Microsatellite marker-based identification and genetic relationships of millennium olive cultivars in Tunisia

Abstract Microsatellite markers were used to characterize the millennium olive cultivars localized in nine different archeological sites in Tunisia. Thirty genotypes were considered for genetic fingerprinting using 10 pairs of microsatellite primers. The number of alleles per locus ranged from 3 to 5, with a mean of 3.7 alleles per primer pair (a total of 37 alleles). The observed heterozygosity ranged from 0.4 to 1, while the expected heterozygosity varied between 0.37 and 0.74. The polymorphism information content values ranged also from 0.37 to 0.74. The mean polymorphism information content value of 0.61 for the SSR loci provided sufficient discriminating ability to evaluate the genetic diversity among the millennium cultivars. The UPGMA cluster analyses using Jaccard's index permitted a segregation of the thirty millennium cultivars in three main groups and revealed that most of the millennium cultivars grouped according morphological parameters of the fruit and the endocarp and no clear clustering trends were observed according to their geographic origin. As a sequel to the present work, new surveys should be made in the archeological sites localized in North and the Center of Tunisia to sample more cultivars and to draw a clearer picture of the diversity of the Tunisian millennium olive germplasm.