Regulation of Callus Induction Efficiency in Banana Using Dichlorophenoxyacetic Acid in combination with Benzylaminopurine

Abstract

The regulation of callus induction in banana (Musa spp.) was investigated using plant growth regulators, specifically 2,4 dichlorophenoxyacetic acid (2,4 D) combined with other growth regulators to enhance callus formation efficiency. Different concentrations of 2,4 D, indole 3 acetic acid (IAA), and benzylaminopurine (BAP) were added to Murashige and Skoog (MS) basal medium to evaluate their effects on callus induction frequency, initiation time, proliferation efficiency and the number of regenerated calli. Results demonstrated that callus induction was significantly modulated by hormone concentrations with the highest frequency observed at specific concentration of MS medium containing 4.0 mg/L 2,4 D, 0.5 mg/L IAA, and 0.5 mg/L BAP, yielding 95% induction frequency of robust, creamy white callus within two to three weeks of explant inoculation. The efficiency of callus proliferation measured as the percentage of explants producing calli, peaked at 87.5% on MS medium with 1.0 mg/L 2,4 D. This concentration also yielded the highest number of regenerated calli (16 ± 0.22), followed by treatments containing 2.0 mg/L and 3.0 mg/L 2,4 D, which produced 15 ± 0.21 and 12 ± 0.16 calli per explant, respectively. In contrast, the lowest regeneration rate (7 ± 0.11) was observed with 7.0 mg/L 2,4 D. These results underscore the importance of selecting precise hormone concentrations to achieve optimal callus induction and proliferation. Overall, this study reveals that 2,4 D, combined with low levels of IAA and BAP, effectively induces callus in banana tissue culture, with an optimal concentration range for balancing induction frequency, initiation time and proliferation. These findings offer insights for enhancing callus culture protocols for bananas, providing a foundation for future research on somatic embryogenesis and regeneration in climate resilient banana cultivars