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The genetic diversity organization and evaluation of relationships within Tunisian date-palm cultivars were assessed using the random amplified microsatellite polymorphism (RAMPO) and amplified fragment length polymorphism (AFLP) methods. 18 combinations of random/ISSR primers and six AFLP primers combinations were tested with DNAs isolated from 40 date-palm cultivars. Our results show that using both markers systems, the Tunisian date-palm germplasm is characterized by a large and continuous genetic diversity. In addition, due to the greater number of markers per assay, the AFLP technique seems to be more informative than the RAMPO method. In fact, 186 and 428 polymorphic bands were detected using RAMPO and AFLP primers, respectively. Moreover, AFLP markers were found most polymorphic with the highest average PIC value (0.7) and marker index (50.54). In addition, independent as well as combined analyses of the cluster analyses of the RAMPO and AFLP fragments showed that cultivars are clustered independently from the sex of trees or else their geographical origin. On the other hand, based on Pearson and Spearman correlation between RAMPO and AFLP distance, matrices were positive and highly significant. This result indicates good congruence between these two molecular markers. The opportunity of the designed methods is discussed with the molecular characterization of genotypes in order to enhance the conservation and the improvement of the local date-palm germplasm.

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Genetic variability in date palm genotypes collected from different regions of southern Tunisia was analyzed using a Start Codon Targeted (SCoT) marker system. Thirty-one accessions collected from three locations were investigated. One hundred and nine amplicons were produced among which 84 % were polymorphic. The PIC value and the Rp values testified of the efficiency of used primers. The percentage of polymorphic loci (Pp) varied from 44.57 to 83.70 %, Nei‘s gene diversity (H) from 0.175 to 0.273 with a mean of 0.228, and Shannon‘s information index (I) values ranging from 0.257 to 0.409 with an average value of 0.338 were illustrated. The Tunisian date palm populations exhibited high genetic differentiation (GST = 0.319) and gene flow (Nm = 1.063). The AMOVA analysis presented 70 % of the variation within the population and 30 % of the variation between them. Phylogenetic analysis and the Bayesian clustering approach also revealed high genetic variation among genetic variants with a net divergence of the wild insular population of Kerkennah from other cultivars. The present investigation suggests the effectiveness of the SCoT marker system to estimate the genetic diversity of Phoenix dactylifera genotypes.