Assessment of genetic diversity in Turkish oregano (Origanum onites L.) germplasm by AFLP analysis

Origantum onites (L.) is one of the most widely traded culinary herb species in Turkey. Despite limited knowledge on the level of genetic diversity, its use as a source of seed for planting is widespread. To initiate a selective breeding programme, Amplified Fragment Length Polymorphism (AFLP) analysis was used to estimate genetic diversity within the oregano germplasm collection of the Aegean Agricultural Research Institute of the Ministry of Agriculture and Rural Affairs, Turkey. Forty-four Origanum accessions were analysed with ten Eco RI-Mse I primer combinations. In total, 365 unambiguous, selectively amplified polymorphic fragments were detected and 294 polymorphic bands were scored for analysis. Seven main groups were identified by the Unweighted Pair Group Method with Arithmetic Mean (UPGMA) clustering using Jaccard's pairwise similarity coefficient. When this genetic analysis was compared with the sites of collection of the accessions, there was no close genetic similarity among accessions related to their growing region. Relatively low genetic similarity (0.396-0.725%) between accessions indicated that the rate of gene flow between Origanum species was high, as a result of cross-pollination. The results of this study indicate that a broad range of genetic variability exists between accessions of oregano and that future breeding programmes could be improved, based on these data, by selecting materials with maximally different AFLP fingerprints.