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Graft and seed propagated apricots in North Africa (Algeria, Morocco and Tunisia) are identified as being from the southwestern Mediterranean gene pool. However, recently introduced varieties from northern Mediterranean areas are also encountered in this region. Do gene exchanges occur between local apricot and introduced varieties? We addressed this question by analyzing the genetic structure of 183 accessions using 24 nuclear microsatellite markers and a model-based Bayesian clustering method. We classified these accessions into 4 genetic clusters: cluster 1 from Morocco, cluster 2 from northern, central and southern Tunisia which were all propagated by grafting, cluster 3 from the oasis region in Tunisia and the Messaad region in Algeria, and finally, cluster 4 (green) included accessions belonging to the northern Mediterranean gene pool. These accessions were more diversified and genetically differentiated with respect to local North African apricot. The results revealed the presence of admixed accessions between the local gene pool and introduced varieties, mainly in seed propagated populations, thus highlighting the presence of gene exchanges between northern and southern Mediterranean countries. Our findings should be useful for improving the management and conservation of Maghrebian apricot genetic resources. (C) 2013 Elsevier B.V. All rights reserved.