Genetic diversity and population structure of Teucrium polium (Lamiaceae) in Tunisia.

Random amplified polymorphic DNA markers were used to assess the genetic diversity within and among seven Tunisian diploid and polyploid populations of Teucrium polium L. from five bioclimatic areas. Out of the 141 bands generated from eight selected primers, 124 were polymorphic. The genetic diversity within a population (Shannon's index) was high and varied according both the ploidal levels and bioclimatic zones. The genetic differentiation among populations assessed by G (ST) and Phi(ST) statistics was high, suggesting a low level of gene flow among them. The major proportion of the variation was attributable to individual differences within populations. The UPGMA analysis based on Nei and Li's coefficient showed that individuals from each population clustered together. In a dendrogram using the Phi(ST) distance matrix, population grouping is concordant with bioclimates and cytotypes. Conservation strategies should take into account the level of the genetic diversity of the populations according to their bioclimate and ploidal levels.