Mycorrhizal formation with appropriate AM fungi increased significantly the development of the cassava clones. A similar AM effect on plant growth has been described for micropropagated plants of the tropical crop Annona cherimoZa Mill when inoculated with mycorrhizal fungi after the acclimatization phase (Azcon-Aguilar et al., 1994). Because typical arbuscules were formed, AM was probably functioning by its recognized role of improving nutrient acquisition by the host plant.
The effects of mycorrhizal inoculation on plant growth may also be due to improved rhizogenesis, as has been suggested for other crops (Schubert et al., 1990). Since AM fungi produce plant hormones (Barea and Azcon-Aguilar, 1982), they might improve root formation and development of the in vitro-produced cassava plantlets.