The genetic profiling of relict grapevines from the Atlas region reveals different ancestral inputs shaping Moroccan germplasm

Abstract

Morocco, located at the crossroads of ancient Mediterranean viticultural routes and within the natural distribution range of wild grapevine, can represent a valuable yet underexplored reservoir of grapevine diversity that might be useful as a source of adaptive traits to improve grapevine resilience to current climatic scenarios. In this study, we conducted a systematic prospection of former viticultural areas in the Beni Mellal–Khénifra region of the Atlas region in central Morocco that led to the identification of 67 relict grapevines. These plants were genetically characterized using a combined strategy based on 13 nuclear SSR markers and 240 SNPs, an approach that revealed 20 distinct genetic profiles. Seven of them corresponded to known cultivated varieties, while the remaining profiles were not found in international reference databases. Several unidentified genotypes were detected repeatedly across distant locations, suggesting former local relevance for grape production. Parentage analyses uncovered previously unreported familial relationships among Moroccan varieties, and identified potential ancient key founder genotypes contributing to regional grapevine diversity. Comparative analyses with a representative panel of Western Mediterranean wild and cultivated grapevines demonstrated that most relict plants belong to the Vitis vinifera ssp. sativa gene pool. However, a subset of them displayed significant genetic contributions from V. vinifera ssp. sylvestris, indicating historical hybridization events between both subspecies. Overall, our results indicate that the traditional grapevine assortment of the Moroccan Atlas region was shaped by three main sources of genetic diversity: autochthonous Maghrebi varieties, introduced varieties from the Iberian Peninsula, and local sativa-sylvestris hybrids locally adopted for grape cultivation. This complex genetic background reflects a long history of grapevine cultivation, exchange, and adaptation in Morocco. The identification of uncatalogued grapevine genotypes and multiple partial parentage relationships highlights the high level of genetic erosion suffered by Moroccan viticulture, but also emphasizes the considerable potential of relict grapevines as a source of unique genetic resources. These findings support the urgent need for conservation, further agronomic evaluation, and potential valorisation of Moroccan grapevine germplasm in the context of climate change adaptation.