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Genetic diversity of coconut trees. RFLP study of the large collection of the M. Delorme station in Côte d'Ivoire

Lebrun P., Baudouin L., Grivet L., N'Cho Y.P., Glaszmann J.C.. 1999. In : Shearago Internati. The international conference on the status of plant and animal genome research: final program and abstracts guide = [Conférence internationale sur l'état de la recherche du génome des plantes et des animaux : programme final et résumés]. New York : Scherago International, p. 188-188. Plant and Animal Genomes Conference. 7, 1999-01-17/1999-01-21, San Diego (Etats-Unis).

There is a large collection of coconut trees in Côte d'Ivoire which contains more than 60 different cultivars. The genetic diversity of this collection has been studied with molecular markers. Two hundred and eighty-nine trees representing 26 tall and 16 dwarf cultivars or sub populations have been analyzed. RFLP markers were scored as present or absent and several Factor Analyses of Correspondences (FAC) were performed. Three major genetic groups of coconut trees were identified. The first group, referred to as Indo-Atlantic, includes cultivars from West Africa and India. The second group or Pacific group, includes cultivars from East Asia, Papua New Guinea and all the islands of the Pacific. The third group, which is intermediate between the first two, encompasses cultivars from the Indian Ocean. Part of the data could be translated into genotypes. Population genetics analyses were performed on the three major groups and several subgroups were determined. Within these subgroups, no genotypic differentiation was observed. This classification is very useful for breeders in order to efficiently plan breeding programs. It is also important to help identify tolerance to diseases. In a subgroup containing three dwarf cultivars, one was known to be tolerant to the lethal yellowing disease; we verified that the other two cultivars were also tolerant. The development of new tools, like microsatellites, will accelerate diversity studies as well as cultivar identification. It will also allow the discrimination between some genetically close dwarf cultivars which were not differentiated with RFLP probes. (Texte intégral)

Mots-clés : cocos nucifera; collection botanique; variation génétique; marqueur génétique; rflp; classification; méthode statistique; polymorphisme génétique; côte d'ivoire; cocotier nain; cocotier grand

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