Micropropagation of poinsettia by organogenesis.

Poinsettia (Euphorbia pulcherrima) is one of the most popular ornamental pot plants. Conventional propagation is by cuttings, generally focused on a period prior to the most intensive time of sales. Rapid multiplication of elite clones, the production of pathogen-free plants and more rapid introduction of novel cultivars (cvs.) with desirable traits, represent important driving forces in the poinsettia industry. In recent years, different strategies have been adopted to micropropagate poinsettia, which could assist breeders to meet consumer demands. The development of reliable in vitro regeneration procedures is likely to play a crucial role in future production systems. Stem nodal explants cultured on semi-solid MS-based medium supplemented with benzylaminopurine (BAP) and naphthalene acetic acid (NAA) develop shoots from adventitious/axillary buds after 7 weeks of culture. Rooting of in vitro regenerated shoots is achieved in semi-solid MS-based medium containing the auxin indole-3-acetic acid (IAA). Four to six weeks after transfer to root-inducing medium, regenerated plants can be transferred to compost and acclimatized in the glasshouse. Direct shoot regeneration from cultured explants is important to minimize somaclonal variation in regenerated plants.