Genetic Variability and Population Structure of Ethiopian Yams (Dioscorea spp.) Based on SSR Markers

In order to implement breeding and conservation measures, it is crucial to evaluate the extent of genetic diversity. Hence, this study aimed to evaluate the genetic diversity and population structure of 31 yam accessions collected from various agro-ecologies in Ethiopia based on 10 SSR markers. Our results showed the existence of a wide range of genetic diversity among the yam accessions. A total of 72 alleles were amplified and the number of alleles per marker ranged from 5 to 11, with an average of 7.2. The average values of expected and observed heterozygosity were 0.38 and 0.30, respectively. The average polymorphic information content per marker was found to be 0.30, indicating the markers are reasonably informative towards detecting the genetic diversity among accessions. The level of population polymorphism was found to vary from 68.06% (Sheka) to 97.22% (Bench-Maji and Gambella), with an average of 85.2% among populations. Accessions from Bench-Maji and Gambella resulted in higher values for all diversity indices; hence, this area can thus be considered a potential site for in situ conservation. Analysis of molecular variance showed that the within-population variations contributed more to the observed genetic diversity. Similar results were also evident in the multivariate analyses, in which accessions were grouped without a distinct pattern of geographic origins. The high within-population variation indicated the potentiation of on-farm diversity for establishing a breeding and conservation program.