<i>In vitro</i> propagation of <i>Paphiopedilum</i> orchids

<p><i>Paphiopedilum</i> is one of the most popular and rare orchid genera. Members of the genus are sold and exhibited as pot plants and cut flowers. Wild populations of <i>Paphiopedilum</i> are under the threat of extinction due to over-collection and loss of suitable habitats. A reduction in their commercial value through large-scale propagation <i>in vitro</i> is an option to reduce pressure from illegal collection, to attempt to meet commercial needs and to re-establish threatened species back into the wild. Although they are commercially propagated <i>via</i> asymbiotic seed germination, <i>Paphiopedilum</i> are considered to be difficult to propagate <i>in vitro</i>, especially by plant regeneration from tissue culture. This review aims to cover the most important aspects and to provide an up-to-date research progress on <i>in vitro</i> propagation of <i>Paphiopedilum</i> and to emphasize the importance of further improving tissue culture protocols for <i>ex vitro</i>-derived explants.