Allanblackia floribunda: a new oil tree crop for Africa: amenability to grafting

Abstract

Three Allanblackia species (A. floribunda, A. stuhlmannii and A. parviflora) with high nutritive, medicinal, cosmetic and economic values are currently being domesticated as new oil tree crops. Allanblackia seeds contain a hard white fat consisting mostly of stearic (52-58%) and oleic (39-49%) acids. This unusual fatty acid content has the right properties for many different food and cosmetic products making them commercially interesting. Vegetative propagation studies on A. floribunda, which grows naturally in the moist forest of Cameroon and Nigeria, were initiated aimed at evaluating its amenability to grafting. Scions were grafted onto 18 month old rootstocks of A. floribunda using side tongue, top cleft, side veneer, whip-and-tongue methods under nursery conditions in Cameroon. In parallel, side tongue and inverted'T' budding methods were also tested in situ on young A. floribunda wildings growing under semi-deciduous and evergreen tree covers. In addition, the effects of protecting side tongue new grafts with non perforated translucent plastic, perforated translucent plastic and aluminium foil were assessed. Under nursery conditions, side tongue grafts were significantly more successful (80.0 ? 6.3%), than grafts of side veneer (52.5 ? 7.9%), top cleft (55.0 ? 7.9%) and whip and tongue (50.0 ? 7.9%). The success of side tongue graft was further increased (86.7 ? 6.2%) under the shade of evergreen trees when protected by non perforated translucent plastic. These results indicate the potential for in situ grafting and'top working' to promote cultivation of more productive germplasm of Allanblackia within multifunctional agricultural systems