Abstract

Potassium nutrition has been used in controlling fungal and bacterial diseases of plants. However, this has not yet been tested on control of Fusarium (Fusarium oxysporum f.sp. cubense -Foc), a major fungal disease constraining apple banana production. This study was set up with a general objective to investigate the effects of potassium on tolerance to Fusarium wilt in apple bananas using chlorophyll content, stomatal conductance and severity of Fusarium wilt symptoms as indicators. A screen house pot experiment was set up using tissue culture plantlets of apple bananas cv Ndiizi. Treatments comprised of different sources of potassium (Manure, inorganic K and potassium solubilizing bacteria -KSB) in a full factorial combination. Manure and Muriate of potash (MOP) were applied at rates equivalent to 150 kg K/ha and KSB (Frateuria auranta) at a rate of 1 l/ha. Fusarium wilt was inoculated in half the pots at 8 weeks after planting. Measurements on chlorophyll content and stomatal conductance as well as growth parameters were taken on weekly basis from the time of inoculation. Fusarium wilt significantly reduced stomatal conductance and chlorophyll content of the plants. Application of integrated potassium management (KSB x MOP x Manure) significantly reduced Fusarium wilt symptom expression.

Key words: Chlorophyll content, stomatal conductance, Fusarium oxysporum sp. Cubense, manure, potassium.