Investigation of genetic diversity of Iranian wild relatives of bread wheat using ISSR and SSR markers.

Background: Wild relatives of wheat are one of the most important genetic resources to use in wheat breeding programs. Therefore, identifying wild relatives of wheat and being aware of their diversity, is undeniably effective in expanding the richness of the gene pool and the genetic base of new cultivars and can be a useful tool for breeders in the future. The present study was performed to evaluate the molecular diversity among 49 accessions of the genera Aegilops and Triticum in the National Plant Gene Bank of Iran using two DNA-based markers, i.e., SSR and ISSR. Also, the present study aimed to examine the relationships among the accessions studied belonging to different genetic backgrounds.

Results: Ten SSR and tan ISSR primers produced 2065 and 1524 polymorphism bands, respectively. The number of Polymorphic Bands (NPB), the Polymorphism Information Content (PIC), Marker Index (MI), and Resolving Power (Rp) in SSR marker was 162 to 317, 0.830 to 0.919, 1.326 to 3.167, and 3.169 to 5.692, respectively, and in the ISSR marker, it was from 103 to 185, 0.377 to 0.441, 0.660 to 1.151, and 3.169 to 5.693, respectively. This indicates the efficiency of both markers in detecting polymorphism among the accessions studied. The ISSR marker had a higher polymorphism rate, MI, and Rp than the SSR marker. Molecular analysis of variance for both DNA-based markers showed that the genetic variation within the species was more than the genetic diversity between them. The high level of genomic diversity discovered in the Aegilops and Triticum species proved to provide an ideal gene pool for discovering genes useful for wheat breeding. The accessions were classified into eight groups based on SSR and ISSR markers using the UPGMA method of cluster analysis. According to the cluster analysis results, despite similarities between the accessions of a given province, in most cases, the geographical pattern was not in accordance with that observed using the molecular clustering. Based on the coordinate analysis, neighboring groups showed the maximum similarities, and distant ones revealed the maximum genetic distance from each other. The genetic structure analysis successfully separated accessions for their ploidy levels.

Conclusions: Both markers provided a comprehensive model of genetic diversity between Iranian accessions of Aegilops and Triticum genera. Primers used in the present study were effective, informative, and genome-specific which could be used in genome explanatory experiments.