N Accumulation and Translocation in Four Japonica Rice Cultivars at Different N Rates

• Published in: Pedosphere Vol. 17; no. 6; pp. 792 - 800
• Main Authors: ZHANG, Yao-Hong, FAN, Jian-Bo, ZHANG, Ya-Li, WANG, Dong-Sheng, HUANG, Qi-Wei, SHEN, Qi-Rong
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.12.2007; College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095China
• Subjects: grain yield; Japonica rice cultivar; N accumulation; N application rate; N translocation; Oryza sativa; 堆积作用; 日本水稻; 降雨量; China, People's Rep; Japonica rice cultivar; N translocation; N accumulation; N application rate; grain yield
• ISSN: 1002-0160; 2210-5107
• DOI: 10.1016/s1002-0160(07)60095-2

Developing high-yielding rice （Oryza sativa L.） cultivars depends on having a better understanding of nitrogen （N） accumulation and translocation to the ear during the reproductive stage. Field experiments were carried out to evaluate the genetic variation for N accumulation and translocation in different Japonica rice cultivars at different N rates and to identify any relationship to grain yield in southeast China. Four Japonica cultivars with similar agronomic characteristics were grown at two experimental sites in 2004 with three N rates of 0, 60, and 180 kg N ha^-1. Dry weights and N contents of rice plants were measured at tillering, initiation, anthesis, and maturity. Grain yields exhibited significant differences （P 〈 0.05） among the cultivars and N application rates. Increasing N rates improved N uptake at anthesis and maturity in all four cultivars （P 〈 0.05）. N translocation from vegetative organs to the grains increased with enhanced N rates （P 〈 0.05）. N translocation to the grains ranged from 9 to 64 kg N ha^-1 and N-translocation efficiency from 33% to 68%. Grain yield was linear to N uptake at anthesis （r^2 = 0.78^＊＊） and N translocation （r^2 = 0.67^＊＊）. Thus, cultivars with a high N uptake at anthesis, low residual N in the straw at maturity, and appropriate low N fertilizer supply in southeast China should efficiently increase N-recovery rate while maintaining grain yield and soil fertility.