In vitro bulb formation of direct and indirect regeneration of Lilium orientalis cv. “Starfighter” plants

Abstract

Abstract Background Lily is one of the most important commercial cut flower species and one of the three major bulb crops in the commercial market. The aim was to assess and establish a suitable protocol for increasing the number of Lilium bulblets and enlarge their size. Methodology Different plant growth regulators (TDZ, 2,4-D, 2ip, and picloram) at different concentrations for direct and indirect micropropagation were used. Also, the effect of various concentrations of sucrose alone or with growth inhibitor on bulblet formation during three repeated subcultures was examined with anatomical study. Results For direct shoot organogenesis, culturing leaf explant on MS culture medium containing TDZ (0.5 mg/l) + 2,4-D (10 mg/l) led to the highest number of shootlets after 1 month. For indirect micropropagation, MS was supplemented with 2ip (0.5 mg/l) + picloram (5 mg/l)-induced callus tissues which were differentiated to embryos then weak shoots after 3 months. For more proliferation, the highest numbers of shootlets, leaves, and bulb scales were observed on MS culture medium supplemented with 1.0 mg/l of BA plus 0.2 mg/l NAA. Using 60 g/l of sucrose plus 3 or 6 mg/l of paclobutrazol led to the highest number of bulblets/explant for the third subculture. The highest bulblet diameters were recorded with 120 g/l sucrose plus 6 or 3 mg/l paclobutrazol. Conclusion This study had reached to optimize a suitable protocol for direct and indirect micropropagation of Lilium orientalis cv. “Starfighter” bulbs and increase the number and size of bulbs that can be beneficial for increasing the production and reduce their price. This study will help the producers for commercial purposes.

Keywords

• Lilium
• Micropropagation
• Bulblet formation and anatomy