Variation of Nitrogen Use Efficiency in Rice Genotypes

Abstract

This experiment was conducted to investigate the variation of nitrogen(N) uptake efficiency and their relationships withciency and partitioning parameters as physiological N use efficiency [PNUE], agronomic N use efficiency [ANUE], apparentrecovery [AR], partial factor productivity of aplied N [PFPn], N harvast index [NHI]. The N-efficient genotypes that producedhigh grain yield at both low and standard level of N were BG90-2, Ilpumbyeo(MNU)77-3-GH1-3-3-3-2-1-3-3, Ilpumbyeo, andSR19616-B-B-35-3-1. Inefficient genotypes that produced low yields at low N level but responded wel to N aplication wereyield was highly correlated with NHI and ANUE. The negative relationship implied a declining PNUE with increasing straw Ncontent. The grain yield-N efficiency parameters for individual genotypes indicated significant differences in slope and in the yieldobtained with soil N(GYo). Differences in GYo were due to genotypic variation in nitrogen efficiency parameters of use. NHI andANUE were related to nitrogen use efficiency. The work also indicates that genotypes with NHI and ANUE are likely to performwell in diferent fertility conditions.