Abstract:
This study assessed the extent and distribution of genetic diversity of 29 Faidherbia
albida provenances from 10 African countries by employing amplified fragment length
polymorphism with an aim of providing crucial genetic diversity information for in situ
and ex situ management and utilization of the collections. Plant materials consisted of
F. albida accessions held at World Agroforestry Centre [International Center for
Research in Agroforestry (ICRAF)] seed bank. A total of 676 bands ranging from 50 to
499 base pairs were scored using five primer sets. The average percentage of
polymorphic loci over all populations was 31.7. The collection from the Taveta
(Kenya) provenance had the highest percentage of polymorphic loci (69.5%), while
those from Manapools (Zimbabwe) had the lowest (13.5). The average heterozygosity
ranged from 0.05 to 0.28 with a mean of 0.16 across all the provenances. There was
high and quite significant population differentiation among the populations
(PhipT ¼ 0.64, p ¼ 0.001). Analysis of molecular variance revealed that 64% of the
total variation was partitioned among the populations and 36% within the populations.
Unweighed pair-group method with arithmetic averaging clustering generally reflected
the geographical origins and similarity of the germplasm except West African
provenances indicating complex evolutionary trends that have shaped the population
structure and distribution of the species. The results show that the germplasm held at
ICRAF seed bank is of low genetic variability with the western and some of the eastern
Africa provenances having the highest diversity. More collections need to be done to
cover the entire distribution range of this species to capture more diversity and enrich
this gene pool.
