Combination of NAA and BAP significantly enhances plantlet regeneration of Saccharum officinarum L. cv. PSJK 922

This study aimed to optimize callus induction and plantlet regeneration protocols for the commercial sugarcane cultivar PSJK 922. Callus induction from spindle leaf roll segments was performed using Murashige and Skoog (MS) medium supplemented with 2,4-D at concentrations of 0, 1, 2, 3 and 4 mg/L. Data were recorded on Callus Induction Frequency (CIF) and Callus Fresh Weight (CFW). The best callus with a friable texture and creamy white colour, was subcultured and transferred to regeneration media containing 25 combinations of NAA and BAP, ranging from 0 to 2 mg/L. Plantlet regeneration was evaluated over 14 weeks under controlled conditions. The parameters included plantlet regeneration, number of shoots, number of roots, shoot length, root length and Plantlet Vigour Index (PVI). The results showed that 2,4-D at concentrations of 3 and 4 mg/L were most effective for generating morphogenic callus with high CIF (83.33 %) and CFW (0.3834-0.4541 g). The statistical analysis revealed a significant effect of NAA and BAP combinations on plantlet regeneration (77.33 %, p < 0.047) observed from callus induced with 3 mg/L. In particular, the optimal regeneration medium was found to be 0.5 mg/L NAA and 1.5 mg/L BAP, when using callus induced by 3 mg/L 2,4-D, leading to higher shoot elongation (4.74 cm ± 0.32) compared to most other treatments. The combination exhibited the highest PVI (around 456), which indicates healthy plantlet development and overall quality. Thus, these findings can help optimize tissue culture protocols for elite sugarcane as well as large-scale propagation for accelerating germplasm multiplication and serving as a foundation for genetic transformation of elite lines.