Erratic rainfall distribution pattern poses serious challenge to food production in the rainforest transitory zone of Nigeria. Low input technology through the adoption of drought tolerant varieties (NERICA) and the application of Arbuscular Mycorrhiza Fungi (AMF) inoculum could be an alternative option for double cropping of upland rice. Field trials were conducted in the Teaching and Research Farm of the Federal University of Agriculture, Abeokuta in the early and late cropping season of 2012 in the transitory rainforest agro-ecology of Nigeria. The objective was to investigate the performance of some selected upland NERICA rice to the application of AMF inoculum. A 6 x 2 factorial experiment was conducted; six upland rice varieties selected with and without the application of AMF, laid out in split plot arrangement, with AMF in the main block, while variety was in the sub-plot. Each treatment was replicated three times. In both seasons, significant (P - AMF. In the early season there was no significant (P > 0.05) varietal variability on grain yield/ha. Conversely, in late season NERICA 4 recorded significantly (P < 0.05) higher grain yield (1050kg/ha) as suggested in significantly (P < 0.05) higher panicle/m2 (59.50). Performance of NERICA 4 was significantly increased by application of AMF inoculation in the late cropping season.