Electronic Journal of Plant Breeding

The present investigation was carried out at the experimental farm of Rice Research and Training Center, Sakha, Kafer El-Sheikh, Egypt during 2008 and 2009 seasons to study the physio-morphological behaviour of some rice genotypes under low and high nitrogen application. Twenty one genotypes were tested under three different nitrogen levels viz, 0, 75 and 150 kg N/ha for ten traits viz, flag leaf area, chlorophyll content, days to heading, panicle weight, no. of filled grains/panicle, no. of panicles/plant, 1000-grain weight, grain yield t ha⁻¹, grain yield efficiency index (GYEI) and agronomic nitrogen use efficiency (ANUE). The genotypes were divided into three groups i.e., japonica/japonica (J/J), japonica/indica japonica (J/IJ) and indica japonica/indica japonica (IJ/IJ). GZ6296 x Giza178-1 and GZ6296 x Giza 178-3 gave the highest values of no. of filled grain/panicle and no. of panicles/hill under low input of nitrogen. Giza177/Sakha101 and Giza176/GZ6944 (J/J) gave the highest grain yield under low input of nitrogen followed by the genotypes derived from Giza178/GZ6296 (IJ/IJ).