CLONAL PROPAGATION OF COCONUT: IMPROVED CULTURE CONDITIONS FOR RHYZOGENESIS

Abstract

Emphasis has recently been placed on improving culture conditions at the rooting
stage of the coconut (Cocos nucifera L) cloning prooedure. In these experiments
shoots 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. Dip
treatment of shoots in 10"* M IAA solution for three to seven days followed by
transfer to auxin free medium produced the best rooting (62.5%). Addition of
glucose at 60 gl"1 into the culture medium as the carbohydrate source increased the
rooting percentage (71.4%) and stimulated secondary root formation. Sucrose at 60
gl"1 produced a higher number of primary roots per shoot (4.4) compared to roots
per shoot in the 60 gl'1 glucose treatment (2.3). Exposure of shoots to an initial
seven-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 clonal
plants but also in zygotic embryo cultured plants.