Résumé
An official certification scheme for citrus fruits controlled by the "Centre Technique Interprofessionnel des Fruits et Légumes" (CTIFL) has been taking place in France since January 1st, 1997. This certification program allows to provide budwood materials and nursery stock true-to-type and free from the most important pathogens. Agreements between CTIFL and nurserymen permit them to produce the citrus plant according to the legal specifications. The certified material is issued from registered stock which have been producing at the Research Station of San Giuliano since the 60's. At the beginning, the foundation block was composed of trees issued from nucellar selection and indexed by grafting on indicators. Now, the regeneration of citrus varieties is based on shoot-tip grafting method and allows to recover virus-free monoembryonnic varieties. Indexing is realized by biological, serological and molecular techniques and the control of the elimination of the graft-transmissib le pathogens can be achieved with tools which are more reliable and sensitive. Three or four copies of all the registered trees obtained from this program are maintained in an outdoor foundation block because of the unique sanitary status of Corsica. A protected foundation block has been created to group the initial mother trees. Pomological traits are then observed in the blocks to check the trueness-to-type. Presently, the citrus germplasm bank includes more than a thousand accessions separating in 716 citrus varieties, 253 rootstocks and 63 botanicals grouping respectively 34, 23 and 28 different species or hybrids. So far, the most economically important varieties have been integrated in the certification scheme but to greatly improve the procedure, it will also have to include the ornementals in the certification. (Résumé d'auteur)