Exploring the genetic diversity using CAAT box-derived polymorphism (CBDP) and start codon targeted (SCoT) markers in cultivated and wild species of okra (Abelmoschus esculentus (L.) Moench)

Okra is a warm season vegetable with excellent nutritional, medicinal and industrial potential. In this study, we have employed 25 CAAT box-derived polymorphism (CBDP) and 36 start codon targeted (SCoT) markers to assess the genetic diversity among 89 accessions belonging to cultivated and wild species of okra. Out of the total 61 primers, 27 primers (20-CBDP and 7-SCoT) were amplified with distinctly discernible amplicons of 350–1500 bp and 200–3000 bp respectively. Polymorphic information content (PIC) had average values of 0.28 and 0.20 and average marker index (MI) of 2.40 and 3.18 per primer for CBDP and SCoT primers respectively. The resolving power (Rp) produced an average of 3.70 per primer for CBDP and 4.05 per primer for SCoT markers. Nei's genetic diversity ( h ), for CBDP was 1.7 while 0.13 for SCoT. Analysis of molecular variance (AMOVA) revealed 11% and 24% variance among the populations and 89% and 76% variance within the populations for CBDP and SCoT primers respectively. Principal Coordinates Analysis (PCoA) displayed 79.82% and 82.72% of the variation for CBDP and SCoT primers respectively. UPGMA hierarchical dendrogram based on Jaccard's similarity divided the accessions into several clades, with a considerable grouping of cultivated accessions in one clade and wild population in the other. A Bayesian model STRUCTURE analysis of Abelmoschus populations based on CBDP and SCoT markers, produced two (K = 2) and four (K = 4) genetic structures, respectively, with little admixture. In this study, the CBDP markers performed better than the SCoT markers for estimating genetic diversity among cultivated and wild okra accessions.