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 hormone 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 temperature 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 germinate 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. Variations 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 collections may explain the current controversy over G. kola seed germination, and could help in further selection and domestication processes of this species.

Introduction. In subtropical regions, the lack of or insufficient winter chilling has been one of the most important yield-limiting factors for table grapes. Winter chilling for several weeks is required to cause the transition of both vegetative and floral buds from the dormant to the active state. Thus, the effect of time of application of Dormex® (hydrogen cyanamide) on fruit quality and ripening of ‘Superior’ seedless grape was evaluated under Jordan Valley conditions.Materials and methods. Five-year-old ‘Superior’ seedless vines were pruned on 20 December and sprayed to run-off with a 5% (v/v) concentration of Dormex® at pruning (Dormexprun0), 7 d (Dormexprun7) or 14 d (Dormexprun14) after pruning in comparison with the pruned-only control plants. The date of vegetative budbreak and start of flowering were determined. Fruits were harvested at intervals of 7 d starting from 9 May, with four harvests. Studied data were fruit weight, total soluble solids (TSS), titratable acidity (TA) and maturity with the [TSS:TA] ratio. Results and discussion. All pruned and sprayed vines broke bud 23–46 d after pruning. The (Dormexprun0) and (Dormexprun7) treatments were the earliest. Compared with the control, Dormex®-treated vines broke bud 4–26 d earlier. All pruned and Dormex®-treated vines started flowering 55–64 d after pruning, with 4–13 d earlier than the control. Fruits of the (Dormexprun0) treatment had significantly the highest fruit weight, TSS and the least TA, and it was the only treatment that exceeded the [18:1] (TSS:TA) level. Additionally, higher TSS and lower TA were observed for fruits of Dormex®-treated vines during all harvest dates in comparison with the control. Conclusion. Our study showed that, under southern Jordan Valley conditions, Dormex® should be applied as early as at pruning time to obtain early budbreak and maturity.