Assessing genetic diversity in a germplasm collection of kola trees (Cola nitida (Vent.) Schott and Endl.) using enzymatic markers

摘要

The genetic diversity of a germplasm collection of kola trees (Cola nitida (Vent.) Schott and Endl.) maintained in Cote d'Ivoire and consisting of accessions originating from Cote d'Ivoire, Guinea and Nigeria, was assessed using 6 enzyme systems and 11 loci. These enzyme systems were GPI with 3 loci and 17 alleles, PGM (2 loci, 4 alleles), IDH (2 loci, 3 alleles), EST (1 locus, 3 alleles), ACP (1 locus, 2 alleles) and MDH (2 loci, 5 alleles). Nine of the 11 loci were polymorphic. A hierarchical ascendant classification (cluster analysis) revealed that the total population was structured into three genetically distinct and diversified groups: A, B and C. The fixation index (F_(st)) and the inbreeding coefficient within sub-population (F_(is)) were found to be +0.20 and -0.15, respectively. The three groups (A, B and C) differ at allele f of the locus Gpi-2 and the alleles e, f and g of the locus Gpi-3. Each group is heterogeneous and contained both Ivorian, Guinean and Nigerian genotypes. The originality of these groups was confirmed by a factorial discriminant analysis. The results led to the conclusion that the three populations studied would have had a common centre of dispersion.