Grain yield and nitrogen use efficiency response to polymer coated urea for two indica-japonica hybrid rice varieties

Abstract

To meet the food demand of an increasing population, hybrid rice varieties with high yields were selected, including indica-japonica hybrids. However, information about growth characteristics under the utilization of coated urea was limited. In this study, growth performance and yield of two indica-japonica hybrid varieties under five coated urea rates (0, 150, 225, 300 and 375 kg N ha−1) were investigated, while two conventional late japonica were used as controls. Consequently, yield of indica-japonica hybrids was obviously higher than that of late japonica under a single application of coated urea, due to larger grain number per panicle. The relationship of yield and N rate was an open downward conic curve, while polymer coated urea for the maximum yield of the four varieties was about 225 kg N ha−1. The dry matter accumulation of indica-japonica hybrids was significantly higher than that of the late japonica. Nitrogen use efficiencies were higher under lower nitrogen rate.