Clonal Propagation of Coconut: Improved Culture Conditions for Rhyzogenesis

Emphasis has recently been placed on improving culture conditions at the rootingstage of the coconut (Cocos nucifera L) cloning prooedure. In these experimentsshoots for rooting were obtained by culturing shoot apices.The effect of auxins (IAA, NAA, IBA), carbohydrate sources (glucose, fructose,sucrose), lighting'conditions and dark treatment on rooting were tested. Diptreatment of shoots in 10"* M IAA solution for three to seven days followed bytransfer to auxin free medium produced the best rooting (62.5%). Addition ofglucose at 60 gl"1 into the culture medium as the carbohydrate source increased therooting percentage (71.4%) and stimulated secondary root formation. Sucrose at 60gl"1 produced a higher number of primary roots per shoot (4.4) compared to rootsper shoot in the 60 gl'1 glucose treatment (2.3). Exposure of shoots to an initialseven-day dark period and localized lighting had a positive effect on rooting.These findings can now be applied to obtain .better rooting not only, in clonalplants but also in zygotic embryo cultured plants.