Influence of plant growth regulators, basal medium strength, and carbon sources on in vitro regeneration and genetic stability of Amomum subulatum Roxb.: a threatened cash crop from Northeast India
摘要
Large cardamom, an endangered spice crop from northeastern India, faces production challenges due to several factors, including climate change, pathogens, and soil degradation. While traditional rhizome propagation is slow and pathogen-prone, it necessitates the availability of an efficient alternative for healthy germplasm for mass cultivation. Therefore, in vitro micropropagation offers a sustainable solution for mass production of disease-free, high-yielding plants while preserving genetic diversity and restoring declining plantations. In this study, a complete regeneration protocol was optimized using rhizome explant via both direct and indirect organogenesis. The entire procedure, from explant inoculation to plant acclimatization, is completed within 50 to 60 d. While full-strength Murashige and Skoog (MS) medium supplemented with 1.0 mg L–1 BAP, 1.0 mg L–1 kinetin, and 0.4 mg L–1 NAA yielded maximum shoot multiplication via direct organogenesis, 1.0 mg L–1 IAA, 0.4 mg L–1 2,4-D, and 1.0 mg L–1 NAA yielded optimum callus induction, and 1.0 mg L–1 BAP, 0.3 mg L–1 kinetin, and 0.5 mg L–1 NAA yielded maximum shoot induction via indirect organogenesis. Maximum rooting was achieved using MS medium with 0.3 mg L–1 IBA, 1.0 mg L–1 IAA, and 1.0 mg L–1 NAA. Indirect organogenesis was successful with MS medium containing 2,4-D, NAA, IAA, and casein hydrolysate. Application of glucose or sucrose also showed differential impact on organogenesis. The assessment of genetic fidelity using ISSR and ScoT markers further validated the stability of the genome.