Résumé
Most of the cultivars of mandarin type cultivated in tropical areas were bred in mediterranean climatic zones. Some characters of these mandarin varieties are not adapted or are not expressed in hot and wet tropical zones, such as West Indies. The aim of our work is to create and offer to producers from these areas some varieties fitting the ecological and environmental constraints as well as the local market demand. Previous studies of citrus varietal screening in Martinique gave us a list of potential parents that could transmit the expected characters (productivity, fruit size, taste, low rind adhesion, pests and diseases resistance). To achieve the seedless character of these new varieties, we produced triploid plants according to the creation scheme of citrus varieties developed by Cirad in Corsica. We crossed a monoembryonic and self-incompatible female parent (Fortune mandarin) with four male parents (Murcott tangor, Hansen mandarin, Minneola and Orlando tangelo). This crossing phase was conducted in Corsica, in the Inra/Cirad citrus germplasm collection. After visual screening, 343 small seeds were sent to Martinique, where in vitro embryo rescue was realized. Triploids were screened by flow cytometry and grafted onto Citrange Carrizo rootstock. At the present time, 220 triploid hybrids are in the field, at Rivière-Lézarde station in Martinique, and will be evaluated and selected with a specific multicriteria grid. First results are expected within 4 to 8 years. (Résumé d'auteur)