Effect of indole-3-butyric acid on in vitro rooting and shoot development of potato ( <i>Solanum tuberosum L.)</i> under activated charcoal-supplemented conditions

Background Potato (Solanum tuberosum L.) is a major staple crop in Nepal, especially in the high hills and mountain regions. However, the national average productivity of 14.7 t/ha remains substantially below the global average of 21 t/ha, primarily due to limited access to disease-free seed and suboptimal tuber storage. Tissue culture offers an effective pathway for producing pathogen-free planting material. While general protocols exist, specific evidence regarding the optimal media composition and hormone levels for potatoes under Nepalese laboratory conditions remains limited.Methods A study was conducted to evaluate the effect of two concentrations of Indole-3-butyric acid (IBA) (0.5 mg/L and 1 mg/L) in Murashige and Skoog (MS) medium supplemented with 200 mg/L activated charcoal, specifically on the ‘Cardinal’ variety of potato.Results MS medium supplemented with 0.5 mg/L IBA and 200 mg/L activated charcoal produced significantly higher mean leaf number 22.73 ± 0.22 (mean difference vs. control: 16.06; 95% CI: 15.58–16.54), root number 1.48 ± 0.18 (mean difference: 0.69; 95% CI: 0.29–1.09), and node number 0.63 ± 0.16 at 23 days after subculture compared to 1.0 mg/L IBA and control treatments (p < 0.01). Additionally, the inclusion of activated charcoal have contributed to qualitative improvements in plantlet vigor by visually mitigating phenolic browning.Conclusion The combination of 0.5 mg/L IBA with 200 mg/L activated charcoal was identified as the optimal treatment for in vitro rooting and shoot development of ‘Cardinal’ variety under Nepalese laboratory conditions, providing a practical protocol for disease-free seed potato production.