Effect of toxic filtrates of Fusarium oxysporum f. sp. cubense on the development of banana (Musa cvs.) shoot tips

The objective of this study was to evaluate the effect of toxic filtrate of Fusarium oxysporum f.sp. cubense culture on the in vitro development of banana (Musa) shoot tips. Shoot tips from the varieties Nanicao (AAA -resistant to Panama disease) and Pisang mas (AA - susceptible to Panama disease) were isolated and cultivated in culture medium containing different concentrations of toxic filtrate of Fusarium culture. In the first assay, the concentrations of toxic filtrate tested were 0, 3, 6, 9 and 12.0% (v/v) and then, based on these results, a second assay was conducted using 0, 1.5, 3, 4.5 and 6% of Fusarium culture filtrate. Five replicates per treatments were used. Each replicate consisted of an erlenmeyer flask containing 15 ml of culture medium and five explants. The flasks were incubated on a shaker at 50 rpm and a daylength of 16 hours. After four weeks total fresh weight, fresh weight of shoots, and the length of shoots, were measured. No difference in the response of resistant and susceptible varieties was detected under low (0 - 3%) or high (> 6%) concentrations of Fusarium filtrate. At intermediate concentrations (3 - 4.5%) it was possible to discriminate between the resistant and susceptible varieties based on the measured parameters, primarily total fresh weight and fresh weight of shoots. These data suggest that the use of tissue culture and Fusarium culture filtrates may be used together to study hostpathogen interactions. (author). 21 refs, 1 fig., 2 tabs