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 to its natural epoxidised oil, which can be used for the manufacturing of polyvinyl chloride, adhesives, and petrochemicals, cosmetic and pharmaceutical products. This study is initiated for the systematic and intensive assessment of V. galamensis accessions genetic diversity through SSR molecular markers to minimize the existing research gaps, and provide a clue for germplasm conservation and further research. Results A total of 150 V. galamensis accessions were analyzed using 20 SSR markers. The markers detected a total of 79 with an average of 3.9 alleles per locus. The mean number of effective alleles was 3.06 and, the mean observed heterozygosity (Ho) was 0.15 across all the 20 markers evaluated. The marker also showed the highest percent of polymorphism that ranged from 0.50 to 0.96 with an average of 0.76. The analysis of molecular variance showed only 11% variation was among populations, 22% among individuals within populations and 67% within individuals. The largest number of migrants per generation was occurred between Derashie and Wollo (Nm=7.37) whereas the lowest values was between East Harerghe and West Harerghe (Nm =1.42). A factor analysis including dendrogram clusters and principal coordinates classified the 150 accessions into 4 groups. However, the Bayesian model based clustering (STRUCTURE) grouped into 3 (K = 3) major gene pools. These analyses showed accessions collected from the same region of origin did not often grouped entirely together within a given major groups. Conclusions Molecular genetic diversity analysis, using SSR markers was the first report in V. galamensis. All the markers used were polymorphic in the population studied. The markers detected the larger number of alleles, higher expected heterozygosity than observed heterozygosity. The markers applied to ten populations, in which East Showa and West Harerghe revealed higher genetic diversity, and can be considered as 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 an important baseline information for future V. galamensis cultivation, breeding and genetic resource conservation endeavors in Ethiopia.