Résumé
Development and improvement of root crops, such as yam, that are mostly vegetatively propagated, strongly rely on the possibility to exchange genetic resources. In order to allow the international exchange of healthy germplasm, CIRAD set up a yam quarantine unit in Montpellier (France) in 2002. The main goal of this quarantine unit is to ensure exchange of disease-free germplasm. For that purpose, relevant diagnostic tools, essentially aiming at the detection of virus diseases, were implemented. In order to clean up the germplasm, in vitro cultures (nodal microcuttings and meristem tip culture) were used in association with heat treatment. Distribution of germplasm was ensured with in vitro plantlets. A first transfer of yams from Vanuatu and Benin with Guadeloupe was achieved to supply the breeding program of CIRAD with parental clones. Since 2004, about 50 clones (mainly D. a/ata) have been transferred after testing for 5 virus species or genuses [badnaviruses, Cucumber mosaic cucumovirus (CMV), potexviruses, Yam mild mosaic potyvirus (YMMV), Yam mosaic potyvirus (YMV)] following the rules of international germplasm transfer (FAO-IBPGR) and the Convention on Biological Diversity. A second transfer of D. a/ata from Vanuatu to Benin is in progress. (Résumé d'auteur)