Chromosome Numbers of Four Nigerian Species of Cola Schott. & Endlicher (Sterculiaceae).

This paper reports the results of chromosome countings in four wild Cola species (Cola lateritia, C. ballayi, C. verticillata and C. gigantea). Cytological investigation of these species gave a constant mitotic chromosome counts of 2n = 4x = 40 for the first time. The karyotypes were found to consist mostly of metacentric and submetacentric chromosomes. In addition to confirming the chromosome numbers and ploidy levels in these species, the results also reveals high symmetry and homogeneity of the karyotypes with those of the cultivated species (C. nitida and C. acuminata) already reported. The similarity in chromosome morphology between the cultivated and wild species indicate their common origin and suggests the possibility of using these wild species as bridges for gene transfer in Cola breeding programmes involving interspecific hybridization.