Genetic diversity and population structure in a regional collection of Kersting’s groundnut (Macrotyloma geocarpum (Harms) Maréchal & Baudet)

Abstract

Kersting’s groundnut (Macrotyloma geocarpum (Harms) Marechal & Baudet) is an important source of protein and essential nutrients that contribute to food security in West Africa. However, the crop is still underexploited by the populations and under-researched by the scientific community. This study aimed to investigate the genetic diversity and population structure of 217 Kersting’s groundnut accessions from five origins using 886 DArTseq markers. Gene diversity was low and ranged from 0.049 to 0.064. The number of private alleles greatly varied among populations (42–192) and morphotypes (40–339). Moderate to very high levels of selfing and inbreeding were observed among populations (s = 56–85%, FIS = 0.389–0.736) and morphotypes (s = 57–82%, FIS = 0.400–0.691). Moreover, little to very high genetic differentiations were observed among populations (0.006 ≤ FIS ≤ 0.371) and morphotypes (0.029 ≤ FIS ≤ 0.307). Analysis of molecular variance partitioned 38.5% of the genetic variation among and 48.7% within populations (P < 0.001). Significant isolation by distance was detected between populations (R2 = 0.612, P = 0.011) and accessions (R2 = 0.499, P < 0.001). Discriminant analysis of principal components and neighbour joining consistently distinguished eight distinct clusters. These data provide a global picture of the existing genetic diversity for Kersting’s groundnut and will guide the choice of breeding strategies to increase production.