Micropropagation of the River Lily, Crinum variabile (Amaryllidaceae)

Crinum variabile (Jacq.) Herb. is restricted to the Namaqualand, Bokkeveld Mountains and western Karoo regions of South Africa. Although its potential as a horticultural subject has been recognised, factors relating to the biology of the plant limit large scale propagation. These include short-lived seed viability and vegetative offsets that are produced too slowly or infrequently. As an alternative to conventional methods, C. variabile was successfully propagated in vitro using twin-scale explants. Shoots developed in the axes of twin-scales when placed on a Murashige and Skoog (MS) medium. Plant growth regulators were not required for the induction of shoots but benzyladenine (BA), in the absence of naphthalene acetic acid (NAA), promoted their outgrowth. The inclusion of 5gl(-1) activated charcoal improved development by increasing the bulblet size and frequency with which shoots formed bulblets. These bulblets were used to initiate further cultures by splitting them in half. Such a system provided for the continuous multiplication of C. variabile bulblets which readily transferred to the soil.