IN-VITRO PROPAGATION AND POST-IN-VITRO ESTABLISHMENT OF BULBLETS OF LILIUM-JAPONICUM THUNB

Lilium jeponicum growing in the experimental field were collected in e arly May and segments of their scales, leaves and stems of the plants were cultured in vitro on a basal medium consisting of Murashige and S koog's inorganic salts (1962) supplemented with several organic nutrie nts. Young leaf-segments were a suitable source for propagation, becau se they were least contaminated and almost had the same capacity as sc ale seg ments for bulblet regeneration. Bulblets were proliferated by culturing whole scales or segments on the basal medium supplemented wi th 0.1 mg . liter(-1) NAA and 0.01 mg . liter-1 BA. A cold treatment a t 4 degrees C for more than 12 weeks broke the dormancy of in vitro cu ltured bulblets. In vitro light conditoin affected both post-in vitro bulblet-rot infection and plant growth in soil. The bulblets incubated in the dark were more susceptible to soil-born organisms than were th ose incubated in the light. Nearly all the bulblets of more than 400 m g in weight grew into plants with elongated axes (epigeous type plant; ETP). The ETP plantlets required at least 2 years' cultivation before they flowered.