Testing for a Suitable Culture Medium for Micropropagation of East African Highland Bananas

A study was conducted to find a suitable culture medium for micropropagation of East African highland bananas ( Musa spp.). Modified Eriksson (ER), Gamborg's B-S (B-S) and Murashige-Skoog (MS) media were tested with a roasting cultivar Gonja-Horn plantain (AAB), a dessert Bogoya-Gros Michel (AAA) and three East African highland cooking (AAA) cultivars Kibuzi, Mbwazirume and Namwezi for in vitro proliferation induction. The media were supplemented with 4.5 mg l -1 Benzylaminopurine (BAP) and with or without 0.186 mg l -1 Naphtalene acetic acid (NAA). Only ER and MS gave proliferation. AAB cultivar proliferated significantly more than AAAs which did not differ among themselves. The AAA cultivars showed precocious rooting in the absence and presence of 0.186 mg l -1 NAA on ER and MS media supplemented with 4.5 mg l -1 BAP. However, the presence of auxin NAA significantly lowered shoot proliferation with concomitant significant induction of precocious rooting. This indicated a high level of endogenous auxin in these cultivars and, therefore, the unnecessity of exogenous auxin for their maximum in vitro proliferation. It was also found that ammonical nitrogen content determined the suitability of a culture medium thus making ER an alternative to the MS salts.