Variations of Nitrogen Use Efficiency by Rice Genotype

Difference of N-use efficiency for rice varieties, correlation among rice grain yields and traits associated with N-use efficiency, difference of N-absorbed amount at different growth stages were analysed in N-fertilized and N-unfertilized conditions by using nine rice varieties. Results showed that total N-absorbed amount and physiological N-use efficiency at harvest-ing stage and N-translocation efficiency significantly differed among nine rice varieties in both N-fertilized and N-unfertilized conditions. N-use efficiency in N-unfertilized condition was higher than that in N-fertilized condition; Physiological N-use efficiency at harvesting stage was significantly correlated with total N-absorbed amount, N-translocation efficiency, rice grain yield, number of panicles, seed setting rate and harvest index. Total N-absorbed amount from booting stage to maturity stage were significantly different among rice varieties, while N-absorbed amount at early and middle growth stage weren't significantly different among rice varieties.