BANANA JUICE AS AN ALTERNATIVE ENERGY SOURCE FOR BANANA IN VITRO GROWTH MEDIUM

Energy sources in tissue culture media are important for plants whose photosynthetic efficiency is insufficient under in vitro conditions. However, the cost of tissue culture grade energy sources is high, thus making tissue culture derived plantlets expensive. The cost of table sugar commonly used in commercial tissue culture laboratories and a substitute for tissue culture grade sucrose in Uganda, is also relatively high given the volumes used. The aim of this study was to evaluate the possibility of exploiting banana (Musa spp.) juice, as an energy source in place of table sugar or tissue culture grade sucrose. Banana juice was extracted from the locally available East African Highland Banana (EAHB) beer cultivars, Mbidde-Kabula, Pisang awak (Kayinja) and Km 5, and used at levels of 20, 30, 40 and 50 ml l-1. The quality and amount of juice necessary to support in vitro growth of cooking EAHB cultivars Nakabululu, Nakitembe and Nakinyika was evaluated. The juice had varied composition of salts, sugars and organic acids; but with pH compared with table sugar solution. The highest number of shoots and shoot height was observed when bananas were cultured on media supplemented with 50 ml l-1 Kayinja juice. This response was greater than that observed with culture media supplemented with the control energy source of 30 g l-1 of table sugar. Results also showed that banana juice not only enhanced micropropagation but also improved in vitro plantlet vigour and reduced the cost of energy sources by 30%.