Establishment of tissue culture and regeneration system for Lilium ‘Regression’

Objective The Lilium ‘Regression’ has extremely high economic and ornamental values. Establishing an efficient tissue culture system for it is of great importance. This study aims to integrate the high efficiency of scales and the sustainability of leaves to construct a regeneration system for Lilium ‘Regression’ via the callus tissue pathway, providing technical support for its genetic transformation and new variety breeding.

Method Using scales and leaves of Lilium ‘Regression’ as explants, the optimal callus induction medium was screened. The effects of different 6-BA concentrations on adventitious bud differentiation, different sucrose concentrations on bulblet swelling, different activated carbon concentrations on rooting were investigated, and tissue culture seedling transplantation experiments were carried out.

Result (1) The suitable callus induction medium for scales of ‘Regression’ lily was MS + 1.0 mg/L PIC + 0.5 mg/L TDZ, with an induction rate of (60.98 ± 13.90)% and a callus area of (0.62 ± 0.23) cm². The suitable callus induction medium for leaves of ‘Regression’ lily was MS + 2.0 mg/L PIC + 0.2 mg/L TDZ, with an induction rate of (36.83 ± 1.89)% and a callus area of (0.34 ± 0.08) cm². There were differences in callus formation and development between different explants, among which the scale explants had better effects on callus induction. (2) The MS medium containing 1.0 mg/L 6-BA and 0.2 mg/L NAA had optimal effects on adventitious bud differentiation from callus, with a callus differentiation rate of 100% and a bud regeneration coefficient of 8.20 ± 0.60. Adding 90 g/L sucrose to the MS medium promoted the mass growth of bulblets. In root development stage, the MS medium containing 0.2 mg/L NAA and 2 g/L activated carbon was the optimal rooting medium, and the transplantation survival rate was as high as 96.00%.

Conclusion This study successfully established an efficient induction and regeneration system for callus tissue of Lilium‘Regression’, achieving full-cycle optimization from callus induction to seedling transplantation. The research results will lay foundation for genetic transformation and new variety promotion of Lilium‘Regression’ .