Effect of thidiazuron on in vivo shoot proliferation of popular banana (Musa spp. L) cultivars in Tanzania

Journal of Applied Biosciences, 2018; 81:7214 – 7220Objective: Thidiazuron (TDZ) is a diphenyl urea-based cytokinin, which is non-degradable and persistent in plant tissues. The effect of these TDZ properties on in vivo banana proliferation when deshealthed corms are temporarily dipped in such growth regulator is unknown. The objective of this study was to evaluate the effect of temporary treatments with TDZ of deshealthed banana corms on in vivo sucker multiplication. Methodology and Results: The study was comprised of a split plot experiment in a randomized complete design with three replications each replication with 15 corms. The main plot factor was banana cultivars (Mtwike, Mzuzu and Bukoba) while the sub-plot factor was TDZ concentrations (0.5, 1.0, 2.0 and 3.0 mg/l). Moistened sawdust was steam-sterilized for 45 minutes and then filled for cooling in wooden propagators. Banana suckers were cleaned to remove roots and surface-sterilized for 15 seconds. The sterilized corms were deshealthed to expose axillary buds and decorticated to suppress the apical meristems. These corns were each dipped in TDZ at 0.5, 1.0, 2.0 and 3.0 mg/l for 12 hours and then planted into the sterilized sawdust media in the propagators. Results showed that the number of shoots per corm significantly (P < 0.05) increased as TDZ concentration increased from 0.0 to 2.0 mg/l but decreased as TDZ increased to 3.0 mg/l. The number of leaves per sucker significantly (P < 0.05) decreased as TDZ concentration increased from 0.0 to 3.0 mg/l. Conversely, corms treated with TDZ at 2.0 mg/l produced suckers with the largest number of leaves of 4.9 per sucker followed by corms treated with TDZ at 1.0, 3.0 and 0.5 mg/l with 4.5, 4.3 and 3.3 leaves per sucker, respectively. Banana cultivars had a significant (P < 0.05) effect on the number of shoots per corm where banana cv. Bukoba produced the largest number of shoots of 6.4 per corm while banana cv. Mtwike and Mzuzu produced 2.3 and 2.9 shoots per corm, respectively. Conclusion and Application: The findings from this study provide evidence that in vivo shoot multiplication rates and sucker growth of banana cv. Mzuzu, Bukoba and Mtwike can be increased by dipping for 12 hours deshealthed corms in TDZ solution at 2.0 mg/l. The low in vivo multiplication rates of banana cv. Mtwike and Mzuzu underscore the need for further studies to determine alternative best cytokine-based growth regulators