In Vitro Bulb‑Scale Propagation of Lilium leichtlinii var. maximowiczii for Urban Landscaping

ABSTRACT: This study was conducted to establish an efficient in vitro mass-propagation system for the Korean native bulbous plant Lilium leichtlinii var. maximowiczii and to lay the foundation for supplying the produced bulbs for use in flowerbeds. Although this species is a promising native bulbous lily for urban flowerbeds, its use has been limited by the lack of an efficient system for large-scale propagation. L. leichtlinii var. maximowiczii is distributed in the northern part of Gyeonggi-do, Gangwon-do, and the eastern region of Gyeongsangbuk-do in South Korea, and is a native lily species with very high ornamental value. Among the tested disinfection protocols, a 0.1% (w/v) benomyl solution pretreatment for 1 h, followed by 70% (v/v) ethanol (EtOH) for 30 s and sequential surface sterilization in 1% (v/v) sodium hypochlorite (NaOCl) for 20 min and 2% (v/v) NaOCl for 10 min, was the most effective for in vitro introduction of bulb scales. As a result of bulblet induction using combinations of plant growth regulators, the medium containing 2.2 µM BAP + 5.7 µM IAA produced the highest number of bulblets (2.5 ± 0.12 per survived explant; total 38), followed by 4.4 µM BAP + 2.7 µM NAA (2.0 ± 0.00 per survived explant; total 24). Following a total culture period consisting of introduction (3 weeks), formation (3 weeks), and expansion (7 weeks), the regenerated plantlets were acclimatized for 1 week without mortality. These results revealed distinct roles for different plant growth regulators (PGRs) combinations in the regeneration process. The medium supplemented with BAP + IAA was optimal for initial bulblet induction, yielding the highest proliferation efficiency. The in vitro propagation technique established in this study is expected to provide a practical technical basis for the nursery production of uniform L. leichtlinii var. maximowiczii plantlets and to promote their wider use as native flowerbed plants.