LAUSR

Ananas comosus var. MD2 is currently the most preferred pineapple variety in the international market due to its pleasant aroma and high Brix acidity ratio. In vitro approaches such as callus culture is promising in producing disease-free plantlet. However, there are limited studies reported on callus culture of MD2 variety despite the potential of in vitro regeneration through biotechnological advances. The purpose of the study was to determine the effect of plant growth regulators (PGRs) i.e., 2,4dichlorophenoxyacetic acid (2,4-D), 6-benzylaminopurine (BAP) and Thidiazuron (TDZ) on callus induction from leaf explant of MD2 pineapple. Leaf base explants were cultured on Murashige and Skoog (MS) media supplemented with varying concentration of 2,4-D (0.5 to 6.0 mg/L) alone and in combination with BAP (1.0 to 3.0 mg/L). The frequency of callus induction was seen significantly highest (91.67±8.33%) with maximum callus fresh weight (0.25±0.07 g) at a combination of 2.0 mg/L 2,4-D and 2.0 mg/L BAP. The shortest duration of callus formation was seen on day 12 with the lowest concentration of 2,4-D, 0.5 mg/L. There is a moderate correlation between the earliness of callus formation and the frequency of callus induction (P<0.01). The most favourable media for callus proliferation was 6.0 mg/L 2,4-D and 2.0 mg/L TDZ as the highest fresh weight of 1.52±0.03 g was recorded. Callus culture has the potential to be a source of plant material and secondary metabolites production. In this study, 2,4-D and BAP have successfully induced callus in MD2 pineapple.