Sources of Genetic Variation in Faidherbia albida (Del.) A. Chev. Sub-Saharan African Populations

The adaptation of Faidherbia albida (Del.) A. Chev. to drought conditions, its reverse phenology, ability to improve soil fertility, importance as source of forage, and its medicinal properties make it an excellent tree for Sub-Saharan African communities. However, there has been little effort to develop improved genotypes of F. albida, in part because there is relatively little information about phenotypic and genetic variation within this species. This study’s aim was to characterize the genetic diversity of F. albida among Sub-Saharan natural populations with the goal of identifying material for the improvement of the species in Cameroon and other African countries. We genotyped seven simple sequence repeat (SSR) loci in 267 individuals, 15 populations, and 8 countries in Sub-Saharan Africa representing the range of distribution of F. albida. A total of 32 alleles were identified. The highest level of polymorphism was found in Senegal and Ethiopia. Structure analysis of allelic distributions differentiated the 15 populations into three clusters representing West, East, and South Africa. However, one population in Ethiopia (Rama) was strikingly similar to the West Africa cluster. Genetic diversity decreased from West and East Africa to South Africa. These results support the hypothesis that F. albida originated in West or East Africa and subsequently spread to South Africa. Further sequence-based genotyping of these and additional populations will provide an accurate picture of the origin and subsequent spread of this species and reveal new sources of genetic variation for its improvement.