Assessment of Genetic Diversity in Improved and Local Accessions of Okra (Abelmoschus esculentus and Abelmoschus callei) Using RAPD Markers

Aims: The work was conducted to ascertain the level of genetic diversity in some local and improved accessions of okra in Ibadan. This is to contribute to the conservation of plant genetic resources efforts by breeders.

Place and Duration of Study: Improved accessions of okra were collected from National Centre for Genetic Resources and Biotechnology (NACGRAB), Ibadan; National Institute of Horticulture, (NIHORT), Ibadan; and Agronomy Department, University of Ibadan, Ibadan; while local accessions were collected from local farmers in Ibadan between January and June, 2012.

Methodology: Nine accessions of okra (Abelmoschus esculentus and Abelmoschus callei), which cut across improved and local accessions, were assessed for genetic diversity. Genomic DNA was extracted from the 9 okra accessions, and thirteen (13) RAPD markers in the OPB, OPT and OPH series; which exhibited a high level of DNA polymorphism, were used to PCR amplify it (DNA). The PCR products were checked on 1% agarose gel and the banding pattern visualised under UV-light and then photographed. Presence and absence of bands on the gel were scored ‘1' and ‘0' respectively to generate a binary data matrix. Using NTSYS-pc, a pair wise distance matrices was calculated and a dendogram generated by UPGMA cluster analysis.

Results: All the 13 primers used showed polymorphism across the 9 accessions. The genetic similarity of the studied accessions ranged from 76% to 88%. At 88% similarity level 55.6% of the accessions were distinct while 44.4% displayed minimum genetic variation. Maximum genetic variation was observed between A. callei UI accession (an improved accession) and Igala (a local accession).

Conclusion: The accessions displayed genetic diversity. The maximum genetic diversity observed between an improved and local accession, and the minimum genetic diversity observed between two local accessions and two improved accessions shows RAPD markers are still very much useful for genetic diversity study.