The article uses the Average Treatment Effect (ATE) to estimate the population potential adoption rates of New Rice for Africa (NERICA) varieties in Nigeria when awareness of the new varieties and access to their seed are not constrained to farmers. It thus extends previous works in the literature which have focused on estimating potential adoption rates when only awareness of the technology is not a constraint to farmers. The adoption gaps due to lack of awareness and access to seed, and the determinants of adoption are estimated as well. Results show that NERICA adoption rate in Nigeria would have been up to 54% if the whole population were aware and up to 62% if they had access to NERICA variety seed. The actually observed 19% adoption rate implies a population adoption gap of 35% and 43% due to lack of awareness and access to NERICA seed respectively. It is also inferred from these results that when awareness is not a constraint, about 8% of the population will fail to adopt NERICA because of lack of access to its seed. Also famers with secondary education and farmers with access to extension services are more likely to adopt NERICA than farmers without.