Molecular and Morphological Diversity Studies of Five Cola (Schott and Endl.) Species in Ibadan, Nigeria

Abstract

Intra- and inter-species genetic diversity study was carried out comparing the molecular and morphological characters of five Cola species namely Cola acuminata, Cola nitida, Cola millenii, Cola lepidota and Cola gigantea collected from five locations in Ibadan, Nigeria. Sixteen Cola accessions were analysed based on 7 quantitative characters, 12 qualitative characters and 8 Random Amplified Polymorphic DNA primers. From the quantitative characters studied, high significant difference across the location and species was recorded as leaf length had the strongest variability while the species obtained from Botany Nursery showed strongest locational effect on the vegetative leaf characters. All quantitative characters analysed were good determinants for delimiting Cola species. Cola lepidota recorded the highest variability compared to the other Cola species. Qualitative characters studied revealed that leaf surface, seed colour, and floral colour are strong characters for delimiting Cola species. Molecular analysis showed that 309 fragments were recorded, of which 28.5% were polymorphic while 8.4% were monomorphic. Genetic similarities ranged from 0.44 to 0.93 for the 16 Cola accessions with a mean value of 0.67. Deductions from the combined effect of molecular and morphological characters showed high variability for the characters analysed and a likely monophyletic relationship for the 16 Cola accessions.  Molecular and morphological determinants observed in this study can help Cola breeders identify species of interest. We recommend further research on the variability of Cola species.