Phylogenetic relationships among Iranian and Spanish date palms (Phoenix dactylifera L.) revealed by microsatellite markers

Summary

Although Iran and Spain are the leading producers of date palm (Phoenix dactylifera L.) in the World, evaluations of genetic relatedness among their major cultivars have been poorly documented. This study was undertaken to assess the phylogenetic relationships of 61 Iranian date palm genotypes grown in different geographical regions, with 14 Spanish genotypes, using 28 microsatellite (SSR) markers. Twenty-five of the 28 primer pairs amplified a total of 103 polymorphic alleles, with an average of 4.12 alleles per locus. The average values of the expected heterozygosity (H _e) and polymorphic information content (PIC) were 0.45 and 0.43, respectively. Neighbor-Joining cluster analysis, based on Nei’s genetic distances, divided the 75 date palm accessions into four major clusters, with no tendency to cluster on the basis of geographical provenance. Analysis showed the maximum level of similarity between the important Iranian population from Minab City and the Spanish genotypes. In contrast, the Bandar Abbasi population showed the maximum level of differentiation from the Spanish population. Our findings indicate that the 61 Iranian date palm genotypes were sufficiently diverse for future breeding programmes and that they had a similar genetic background to the 14 Spanish genotypes. The 25 SSR loci could also provide an informative marker system for the management and geographic partitioning of date palm varieties.