Abstract

Efficient micropropagation is essential for the large-scale clonal propagation of elite Cannabis sativa cultivars. However, the development of broadly applicable in vitro protocols remains challenging because morphogenic responses vary considerably among genotypes. This study evaluated the in vitro micropropagation of two cultivars, Northern Light and Mimosa, with the aim of identifying genotype-dependent differences throughout the propagation process and optimizing culture conditions. Nodal segments and in vitro-derived seedlings were established on half-strength Murashige and Skoog (MS) medium. Shoot proliferation was evaluated using different concentrations of 6-Benzylaminopurine (BAP), while root induction was assessed with Indole-3-Butyric Acid (IBA) and α-Naphthaleneacetic Acid (NAA). Rooted plantlets were subsequently acclimatized under controlled greenhouse conditions.

Both cultivars were successfully established through direct organogenesis without callus formation. Low BAP concentration (0.1mgL⁻¹) promoted efficient shoot proliferation, whereas higher cytokinin levels induced severe hyperhydricity. The greatest genotype-dependent differences were observed during root induction. Northern Light exhibited a maximum rooting rate of 42% after approximately 30 days on medium supplemented with 0.2mL⁻¹ IBA, whereas Mimosa reached approximately 90% rooting within 7-20 days under the same conditions. These contrasting rooting responses were reflected in acclimatization success, with survival rates of 75% and 92% for Northern Light and Mimosa, respectively. Our findings demonstrate that genotype is the primary factor determining micropropagation efficiency in Cannabis sativa, with rooting representing the principal bottleneck limiting propagation success. These results highlight the need for genotype-specific optimization rather than universal protocols and provide a practical framework for the commercial clonal propagation of elite Cannabis cultivars.

Keywords: Clonal propagation; Direct organogenesis; Rhizogenesis; Medicinal cannabis