Germination ofGarcinia kola(Heckel) seeds in response to different hormone treatments

Abstract

Introduction. Despite its socio-economic importance, cultivation of Garcinia kola Heckel is very limited due to poor seed germination. The literature gives contradictory information concerning this fact. Our study therefore aimed at (1) evaluating the variability in germination traits among seeds collected from different areas of Cameroon; and (2) testing the efficiency of some hor- mone treatments in improving the seed germination rate, which would promote cultivation of G. kola by rural farmers. Materials and methods. Six collections of seeds originating from six locations in Cameroon were subjected to pre-sowing treatments; soaking for 3 days at room tem- perature in cool distilled water (control), or in cool distilled water supplemented with either 10 -4 M gibberellic acid (GA3), 10 -4 M naphthalene acetic acid (NAA), 10 -4 M 2,4-dichlorophenoxyacetic acid (2,4-D), 10 -4 M benzylaminopurine (BAP) or 10 -4 M kinetin; they were then placed to germi- nate in laboratory conditions. Cumulative seed germination data were recorded for 30 weeks. Results. The pre-germination treatments had profound effects on the phenology of G. kola seed germination. Multiple shoots, multiple roots and callus formation were induced from seeds soaked in BAP, NAA and 2,4-D solutions, respectively. Analysis of variance showed a significant effect (p < 0.01) of seed collection on the germination velocity. Although the rate of germination was higher and the complete dormancy period lower in seeds treated with NAA than in seeds with other treatments, none of these seed treatments significantly enhanced germination. Conclusion. Varia- tions in phenology responses of G. kola seeds to hormone treatments indicate that the tissues of this plant may be responsive in in vitro culture. Variations in seed germination velocity among col- lections may explain the current controversy over G. kola seed germination, and could help in fur- ther selection and domestication processes of this species. Cameroon / Garcinia kola / plant propagation / seeds / dormancy breakers / germination / plant growth substances Germination des graines de Garcinia kola (Heckel) en reponse a differents traitements hormonaux.