Abstract

This study evaluated the response of four rain-fed lowland New Rice for Africa (NERICA) varieties (NERICA-L-12, NERICA-L-41, NERICA-L-42 and NERICA-L-56) and a popularly grown Oryza sativa (ITA 150) to nitrogen (0, 30, and 100 kg N ha^-1). The interactions between nitrogen and variety were not significant for all measured traits. Grain yields of the NERICAs were higher than the yield of ITA 150 (check) by 0.5 to 1.0 mg ha^-1. When pooled across N rates and years, yield differences among the NERICAs were not significant. Grain yield response to nitrogen was linear. At 100 kg N ha^-1, grain yield was significantly increased by 3.0 and 1.5 mg ha^-1 over the yields at 0 and 30 kg N ha^-1 respectively. Since grain yield response to N application was linear, further studies are recommended to determine the optimum rate of N for rain-fed lowland NERICA rice production.

Key words: NERICA rice, lowland rice, nitrogen fertilization.