The survival rate and development of micropropagated plantlets from different cassava clones have been improved by introducing AM fungi able to establish effective mycorrhizal symbiosis with the plant. The addition of NAA to the growing medium did not affect significantly shoot development nor the number of rooted explants for any of the clones tested. However, the number and length of the roots produced in vitro was influenced by the auxin, in the sense that more roots, although shorter, were induced in presence of the hormone. This differential rooting pattern did not have any important consequence for the further acclimatization of the SOM-1 and 05 clone plantlets. For clones 35 and 50 the differences in root development, as a consequence of NAA addition, led to a decreased (clone 35) or increased survival rate (clone 50) after the acclimatization phase. It is therefore difficult to reach a general conclusion about the effect of the auxin on the
acclimatization of the cassava plantlets.