A practical method for the production of flowering Easter lilies from callus cultures

Callus cultures were established from immature leaf explants of Easter lily (Lilium longiflorum Thunb. cv. 'Nellie White'). These callus cultures were induced to undergo organogenesis within 3 weeks upon subculture to medium containing 0.1 mg l^-1 of both 2,4-dichlorophenoxyacetic acid and 6-benzylaminopurine. The regenerated plantlets were acclimatized under a mist and transferred to greenhouse conditions at a 100% success rate. Plants exposed to supplemental lighting produced an average of four flowers per plant, were 20 cm shorter and flowered six and a half weeks sooner than plants maintained under normal day length conditions, where only 63% of the plants flowered. On average, plants supplied with supplemental lighting required 29 weeks (8 weeks of acclimation, 9 weeks in 15 cm pots under normal greenhouse conditions, and 12 weeks under supplemental lighting) from the time of establishing in the greenhouse to full bloom. The number of abnormal plants observed was less than 2%. Maintaining plants in 6 cm × 4 cm × 5.5 cm growing trays produced miniature Easter lily plants, each with a single flower.