USE OF MOLECULAR MARKERS IN DEFINING ACKEE (BLIGHIA SAPIDA K.D. KOENIG) DOMESTICATION CENTRES IN BENIN
Ackee (Blighia sapida) is a native multipurpose species important for the livelihoods of rural populations in Benin. Trees are found in natural forests or are managed by farmers in different traditional agroforestry systems. Genetic variation at amplified fragment length polymorphism (AFLP) markers, four nuclear microsatellites (nSSRs) and one chloroplast microsatellite (cpSSR) were investigated in 279 individuals from 6 wild and 8 cultivated populations from Benin. The AFLP data revealed moderate levels of diversity of ackee in Benin (mean diversity values are proportion of polymorphic loci = 52.8% and Neis gene diversity = 0.157, for 375 AFLP fragments). The mean diversity values based on nSSR-markers are expected heterozygosity = 0.286, allelic richness = 2.77. Genetic variation of wild and cultivated populations did not differ markedly. The analysis of molecular variance (AMOVA) revealed that only 7.3 and 5.2% of the variation was partitioned among populations for nSSR- and AFLP-markers, respectively. Mantel tests revealed significant correlations between population pairwise geographic distance and genetic differentiation. Differentiation among cultivated populations was higher than among wild populations. The only polymorphic chloroplast microsatellite marker (ccmp7) showed three haplotypes. Cultivated populations from northeastern Benin were fixed on one haplotype which was not observed elsewhere indicating a different origin of these populations, possibly from neighboring Nigeria. Farmer-led domestication had an impact on the spatial distribution of genetic variation but did not result in significant losses of diversity within populations. Both wild and cultivated populations of ackee are therefore valuable gene pools for breeding and conservation. A multiple breeding population strategy is proposed to move forward with domestication activities. We proposed seven domestication centres (distributed across the country) for germplasm collection and multiplication in order to provide good quality planting materials for farmers.
Ekué, M.R.M. and Finkeldey, R. (2013). USE OF MOLECULAR MARKERS IN DEFINING ACKEE (BLIGHIA SAPIDA K.D. KOENIG) DOMESTICATION CENTRES IN BENIN. Acta Hortic. 979, 499-507
AFLP, nuclear and chloroplast microsatellites, genetic structure, human impact, agroforestry, breeding