In vitro and ex vitro growth of micropropagated Lilium longiflorum Thunb. bulblets

Micropropagated bulblets of Lilium spp. are susceptible to high loss when cultured ex vitro. The behavior of these bulblets after in vitro and ex vitro growth periods was studied to evaluate the effectiveness of in, vitro treatment on improving bulblet size and biomass. Micropropagated bulblets of Lilium longiflorum cv. 'Snow Queen' were subcultivated in vitro for one, 2, 3, 4, or five months, with a complementary period in soil for a total of six months cultivation. Other micropropagated bulblets were cultivated directly in soil for one, 2, 3, 4, 5 or six months. Bulblets' fresh and dry mass increased during in vitro growth, reaching an average fresh mass of 1.2 g by the end of the 5(th) month, while pot-cultivated bulblets averaged 0.7 g, Survival of in vitro treated bulblets was about 98% compared to about 70% for untreated bulblets. Bulblet mass also strongly influences the sprouting pattern. Treatment including 3 months of in vitro growth plus 3 months of growth in pots shows considerable advantage over other treatments because of the larger proportion of plants with aerial shoots. Results suggest 3 months in vitro subcultivation as a practical approach for obtaining bulblets with larger biomass, better survival, easier handling and superior overall field performance.