PRODUCTION OF COMMERCIAL LILIUM-RUBELLUM BAKER BULBS - EFFECTS OF VOLUME AND RENEWAL OF LIQUID-MEDIUM ON IN-VITRO GROWTH, BULB ROT INFECTION DURING COLD TREATMENT, AND POST-IN-VITRO GROWTH OF BULBLETS

Bulblets of Lilium rubellum Baker were cultured for 16 weeks in a 20-, 30- or 40-ml liquid medium renewed 0, 1, or 3 times. The bulblets wer e assessed for growth and rot infection. 1. Bulblets with fresh weight of more than 600 mg were obtained by using a 20- or 30-ml medium with 3 renewals, or 40 ml with one renewal. 2. Bulblets frequently turned brown when they were cultured in a 30- or 40-ml medium with 3 renewals ; they frequently rotted both during a cold treatment and after transp lantation. 3. Bulblets cultured in a 20-ml medium did not rot after a cold treatment irrespective of the number of medium renewals; they gre w well after transplantation to the greenhouse. 4. Bulblets cultured i n a 20-ml medium with 3 renewals most frequently developed into plantl ets with elongated axes 15 weeks after transplantation. These results indicate that the 20-ml medium with 3 renewals appears to be most suit able for bulblet culture of L. rubellum in a liquid medium.