Determination of Optimal Hormone and Mineral Salts Levels in Tissue Culture Media for Callus Induction and Growth of Industrial Hemp (Cannabis sativa L.)

Historically, industrial hemp (Cannabis sativa L.) has been a valuable source of metabolites and compounds, such as cannabidiols. There is a need for large amounts of plant tissue to be grown under controlled environments, and plant tissue cultureis one unique way to yield this tissue. The purposes of this study were to determine: 1) the optimal concentrations (μM)/ratios of auxin:cytokinin in media and; 2) the optimal mineral salts formulation for callusinduction and callusgrowth in select hemp cultivars. To find the optimal concentration/ratios, 16 different combinations of auxin:cytokinin and three different mineral salts formulations were evaluated. The three mineral salts formulations tested were MS salts, MB5D1K and an MTSU formulation. The top performing hormone formulations were determined to be equal concentrations (1:1, 2:2, 3:3 μM) of auxin and cytokinin. The top performing media hormone formulations for callusinduction were determined to be 2:1, 2:2, 2:3, and 3:2 μM (auxin:cytokinin). The optimal mineral salts formulation was determined to be MD5D1K. Therefore, the overall optimal media formulation for hemp callusproduction would be MB5D1K salts with the concentration/ratioof 2:2 μM (auxin:cytokinin).