Effect of benzylaminopurine on in vivo multiplication of French plantain (Musa spp. AAB) cv. ‘Itoke sege’

Journal of Applied Biosciences, 2014; 74:6086– 6090Objective: In vivo macropropagation is an alternative simple and cheap technique for banana multiplication. However, the response of cv. “Itoke Sege” to in vivo macropropagation combined with different benzylaminopurine (BAP) concentrations is not known. This study was conducted to determine the appropriate concentration of BAP for enhancing in vivo macropropagation of French plantain cv. ‘Itoke Sege’. Methodology and results: Sword suckers of about 70 - 80 cm tall and 14 -16 cm collar diameter were obtained from farmers’ fields in Rungwe district in Mbeya, Tanzania. Moistened sawdust was steamsterilized for 45 minutes and then filled for cooling in wooden propagators of 1.5 m x 2.20 m x 0.3 m dimension. Suckers were partially peeled, washed to remove roots and surface-sterilized for 15 seconds by dipping them in hot boiling water. The sterilized corms were desheathed to expose axillary buds and decorticated to suppress the apical meristems. Fifteen corms in three replications were each dipped in BAP at 0.0, 1.5, 3.0 and 6.0 mg/l for 12 hours and then planted into sawdust media. Irrigation was done immediately but subsequent watering was carried out when necessary. In vivo multiplication response was evaluated based on number of days to first shoot emergence, number of shoots per corm, number of roots per shoot and shoot size. Results showed that BAP concentration at 1.5 mg L-1 significantly (P < 0.05) reduced the number of days to first shoot emergence of 15.78 days followed by BAP at 3.0, 6.0 and 0.0 mg L-1 with 25.18, 28.39 and 36.43 days, respectively. Similarly, BAP concentration at 1.5 mg L-1 significantly (P < 0.05) increased sucker productivity with 17.11 suckers per corm followed by BAP at 0.0, 3.0 and 6.0 mg L-1 with 15.23, 13.08 and 12.96 suckers per corm, respectively. Corms treated with BAP at 1.5, 3.0, 6.0 mg L-1 significantly (P > 0.05) produced taller shoots with length of 27.0, 27.3 and 26.7 cm followed by corms treated with BAP at 0.0 mg L-1 with shoot length of 22.7 cm. Conversely, corms treated with BAP at 0.0 and 6.0 mg L-1 produced suckers with larger collar diameter of 3.4 and 2.4 cm followed by suckers from corms treated with BAP at 3.0 and 1.5 mg L-1 with collar diameters of 2.2 and 2.0 cm, respectively. Suckers from corms treated with BAP at 0.0 and 3.0 mg L-1 had larger number of leaves of 4.8 and 4.6 per sucker followed by suckers from corms treated with BAP at 1.5 and 6.0 mg L-1 with 4.0 and 3.8 leaves per sucker, respectively. Conclusion and application: Based on these findings, it is concluded that in vivo macropropagation combined with BAP at 1.5 mg L-1 is a suitable technique for improving multiplication and sucker growth of French plantain cv. ‘Itoke Sege’. The findings of this study provide an opportunity for the use of in vivo macropropagation coupled with BAP at 1.5 mg L-1 as an alternative simple and cheap technology for rapid and mass production of planting materials for recalcitrant plantain varieties. Further study is recommended to evaluate the response of cv. “Itoke Sege” to in vivo macropropagation combined with other cytokinebased growth regulators. Research is also required to test the responses of other recalcitrant plantain cultivars to in vivo macropropagation in combination with different BAP concentrations