In vitro regeneration of fancy-leaved Caladium x hortulanum birdsey cultivars from leaf petiole explants

The direct regeneration of new mini tubers from leaf petiole explants of various cultivars ('Candidum', 'Miss Muffet', 'Ivory1, 'Carolyn Whorton', 'White Christmas', 'Frieda Hemple' and 'Gypsy Rose') of Caladium x hortulanum Birdsey and effect of growth regulators were studied using basal Murashige and Skoog medium containing inorganic salts and vitamins at full strength. The cultures were incubated at 25°C, 16-h photoperiod (daylight fluorescent tubes, 80 W) and were grown for 12 weeks in 200 ml glass flasks each containing 25 ml of medium and 10-12 petiole explants. No regeneration occurred if explants were incubated on MS medium without growth regulators. Auxin and cytokinin supplement was indispensable for mini tubers formation from leaf petiole explants. It was found that different cultivars showed different responses to the same culture medium. Bulblets formation on leaf petiole explants of Caladium cultivars strongly depended on the hormone concentration in the medium. Both auxin and cytokinin must be present in very specific combinations, and cytokinin content must be higher than that of auxin. Regeneration efficiencies were found to be highly dependent on the cultivar. Shoot buds transferred to Murashige and Skoog medium grew vigorously and rooted with 100% efficiency, and plants showed normal growth under greenhouse conditionsVytauto Didžiojo universitetasŽemės ūkio akademij