Genetic structure of Mediterranean apricots by SSR fingerprinting
Abstract
Apricot (Prunus armeniaca L.) is an important fruit species especially in the Mediterranean bassin area. The genetic structure of apricot cultivars in this region was studied in order to shed light on the evolutionary history of this species. A sample of 207 patrimonial accessions was collected from different Mediterranean countries: Algeria, France, Italy, Morocco, Tunisia, Turkey, and Spain. Molecular characterization was performed using 25 SSR markers, selected according to high level of polymorphism, transferability between Prunus species, and localisation over the eight linkage groups of the Prunus genome. Statistical treatment of the dataset was undertaken using a model-based Bayesian clustering analysis implemented in the STRUCTURE program. It allowed assignment of the studied accessions into four distinct genetic clusters (Fst=0.122). A gradient of decreasing genetic diversity from the east to the south-west of the Mediterranean area was also evidenced. An interesting new pattern based on the discrimination of a ‘Maghreb’ cluster was revealed for the first time. These results clearly open new research lines dealing with the establishment of a nested core collection at the Mediterranean level, and with the prospective development of genetic association studies.