This study investigated the effect of 2,4-dichlorophenoxyacetic acid (2, 4-D) and naphthalene-1-acetic acid (NAA) concentrations on callus induction and shoot regeneration in three sugarcane varieties: CO945, CO421, and N14. Young leaf spindle explants were cultured on Murashige and Skoog (MS) basal medium supplemented with 2, 4-D (0.0, 2.0, 2.5, 3.0, 3.5 and 4.0 mg L-1) and NAA (0.0 and 1.0 mg L-1). Experiments were laid out in completely randomized design replicated three times. Observations were recorded on percent of callus formation, percent of shoot formation and morphological characterization of callus. Data was subjected to analysis of variance (ANOVA) at 5%. Significantly higher callus production (93%) was observed at 3 mg L-1 2, 4-D. The presence of NAA tends to depress callusing and shoot production in sugarcane variety N14. The interaction between NAA and 2, 4-D had no significance on the parameters. Application of 2, 4-D between 2.0 and 3.5 mg L-1 gave the highest percent of callus formation and shoot formation in all sugarcane varieties. Application of 2.5 and 3.5 mg L-1 2, 4-D was the most effective for sugarcane callogenesis and regeneration for the three sugarcane varieties. NAA treatment in callus formation media is not beneficial.

Keywords: Sugarcane genotypes, 2, 4-D, NAA, callogenesis, regeneration