannon index (I) and heterozygosity (He). Among Ae. tauschii populations a very low genetic differentiation (Gst: 0.03) and high gene flow (Nm: 18.58) were observed. The dendrogram resulted from cluster analysis categorized the assessed accessions into three clusters which accordance with genetic structural analysis results.

Overall, the results of different parameters showed that the CBDP, is an appropriate marker system for assessing the genetic diversity of Aegilops tauschii accessions. Regarding to the results of genetic structural analysis and diversity parameters, a conservation program is recommended for management of Aegilops germplasm as a valuable genetic resource in the wheat breeding programs.