Micropropagation of Lisianthus (Eustoma grandiflorum (Raf.) Shinn.) Using Meta-Topolin

Lisianthus (Eustoma grandiflorum) is an ornamental species of high commercial value due to its diverse flower colors and prolonged vase life. However, lisianthus propagation by seed is limited by its low germination rates and high genetic variability, compromising plant uniformity and production timelines. This study evaluated the effect of meta-Topolin (mT) and of 6-benzylaminopurine (BAP), aromatic cytokinins, on the in vitro micropropagation of lisianthus, aiming to develop an efficient protocol for mass propagation. In vitro established shoots were cultured on Murashige and Skoog (MS) medium supplemented with different concentrations of mT and BAP (0, 0.5, 1.0, or 1.5 mg L^-1). The parameters assessed were shoot proliferation, shoot length, leaf number, root formation, and root length. Significant differences were observed among treatments. The highest proliferation rate (59.20 shoots per explant) was achieved with 0.5 mg L^-1 mT, representing a 37-fold increase over the control. With the addition of BAP to the culture medium, the results were inferior. Higher mT concentrations promoted rooting and improved acclimatization success, with the highest survival rate (95%) recorded for plants from the 1.5 mg L^-1 mT treatment. Low mT concentrations enhanced shoot multiplication but limited root formation, affecting nursery survival. Results demonstrated that meta-Topolin induces a higher shoot number during lisianthus micropropagation, and at higher concentrations, it enables in vitro rooting of the shoots generated during the proliferation stage. This provides a practical alternative for large-scale commercial propagation of this ornamental species.