Competency assessment of directed amplified minisatellite DNA and start codon targeted markers for genetic diversity study in accessions of Vigna subterranea (L.) Verdcourt

Assessment of genetic diversity of Bambara groundnut (Vigna subterranea (L.) Verdcourt) accessions from Nigeria using informative molecular markers has become imperative for their genetic improvement and conservation. Comparative analysis of 30 V. subterranea from different locations in Nigeria was investigated using Directed Amplified Minisatellite DNA (DAMD) and Start codon targeted (SCoT) markers. The DNA was extracted using CTAB method for amplification. Both markers resolved the accessions into eight major groups using dendrograms and six clusters by principal component analysis. Alleles of 25 and 53 were obtained with DAMD and SCoT, respectively. Mean alleles, gene diversity, and polymorphic information content detected with DAMD were 10.2000, 0.6950, and 0.6600, while SCoT yielded 16.200, 0.847, and 0.836, respectively. Polymorphic loci were 130 and 142 in DAMD and SCoT, respectively. Both markers produced high polymorphism of 60.00-80% and 40.33-96.67% in DAMD and SCoT, respectively. Effective alleles (Ne) in both markers (DAMD: 1.1828-1.5927; SCoT: 1.1830-1.6779) were high. The Nei’s value (H) ranged from 0.1959-0.3238 in DAMD and 0.1533-0.3782 in SCoT. The Shannon’s information index (I) obtained from DAMD and SCoT were 0.3281-0.4635 and 0.1420-0.5557, respectively. Total gene diversity (Ht), diversity within population (Hs), coefficient of gene differentiation (Gst), and estimate of gene flow (Nm) from DAMD were 0.3304, 0.2673, 0.1907, and 2.1215, while SCoT had 0.3927, 0.3163, 0.1945, and 2.0713, respectively. Our study demonstrated that SCoT markers are more competent than DAMD and should be integrated in the exploration of genetic diversity and selection of unique accessions for improvement and utilization of V. subterranea.