Résumé
Throughout their domestication process, the evolution of cultivated plants has been in part driven by their intimate relationships with humans, resulting in strong directional selection and short and long-range dispersal movements due to the farmers' practices and their social organization. Beside these anthropic effects, gene flow with wild relatives remained highly active, leading to introgression events in both compartments. African sorghum constitutes a relevant case study as it is grown close to its wild relatives and its diversity is modelled by specific anthropic drivers. To unravel the origin and evolutionary history of sorghum, an adequate sampling of the cultivated and wild compartments as well as the correct classification of each analyzed accession is a prerequisite. However, as sorghum is cultivated in sympatry with its wild relatives and as gene flow between the two compartments may occur, unambiguous assignments of accessions in these 2 compartments is far from obvious. Here, we used a combination of grain morphological and genomic data to validate the status of the accessions (wild vs cultivated) and investigate their evolutionary relationships. In addition, the guinea margaritiferum sub-race which has been suggested as a second potential domestication event in Western Africa has been more intensively sampled. We genotyped 139 wild samples and 243 cultivated accessions representative of the worldwide diversity, among which 50 guinea margaritiferum. We identified two margaritiferum groups that are genetically close to a group of wild accessions from Mali and bear signals of introgression with wild accessions from out of Western Africa but also with cultivated guinea from Western Africa. Our results indicate a complex history of the sorghum domestication, especially in Western Africa where gene flow between wild and cultivated sorghums might have led to the emergence of a peculiar group of sorghum.