Domestication of Allanblackia floribunda: Amenability to vegetative propagation

Allanblackia floribunda is a wild and undomesticated forest tree species valued for its nuts used in the food and cosmetic industry. To initiate domestication in the species, the amenability of A. floribunda to vegetative propagation was examined through the rooting of single-node leafy stem cuttings using non-mist propagators in Cameroon. Sixty-four cuttings from each of four tested clones (MB, NG1, NG2, NG4) were set in each of four replicate blocks arranged in a randomised split-split plot factorial design. Each main plot was randomly divided into two types of rooting medium (sand or a 50:50 mixture of sand/sawdust). Sub-plots received three types of auxin at 50 μg per cutting (IAA, IBA or NAA) dissolved in 10 μl of alcohol, the control receiving 10 μl of alcohol. Sub-sub plots had four cutting leaf areas (0, 12.5, 25 and 50 cm2). Interaction of these factors was also investigated. Clone × substrate (variance = 0.01706) and clone × substrate × leaf area (variance = 0.00835) interactions were identified as important factors on rooting of A. floribunda single-node cuttings at week 38. Rooting medium, clone and leaf area had highly significant effects (p < 0.001). Application of auxin did not enhance rooting percentage in cuttings by the end of experiment. Optimising important factors (substrate, clone and leaf area) for rooting identified best rooting percentages (68.7%) in leafy cuttings from clone MB in sand. None of the tested factors had significant effects on number of roots, and rooted cuttings had on average one root. These results indicate that A. floribunda is difficult to root, but is amenable to vegetative propagation. Further work is required to achieve good rooting, as this study indicated that good rates of rooting can be achieved when important factors are optimised.