Maturation, Enlargement and Breaking Dormancy of In Vitro Lilium Bulblets

One of the most effective ways for propagation of Lilium is using tissue culture techniques, preferably through bulblet production. In addition of surviving percentage of Lilium bulbs after transplantation, the small size of in vitro bulblets compared to commercial bulbs and bulbletʹs dormancy are the most important constraints to commercialize Lilium micropropagation. Different concentrations of sucrose or sorbitol as carbohydrate sources were investigated as maturation and enlargement factors on in vitro bulblets of Lilium longiflorum cv. ‘Ceb-dazzle’. Five concentrations of gibberellic acid and 4°C cold treatment for 6, 7, 8, 9, 10 and 11 weeks in the greenhouse were studied on dormancy breaking of three in vitro Lilium bulblets cultivars, ‘Simplon’, ‘Navona’ and ‘Ceb-dazzle’ belonging to Oriental, Asiatic and LA hybrids. The results showed that 3% of sucrose and a period of 2 weeks culture significantly increased bulblet maturation and enlargement of ‘Ceb-dazzle’. One mg L-1 gibberellic acid, for 6 weeks or cold treatment for 6-8 weeks had significant positive effects on dormancy breaking of in vitro bulblets of Lilium cultivars.