Effect of Propagation Techniques on Growth, Development, Oil Yield, and Quality of Medicinal Cannabis (Cannabis sativa) Found in Lusikisiki, Eastern Cape, South Africa

This study investigated the influence of cutting techniques on the growth, development, yield, and oil quality of Cannabis sativa found in the Eastern Cape Province. The greenhouse pot experiment was conducted at Dohne Agricultural Development Institute (DADI), Stutterheim, Eastern Cape, during the winter and summer growing seasons of 2024/25. It was laid out in a Randomized Complete Design (RCD) with three treatments replicated three times. The treatments used were herbaceous shoot cutting with two different leaf area (LA) trimming amounts and sexual propagation. The parameters measured were plant height, number of branches, stem girth, number of weeks to first flowering, number of flowers, flower sex, number of weeks to 50% embar colorations, plant fresh weight, leaf and flower weights, and dry leaf and flower weights. The flower oil yield and cannabinoid composition were determined using GC-MS. The results indicate that the sexually propagated plants were taller (p < 0.05) with vigorous growth; had the highest fresh plant, leaf, and dry leaf weights; and had a higher number of male flowers overall. Herbaceous shoot cutting without LA trimming showed a significantly higher numbers of branches and flowers, as well as more rapid flowering, fresh and dry flower weights, and physiological maturity. The highest number of female flowers was recorded from cuttings, irrespective of the cutting technique. Additionally, cannabinoid concentrations in Cannabis sativa oil were influenced by the propagation techniques. In the first growing season, herbaceous shoot cutting with 50% LA trimming had the highest CBD, while in the second growing season, the sexually propagated treatment had the highest CBD concentration. Additionally, herbaceous shoot cutting without LA trimming recorded the highest Δ9-THC concentration, followed by the treatment with 50% LA trimming during the first growing season. These findings indicate that asexual propagation through cuttings is a suitable propagation choice for flower production for pharmaceutical purposes, as female-only plants can be selected. However, sexual propagation should be used for fibre production.