Genetic diversity and population structure of Irvingia species using DArTseq generated markers

Irvingia gabonensis and Irvingia wombolu trees indigenous to West and Central Africa are economically important owing to their valuable kernels. Massive fruit harvesting and reduction of forests land area has threatened their genetic diversity thus warranting conservation. This study reports the genetic diversity and population structure based on dominant markers of Irvingia accessions from Nigeria, Cameroon and Gabon held at World Agroforestry field genebanks. A total of 60 samples and 6532 SilicoDArT markers revealed high genetic differentiation among populations (phiPT = 0.301, P = .001). The overall genetic diversity revealed by Nei's gene diversity (He = 0.117) and percentage of polymorphic loci (39.60%) was low. I.gabonensis provenances from Cameroon and Nigeria were more diverse than Gabonese populations. Pairwise phiPT values calculated from AMOVA variances delineated I. wombolu and I. gabonensis. Population structure and cluster analysis based on Bayesian algorithm, DAPC and UPGMA methods placed Cameroon at the center of distribution of I. gabonensis accessions from Nigeria and Gabon. Gabonese accessions tend to cluster independent of Nigerian accessions while I. wombolu formed a distinct cluster from I. gabonensis. SilicoDArT markers were found suitable for population structure and differentiation analysis of Irvingia accessions and can guide future recollections to enrich genebank diversity and materials for domestication events.