Iranian Medicinal Plants Society Journal of Medicinal plants and By-products 2322-1399 15 3 2026 05 01 Effect of Plant Growth Regulators and Explant Type on Direct Regeneration and Root Induction of Zarrin-Giah (Dracocephalum kotschyi Boiss) as a Medicinal Plant 311 320 135410 10.22034/jmpb.2026.370541.2042 EN Leyla Jalili Department of Plant Production and Genetics, Faculty of Sciences and Agricultural Engineering, Campus of Agriculture and Natural Resources, Razi University, Kermanshah, Iran Zeinab Chaghakaboodi Department of Plant Production and Genetics, Faculty of Sciences and Agricultural Engineering, Campus of Agriculture and Natural Resources, Razi University, Kermanshah, Iran Alireza Zebarjadi Department of Plant Production and Genetics, Faculty of Sciences and Agricultural Engineering, Campus of Agriculture and Natural Resources, Razi University, Kermanshah, Iran Research Institute of Medicinal Plants, Razi University, Kermanshah, Iran Leila Zarei Department of Plant Production and Genetics, Faculty of Sciences and Agricultural Engineering, Campus of Agriculture and Natural Resources, Razi University, Kermanshah, Iran Journal Article 2025 08 29 <em>Dracocephalum kotschyi</em> Boiss. (Lamiaceae), known in Persian as “Zarrin-giah” or “Denaei Lemon Balm”, is a medicinal plant native to Iran. It is used in traditional remedies and as a flavoring in tea and doogh (a yogurt-based drink). Extracts of this species contain bioactive compounds with reported therapeutic properties. Efficient micropropagation protocols can support its conservation and large-scale production. This study evaluated plant growth regulator combinations and explant types for direct regeneration and rooting of <em>D. kotschyi</em>. A completely randomized experiment with three replications was conducted in 2025 to investigate the effects of cytokinin (BAP), auxin (NAA), and explant type (leaf, hypocotyl, and cotyledon) on regeneration, as well as the effects of Indole-3-butyric acid (IBA) and culture media (MS and ½ MS) on rooting. Measured traits included regeneration percentage, number of shoots per explant, shoot length, number of leaves per shoot, rooting percentage, number of roots, and root length. Results showed that the combination of 1 mg/L BAP and 1.5 mg/L NAA applied to hypocotyl explants produced the highest regeneration percentage and improved shoot quality. In the rooting stage, the interaction between medium type and IBA concentration significantly influenced root formation. The best rooting response, including 100% rooting, occurred in ½ MS medium supplemented with 1–2 mg/L IBA. These results provide a practical protocol for efficient in vitro regeneration and rooting of <em>D. kotschyi</em> and support its micropropagation for medicinal use and conservation. https://jmpb.areeo.ac.ir/article_135410_26a10518701134ef6cd2797d79e43f67.pdf