Genetic diversity and population structure of sorghum [Sorghum bicolor (L.) Moench] in Ethiopia as revealed by microsatellite markers

Ethiopia is the center of origin of sorghum (Sorghum bicolor L.). Understanding of the genetic diversity of the species is fundamental to design appropriate conservation and management strategies. The present study addressed the genetic diversity of sorghum accessions collected from major growing regions of Ethiopia. Eighty sorghum accessions representing five populations namely Amhara, Dire Dawa, Oromia, Southern Nations, Nationalities and Peoples (SNNP) and Tigray were analyzed with 11 simple sequence repeat (SSR) markers. Analysis of molecular variance (AMOVA) was conducted to evaluate genetic variation within and among populations. The unweighted neighbour-joining-based cluster analysis, principal components of analysis (PCoA) and structure analysis were done to elucidate clustering of populations. The polymorphic information contents (PIC) ranges from 0.50 to 0.86. A high within-populations genetic diversity was confirmed with gene diversity values ranging from 0.51 to 0.77. AMOVA revealed 93.26% of the total genetic variation within populations and 6.74% among populations. Cluster analyses did not show clear grouping of accessions according to their geographical origins, confirming gene flow (Nm = 6.65) among populations. In conclusion, the SSR markers used were polymorphic and highly informative Oromia and Amhara populations displayed genetic diversity greater than mean value of 0.67 suggesting possible target populations for breeding and conservation.