Assessment of Genetic Diversity among Newly Selected Roselle (Hibiscus sabdariffa Linn.) Genotypes in Nigeria Using Rapd-Pcr Molecular Analysis

Abstract

In order to assess the genetic diversity among Nigerian Roselle (Hibiscus sabdariffa Linn.), certain genetic and morphological markers were used to group the various accessions collected into distinct genotypes. Molecular characterisation was then conducted on the twenty newly selected genotypes (NGR-HS-001, NGR-HS-002, NGR-HS-003, NGR-HS-004, NGR-HS-005, NGR-HS-006, NGR-HS-007, NGR-HS-008, NGR-HS-009, NGR-HS-010, NGR-HS-011, NGR-HS-012, NGR-HS-013, NGR-HS-014, NGR-HS-015, NGR-HS-016, NGR-HS-017, NGR-HS-018, NGR-HS-019, and NGR-HS-020) of the Roselle (H. sabdariffa Linn.), using Random Amplified Polymorphic DNA-Polymerase Chain Reaction (RAPD-PCR) based techniques. The molecular characterisation was carried out at the Biotechnology Laboratory, International Institute of Tropical Agriculture (IITA), Ibadan. Five RAPD primers i.e. OPH05, OPB17, OPT17, OPB11 and OPB04 were able to amplify 30 reproducible fragments of which 100 % were polymorphic, indicating that Nigerian Roselle accessions are genetically heterogeneous; it also showed that RAPD analysis is an effective molecular marker in detecting genetic diversity among different Roselle genotypes in Nigeria. All the primers gave a high genetic diversity and high polymorphic information contents, however, OPT17 gave the highest genetic diversity and polymorphic information content (0.79 and 0.78 respectively). The Dice Dissimilarity index for the calculation of distances among the roselle accessions revealed an interesting phenomenon because a clear divergence among the H. sabdariffa accessions was found. The dissimilarity index ranged from 0-1, which revealed a wide range of genetic identity. Dissimilarity coefficient of accession NGR-HS-017 was the highest (1.00); this accession was totally different or genetically distance from all the other accessions. In addition, a high dissimilarity index (1.00) was also obtained among some of the accessions; NGR-HS-018 was highly dissimilar from NGR-HS-002, NGR-HS-012 and NGR-HS-016. However, a quite number of the accessions showed moderately low to zero dissimilarity indices. It is therefore concluded that RAPD-PCR analysis provided very valuable means for determining relationships among H. sabdariffa accessions. Wide genetic variability observed among the Roselle accessions could be exploited in different breeding programs of the crop. Therefore, other DNA markers like SSR and RFLP should be used to ascertain these levels of relationships.