A first attempt to use a Fusarium subglutinans culture filtrate for the selection of pineapple cultivars resistant to fusariose disease

Pineapple, Ananas comosus L. Merr., cultivars differing in resistance to fusariose were examined for the phytotoxic effect of culture filtrate (CF), and fusaric acid (FA) isolated from Fusarium subglutinans (Wollew & Reinking) Nelson, Toussoun & Marasas. The possibility of using these substances on F, hybrids as selection agents for resistance was also evaluated. The phytotoxic effect of these substances was assessed in pineapple plantlets from tissue culture by placing them on wounded leaf segments. The resistance level of the F, hybrids and cultivars under natural conditions was measured in greenhouse field tests. The susceptible cultivars proved to be the most sensitive in each test, whereas resistant cultivars showed resistance to CF. FA affected all the cultivars independently of the degree of resistance of the cultivars The presence of other metabolites in CF was responsible for the screening effect between the varieties. Using CF as selection criteria allowed the selection of resistant plants with behaviour quite similar to plants where the fungus itself was used as the selection agent.