Rice yields have stagnated in West Africa at 1 to 2 Mg ha"^ because of unfavorable rice environments and poor management practices. Interspecific rice cultivars, the New Rice for Africa (NERICA), were developed by crossing Asian rice {Oryza sativa L.) and African rice (O. glaberrima Steud.) to improve upland and lowland rice productivity in resource-poor farmers' fields. This paper provides an overview of recent studies, performed by the Africa Rice Center and its partners, on evaluation of growth and yield performance of upland and lowland NERICA cultivars and modern Asian rice cultivars including the improved upland indica cultivars often termed aerobic rice. Upland NERICA cultivars were found to lack the expected combination of superior yield potential with weed suppressive ability (WSA) and adaptation to low soil fertility, instead sharing similarity in these characteristics with their O. sativa parent WAB56-104 but remaining inferior to their O. glaberrima parent CG 14 in terms of tillering ability and WSA. Some aerobic rice cultivars were identified for high yielding ability, strong WSA, and superior adaptation to low-fertility uplands and waterlimited lowlands. Some lowland NERICA cultivars outyielded improved lowland O. sativa checks and aerobic rice cultivars in favorable lowlands, whereas they did not perform well in water-limited lowlands. The implications of these findings for future challenges for genetic improvement in West Africa are discussed.
NERICA (New Rice for Africa) cultivars were crossed with Oryza sativa L. and O. glaberrima Steud. All the F 1 hybrids between NERICA and two strains of O. glaberrima were highly sterile, while the F 1 hybrids of NERICA with two cultivars of O. sativa showed differing levels of fertility depending on the cross combinations. NERICA cultivars were classified into three groups: (1) those compatible with both ssp. indica and ssp. japonica of O. sativa (i.e. NERICA12, NERICA15, NERICA16, NERICA17 and NERICA18); (2) those compatible with japonica but incompatible with indica (NERICA3, NERICA4, NERICA7, NERICA8, NERICA9, NERICA11, NERICA13 and NERICA14); and (3) incompatible with both types (NERICA1). In the first group of NERICA cultivars, four cultivars from NERICA15 to NERICA18 are derived from the same cross of CG 14/3*WAB 181-18, and they have the cytoplasm of CG 14, from an O. glaberrima strain. No 'bridging cultivar' between both cultigens was found in NERICA cultivars, but some NERICA cultivars were compatible with both japonica and indica. This finding is very useful for improvement of NERICA cultivars through hybridization.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.