Genetic diversity and population structure of Vernonia [Vernonia galamensis (Cass.) Less] populations from Ethiopia revealed by SSR markers

Abstract

Background: Vernonia (Vernonia galamensis) is a potential novel industrial crop due to high demand for its natural epoxidized oil, which can be used for the manufacturing of oleochemicals such as paints, plastic formulations (polyvinyl chloride), and pharmaceutical products. Assessment of the extent of genetic diversity in V. galamensis was the first and the most step in cultivation, breeding and genetic resource conservation. Hence, this study was aimed to assess the genetic diversity and population structure of this plant from different agro-ecologies in Ethiopia using SSR markers. Results: Twenty SSR markers were used for genetic diversity analyses of 150 individual V. galamensis accessions representing 10 populations, from which a total of 79 bands were identified for the 20 loci. All the loci used showed high polymorphism that ranged from 0.50 to 0.96, while the mean observed heterozygosity (Ho) was 0.15 across all the 20 markers evaluated. The molecular variance analysis (AMOVA) showed significant variations among populations which accounted for 11% of the variations. Populations clustering showed that the dendrogram and principal coordinate’s analysis roughly classified the accessions into four groups. However, the Bayesian model-based clustering (STRUCTURE) grouped into 6 (K = 6) major gene pools. Since, the cluster and the STRUCTURE analyses did not group the populations into sharply distinct clusters, due to presence of gene flow and mode of reproduction of the plant. Conclusions: The SSR molecular markers used in this study are highly polymorphic. Among the ten populations, East Showa and East Hararghe revealed higher genetic diversity, signaled that these areas are the hotspots for in-situ conservation of V. galamensis. In addition, the values of SSR markers such as heterozygosity, Shannon‘s index, polymorphic information content, and population clusters are important baseline information for future V. galamensis cultivation, breeding and genetic resource conservation endeavors in Ethiopia.