Rhizogenesis of Cannabis sativa (L.) Stem Cuttings.
Cannabis sativa L.; rhizogenesis; stem cuttings.
The increasing demand for medicinal products derived from Cannabis sativa L. is driving the development of efficient and sustainable agronomic methods. Vegetative propagation by stem cuttings is essential to maintain the genetic uniformity of medicinal plants, and this study proposes to evaluate the use of Humic Acid (HA) and Naphthaleneacetic Acid (NAA) for root induction. The experiment will be conducted between May and June 2025 using 60 cuttings obtained from the middle and basal regions of mother plants cultivated by the ABRARIO Association (Cachoeiras de Macacu, RJ).. Experiments were conducted at the Association’s production site (Cachoeiras de Macacu, RJ, Brazil; 22°33'S, 42°50'W) using C. sativa cv. Painkiller XL. A factorial design (2 treatments × 6 concentrations) tested HA (0, 10, 20, 30, 40, 50 mmol C L⁻¹) and NAA (0, 500, 600, 700, 800, 900 mg L⁻¹), with five replicates (60 cuttings). Cuttings taken after the 7th node from median/basal regions underwent, immersion (HA: 72h; NAA: 10s), and rooting in a climate-controlled chamber (25.9°C, 89.6% RH, 115 μmol m⁻² s⁻¹ PPFD) using Carolina Soil® substrate. After 14 days, roots were digitized (WinRHIZO Pro 2022) to quantify root number, length, surface area, and volume. Non-parametric analyses (Kruskal-Wallis/Dunn’s test, α* = 0.00076) showed HA at 30–50 mmol C L⁻¹ matched NAA at 800 mg L⁻¹ in root number, length, and surface area (p > 0.05), outperforming controls by 35–86% (p < 0.05). However, NAA 800 mg L⁻¹ yielded 34–42% greater root volume than optimal HA treatments (p = 0.010–0.032). Results confirm HA (30–50 mmol C L⁻¹) as a viable organic substitute for synthetic auxins in C. sativa propagation, addressing regulatory barriers while ensuring clonal uniformity.