https://doi.org/10.37229/fsa.fjh.2026.05.06

This study was conducted in the Plant Tissue Culture Laboratory, Department of Horticulture and Landscape Gardening, College of Agriculture and Forestry, University of Mosul, from July 15, 2024, to September 1, 2025. The research aimed to investigate the in vitro propagation of marjoram (Origanum majorana L.) through the initiation and multiplication of shoot tips obtained from field-grown plants. Explants were cultured on solid Murashige and Skoog (MS) medium supplemented with different concentrations of benzyladenine (BA: 0, 0.5, 1.0, 1.5, and 2.0 mg L⁻¹) and kinetin (Kin: 0, 2, 4, 6, and 8 mg L⁻¹) during the initiation stage for four weeks, followed by a multiplication stage for an additional four weeks on the same media. The results demonstrated that BA was more effective than Kin in promoting shoot proliferation. The highest number of shoots (8.8 shoots per explant) was achieved on MS medium supplemented with 2.0 mg L⁻¹ BA after eight weeks of culture. Subsequently, the regenerated shoots were transferred to half-strength MS medium containing different concentrations of indole-3-butyric acid (IBA: 0, 0.25, 0.5, 0.75, and 1.0 mg L⁻¹) to induce rooting. The best rooting response was obtained with 1.0 mg L⁻¹ IBA, which resulted in 100% rooting and an average of 11 roots per plant after six weeks. The rooted plantlets were successfully acclimatized and transferred to field conditions. These findings highlight the effectiveness of BA and IBA in enhancing in vitro propagation stages of marjoram, providing a reliable protocol for large-scale production of uniform and healthy plants for agricultural and research purposes.