Efficient and rapid in vitro micropropagation of MD2 and H4 pineapple varieties

Pineapple plays an important role in international trade and supports of more than a million households in Côte d’Ivoire. However, its yield is subject to pedoclimatic problems and erosion of genetic potential of plant material. This study aims to establish an effective in vitro yield protocol for MD2 and H4 pineapple varieties. Therefore, the effects of 6-benzylaminopurine (BAP) combined with different concentrations of 2-isopentenyladenine (2-iP), with variable light intensity and activated charcoal on leaf shoot proliferation and elongation were tested. Analysis of variance revealed that Murashige and Skoog medium (MSB5) supplemented with 2 mg/L BAP combined with 0.25 mg/L 2-iP recorded the highest average number of microshoots (13.50 microshoots) in MD2 variety, while 2 mg/L of BAP combined with 0.5 mg/L of 2-iP recorded the best average number of shoots (15.20 microshoots) in H4 variety. Maximum microshoot elongation (7.81 cm and 7.03 cm for MD2 and H4, respectively) was obtained with 2 mg/L BAP combined with 0.25 mg/L of 2-iP. Light intensity of 1500 lux produced 14.06 and 14.86 microshoots in MD2 and H4, respectively. In contrast, maximum microshoot elongation (4.40 cm and 4.13 cm in MD2 and H4, respectively) was recorded at 2000 lux light intensity. A 2 g/L of activated charcoal inhibited microshoot proliferation. However, it induced an elongation of 7.50 cm in MD2 and 7.07 cm in H4. Microshoots were rooted on MS medium supplemented with 100 mg/L myo-inositol, 30 g/L sucrose, 200 mg/L glutamine, 1 mg/L naphthalene acetic acid (NAA), 2 mg/L indole-3-butyric acid (IBA), 2 g/L activated charcoal, all solidified with 6g/L agar. In conclusion, the combination of 2 mg/L BAP and 2-iP (0.25 - 0.5 mg/L) is recommended for better in vitro shoot proliferation in MD2 and H4 varieties. Light intensities of 1500 - 2000 lux are ideal for better shoot proliferation and elongation. Finally, the addition of 2 g/L activated charcoal to the medium improves shoot elongation and rooting in MD2 and H4 varieties.