Allelopathic effect of root exudates of cucumber cultivars on Fusarium oxysporum

In laboratory bioassays, the effects of root exudates of six cucumber cultivars (with different resistance to Fusarium wilt) were evaluated on spore germination, mycelial growth and mycelial biomass of Fusarium oxysporum. Root exudates of resistant cultivars significantly inhibited all these parameters, while, those of susceptible cultivars stimulated the spore germination and fungal growth. Root exudates of intermediate resistant cultivars neither affected the spore germination nor fungal growth. Our results suggest that the allelopathic effect of root exudates contribute to the resistance of cucumber cultivars to Fusarium wilt.