Micropropagation of orchids: A review on the potential of different explants

Orchids are among the most diverse of the flowering plant families, with over 800 described genera and 25,000 species. Orchids are prized for their beautiful long lasting flowers exhibiting an incredible range of diversity in size, shape and colour. Today growing orchids is more than just a hobby, it is an international business covering around 8% of the world floriculture trade and has the potential to alter the economic landscape of a country. Large-scale multiplication of exquisite and rare hybrids using tissue culture techniques has helped orchids occupy a position as one of the top ten cut flowers. As orchids are outbreeders, their propagation using seeds leads to the production of heterozygous plants. Hence, protocols providing regeneration from various vegetative parts of the plants are needed. Though orchid micropropagation has shown spectacular development in the recent years, the wide spread use of micropropagation is believed to be still limited due to problems like exudation of phenolics from explants, transplantation to field, somaclonal variation etc. We endeavour to include the major investigations on explant-based orchid tissue culture starting from the pioneering works of Rotor I Rotor, G., 1949. A method of vegetative propagation of Phalaenopsis species and hybrids. Am. Orchid Soc. Bull. 18,738-739] followed by Morel [Morel, G., 1960. Producing virus-free cymbidiums. Am. Orchid Soc. Bull. 29, 495-497] and Wimber [Wimber, D.E., 1963. Clonal multiplication of cymbidiums through tissue culture of the shoot meristem. Am. Orchid Soc. Bull. 32, 105-107] to date. (C) 2009 Elsevier B.V. All rights reserved.