Optimizing Plant Growth Regulator Combinations for Rapid in vitro Shoot Multiplication of Banana (Musa spp.)

Abstract

Banana (Musa spp.) is one of the most important fruit crops worldwide because of its nutritional, economic, and commercial value. However, production is adversely affected by several biotic and abiotic constraints, necessitating efficient in vitro propagation techniques for the rapid multiplication of disease-free planting material. This study evaluated the effects of different combinations of cytokinins and auxins on the in vitro shoot multiplication of banana using Murashige and Skoog (MS) medium. Kinetin and 6-benzylaminopurine (BAP), each at 4.0 mg L⁻¹, were combined separately with indole-3-acetic acid (IAA), indole-3-butyric acid (IBA), and α-naphthaleneacetic acid (NAA), each at 1.0 mg L⁻¹. Among the kinetin-based treatments, MS medium supplemented with kinetin + IBA produced the highest shoot proliferation (2.73 ± 0.25 shoots per explant), shoot length (1.81 ± 0.13 cm), and number of leaves (2.31 ± 0.16). Among the BAP-based treatments, MS medium supplemented with BAP + IAA recorded the highest shoot proliferation (2.96 ± 0.20 shoots per explant), shoot length (2.22 ± 0.81 cm), and number of leaves (2.58 ± 0.10). The results indicate that MS medium containing 4.0 mg L⁻¹ BAP + 1.0 mg L⁻¹ IAA or 4.0 mg L⁻¹ kinetin + 1.0 mg L⁻¹ IBA is effective for the in vitro shoot multiplication of banana. These optimised protocols provide a practical approach for rapid micropropagation and the large-scale production of healthy, disease-free banana planting material.