Introduction. The use of mycorrhizal fungi as biofertilizers can reduce
chemical inputs during the nursery phase, allowing the production of high quality plant
material with reduced fertilizer inputs. The lack of complete knowledge of each crop’s
responsiveness to mycorrhizal symbiosis, however, is still a handicap to the routine
application of this biotechnology for commercial purposes. In our work, the influence of
early mycorrhization as an alternative to standard P fertilization programs for two
tropical crops, papaya and pineapple, was assessed in a greenhouse experiment.
Materials and methods. Papaya seedlings and pineapple planting material
were inoculated with the arbuscular mycorrhizal fungus (AMF) Glomus mosseae
and cultured on substrates with increasing amounts of soluble P. Data concerning
plant development and nutritional status were determined 5 months (papaya) and 7 months
(pineapple) after inoculation. Results. For both crops, benefits derived from
mycorrhization, expressed in terms of plant development and nutritional status, were
significantly higher than those derived from P application. Overall, mycorrhizal papaya
plants exhibited significantly higher biomass and macroelement contents in shoots than
plants without mycorrhizas at any P level. Mycorrhizal effects on pineapple at the lowest
P level were significant in terms of plant development and P shoot contents.
Conclusions. Differential benefits derived from mycorrhization seem to be
correlated to each crop’s internal P requirements. Our work highlights the potential
benefits of integrating early mycorrhization at the nursery stage in order to reduce P
fertilizer inputs in sustainable plant production systems.