Highly polymorphic nSSR markers: A useful tool to assess origin of North African cultivars and to provide additional proofs of secondary grapevine domestication events

Twenty highly polymorphic nuclear microsatellite markers were used to assess genetic relationships among 181 grapevine accessions traditionally grown in different geographical region of the species’ range and 21 wild Tunisian samples. A total of 330 alleles were detected and extensive genetic polymorphisms were recorded either in the cultivated or in the wild compartment. A genetic structure according to accessions taxonomic status and cultivars geographical origin was revealed by multivariate analysis and Fst values. However, a considerable overlap was observed in the majority of distinguished groups. The highest level of differentiation between wild and cultivated accessions is recorded between Tunisian wild accessions and North African cultivars which are confirmed by multivariate analysis. Thus the occurrence of local domestication event of grapevines in the North African region is unlikely. North African cultivars do not derive directly from local wild populations but could mostly correspond to imported materials introduced probably from East region or derived from crosses between them. A genetic affinity between wild gene pool and cultivars of West Europe was brought to light by multivariate and Fst analysis. Pattern structure of genetic diversity in the analyzed material presents an additional proof of the occurrence of secondary grapevine domestication events in West Europe region which contributed to the evolution of the species, a hypothesis supported by recent archeobiological and molecular studies.

► High levels of genetic diversity either in wild or cultivated grapevine gene pools are revealed.
► The occurrence of local domestication event of grapevines in the North African region is unlikely.
► North African cultivars could mostly correspond to imported materials introduced probably from East region or derived from crosses between them.
► Pattern of genetic structure of the analyzed samples presents an additional proof of the occurrence of secondary grapevine domestication events in West Europe region.