Evaluation of genetic diversity of Ethiopian mango genotypes and comparison with a worldwide germplasm collection

Mango is a fruit crop holding significant economic importance in east Africa. However, the genetic diversity of Ethiopian mango remains so far unexplored. Therefore, we carried out the genetic characterization of Ethiopian populations and germplasm resources using eight SSR markers. A total of 162 domestic mango accessions were compared with the available information on the genetic profile of 73 international reference cultivars maintained in the European mango reference collection. We detected 69 alleles and found a high level of heterozygosity (0.68) among Ethiopian mango populations. As expected, there was broader genetic variability in the international reference germplasm (i.e., higher expected heterozygosity, allelic richness and number of private alleles). The study revealed frequent cases of mismatches among the commercially distributed varieties in Ethiopia and their synonymous cultivars in the international reference germplasm. The UPGMA dendrogram and model based structure analysis showed the relationship of locally grown mango trees with commercially available cultivars in Ethiopia. The clustering and differentiation estimates indicate a consistent relationship among accessions, aligning with their geographical distribution. Structure analysis identified three subgroups within the entire dataset of genotypes and highlighted the distinctness of the domestic gene pool in comparison to the accessions in the international collection. Furthermore, our analysis identified unique cultivars within the reference germplasm that exhibited close genetic proximity to the domestic samples, thereby providing evidence of their significant role in diversifying Ethiopian mango populations. These findings contribute to the effective management and utilization of mango germplasm in Ethiopia and will enhance current breeding efforts in the country.