Plant Characteristics of High-Yielding Upland Rice Cultivars in West Africa

In West Africa, upland rice (Oryza spp.) is typically grown in low-input production systems under low soil fertility conditions. Genetic improvement may offer a cost-effective approach to improving the productivity rather than approaches that rely solely on external nutrient inputs. In the 1990s, the upland rice breeding program of the West Africa Rice Development Association (now Africa Rice Center [AfricaRice]) developed New Rice for Africa (NERICA) cultivars. However, recent studies suggest that there is scope for improving on the currently available NERICA cultivars. The objectives of this study are to (i) quantify yield advantage of two cultivars (Aus 257 and IR 74371-3-1-1) which were identified as high-yielding ones from a wide range of materials, over NERICA 1, and (ii) identify plant characteristics of these two high-yielding cultivars. Data were compiled from nine on-station and 23 on-farm trials in Benin. On average over all the trials, the two cultivars out yielded local check upland NERICA 1. Particularly, their relative yield advantage was higher when NERICA 1 showed low yield. Aus 257 had greater biomass accumulation, harvest index (HI), and uptake of N, P, and K. Greater biomass accumulation was the result of high leaf area index (LAI). Cultivar variation in nutrient-use efficiency also contributed to high yield, and IR 74371-3-1-1 showed higher nutrient-use efficiency than NERICA 1 and Aus 257. These results suggest that the use of the two cultivars with greater biomass accumulation, harvest index, nutrient uptake, and use efficiency is critical for improving rice yield.