Exploring antioxidant potential and microsatellite based genetic diversity in different germplasm of Aegilops tauschii

Exploration of genetic diversity in wild relative is ideal strategy for improving wheat cultivars to drought stress conditions in breeding program. Aegilops tauschii (goat grass) is a diploid (2n = 2x = 14, DD) wild species, thought as the D genome contributor to bread wheat. In this study the genetic diversity of 32 Ae. tauschii accessions collected from different provinces of Pakistan were assessed using 28 simple sequence repeat (SSR) markers. In addition to genetic analysis, we also investigated their antioxidants enzymes (Superoxide dismutase, SOD; Peroxidase, POD) responses for osmotic stress tolerance, induced by polyethylene glycol in completely randomized design (CRD). The variations in antioxidant enzymes activities among accessions ranged in between 4.97 (POD) and 112.02% (SOD), under osmotic stress conditions. High variability and positive correlations of SOD and POD with osmotic stress tolerance, indicated diversity among Ae. tauschii accessions and could be used as selection criteria. Additionally, molecular characterization through SSR markers revealed high genetic variation among accessions and supported the SOD and POD based diversity. A total of 137 alleles were observed with the mean values of 4.89 alleles per locus. The polymorphism information content (PIC) ranged from 0.21 (Barc142) to 0.85 (Barc124) with an average value of 0.59. The genetic distance coefficient range was between 0.25 and 0.93. All accession were clustered by the unweighted pair group method with arithmetic mean UPGMA. The accessions did not align with their geographical regions, thereby suggesting that there is not any relationship between molecular diversity and eco-geographic diversity.