Comparative in vitro Regeneration Potential of Indian Bean Genotypes from Embryonic Axis Explant

Aim: To develop and evaluate an in vitro regeneration protocol from embryonic axis (EA) explants of Indian bean using four different genotypes (GP-1, GP-189, GNIB-21 and GNIB22). Study Design: The experiment was conducted using a completely randomised design (CRD) with five replications. Place and Study Duration: This study was conducted at the Plant Tissue Culture Laboratory, Main Sugarcane Research Station, Navsari Agricultural University, Navsari, during 2021–2023. Methodology: Excised embryonic axes from imbibed seeds of four Indian bean genotypes were cultured on Shoot Induction Medium (SIM) containing BAP (0.5 mg/L), kinetin (0.5 mg/L), and polyvinylpyrrolidone (1 mg/L) for five days. The shoot apical meristem and plumule were then decapitated to induce multiple shoots from the cot-node region. Decapitated EAs differentiated into multiple shoots from the cot-node region on SIM. Elongated shoots were transferred to Shoot Elongation Medium (SEM) containing GA₃, kinetin, and asparagine, followed by Root Induction Medium (RIM) containing IBA (0.7 mg/L) and polyvinylpyrrolidone (1 mg/L). Rooted plants were subsequently hardened and evaluated for survival and regeneration. Results: Significant differences among genotypes were observed for shoots per explant and shoot length. Two genotypes (GP-1 and GP-189) showed root induction from elongated shoots, with significant variation in roots per shoot and root length. Both genotypes exhibited 100% survival during hardening. The regeneration percentage ranged from 44.08% (GP 1) to 50.07% (GP 189). Conclusion: The study successfully demonstrated in vitro regeneration of fertile Indian bean plants from decapitated embryonic axis explants. The developed regeneration protocol can serve as a prerequisite for genetic transformation and genome-editing studies in Indian bean.