Abstract

Banana plants (Musa spp. L.) cv 'Great dwarf' were amended with free-living N₂ fixing bacteria (FLNFB) and arbuscular mycorrhizal fungi (AMF) and the presence of the burrowing nematode Radopholus similis was monitored in the field. Five treatments were applied by inoculating banana roots with four strains of FLNFB, that is C1, C2, C3 and C4 isolated from the rhizoplane of the same banana cultivar, or by keeping them uninoculated. The largest number of nematodes was found in the untreated roots and the lowest in the roots inoculated with C4. The largest percent of mycorrhizal colonization was found when banana roots were inoculated with C1 and the lowest in roots that were not inoculated. The number of R. similis decreased with increased colonization with AMF. The largest percentage of necrosis of the banana roots was found when banana roots were not inoculated and the lowest in roots that were inoculated with C4. The necrosis of the roots increased with increased number of R. similis, but decreased with increased colonization with AMF. It was found that inoculating the banana cv 'Great dwarf' with FLNFB increased the root colonization with AML, and reduced the number of nematodes and root damage.

Key words: Arbuscular mycorrhizal fungi, burrowing or banana-root nematode, free-living N₂ fixing bacteria, plant development.