Phosphorus response of Oryza sativa, O. glaberrima, and hybrid rice cultivars on an ultisol

Phosphorus (P) deficiency is a major constraint to upland rice production on Ultisols in the humid zone of West Africa. Integrated use of P-efficient cultivars and P nutrition is needed for enhanced sustainable productivity on these soils. This article reports on the P responsiveness of interspecific rice hybrids (crosses from Oryza sativa and O. glaberrima) along with O. sativa and O. glaberrima cultivars grown on an acidic Ultisol, low in available P. The cultivars differed in yield and P-uptake response to fresh and residual P. Two interspecific cultivars gave a linear response to P and produced the greatest grain yield under direct and residual P. The O. glaberrima cultivar CG 14 did not respond to the applied P, whereas the O. sativa cultivar was moderate in its performance. Our results show that the interspecific rice cultivars have the potential to adapt and perform well on acidic upland soil