3.1. Population structure and admixture
Despite low levels of diversity
(He = 0.28 and Ho = 0.023, p.value = < 0.001), Kersting’s
groundnut populations remained genetically well differentiated.
Admixture models with a putative number of tested genetic clusters (K)
from one to five, showed that the most likely number of inferred members
was 2 with ΔK = 368.369 (Figure 1a). The classification of the 361
accessions into populations based on the model-based structure (Figure
1b) showed that 231 accessions belonged to the first population (Pop1)
and 130 accessions were included in the second population (Pop2). Table
1 showed the distribution of populations across agroclimatic zones. Most
of the accessions were collected in the Southern-Sudanian zone with
proportions of 80.519% and 80% comprised in Pop1 and Pop2,
respectively. The accessions collected in Northern-Sudanian zone were
all counted in the Pop2. In the Northern-Guinean zone, 19.481% of
accessions belonged to Pop1 and 14.615% were included in Pop2.The
random distribution of landraces (Figure 2) into the genetic groups
indicated that Pop1 were mostly characterized by the White landrace
(97.403% of individuals in Pop1). Pop1 comprised also the Red and the
Black landraces. Pop2 were composed of all the six landraces included in
this study with a predominance of Black (43.846%) and Brown ones
(30%).
The analysis of genetic distance revealed relatively strong genetic
differentiation among the two distinct groups of KG with pairwise Fst
value of 0.704 (Table 2). The estimates values of gene diversity (Hs)
showed overall, low genetic divergence between individuals within each
Group. Meanwhile, the heterozygosity analysis showed a greater genetic
divergence between individuals in Pop2 (Hs = 0.323).