Comparison between classical and Bayesian methods to investigate the history of olive cultivars using SSR-polymorphisms

Olive cultivar origins are unknown. We attempted to use multivariate analyses and based Bayesian methods to look for sites of olive cultivar geographic origins. In this study, to establish the method, forty cultivars were chosen with different chlorotypes that represent the olive RAPD-based diversity in the Mediterranean basin. We constructed a dendrogram, as reference, using molecular SSR data. Cultivar origins in the oleaster were examined by using Bayesian clustering methods. It was calculated whether some cultivars may be grouped by admixture analysis to these GRPs and how much olive cultivars admixed to the previously defined oleaster GRPs: two in the east and four in the west of the Mediterranean basin. The comparison between dendrogram and Bayesian analyses showed that when the dendrogram suggests relationships, the Bayesian method quantifies them by probabilities and proportions. The method used is applicable to microsatellite data from other crop/wild complexes.