不同基因型水稻氮利用效率的差异及评价

VARIATION OF NITROGEN USE EFFICIENCY OF RICE DIFFERENT IN GENOTYPE AND ITS EVALUATION

随着人们对农田氮肥过量施用导致肥料利用率下降和环境污染等问题认识的逐渐加深,不同基因型水稻氮营养效率的研究得到了普遍重视。采用177个粳稻基因型在两个施氮水平下进行田间筛选试验来评价水稻的产量、吸氮量和氮素生理利用效率的变异情况。结果表明,随着供氮水平的增加,水稻的产量和吸氮量随之增加,氮生理利用效率却随之降低;在相同的供氮水平下,不同水稻基因型之间的产量、吸氮量和氮生理利用效率存在显著差异。根据水稻在两个供氮水平下的产量水平把水稻分为四个类型:双高效型、低氮高效型、双低效型和高氮高效型。氮高效基因型可描述为在不同供氮水平下都有较高的产量,同时意味着氮高效品种能吸收大量的氮或有较高的氮生理利用效率。水稻成熟时较低的秸秆氮浓度可表明水稻具有较高的氮生理利用效率。

N use efficiency of rice is key to its overall yield potential, and efforts to improve the key potential must be guided by a thorough understanding of the process that governs N use efficiency. Field experiment was conducted to assess differences in grain yield, N accumulation, and N physiological use efficiency between 177 genotypes of rice japonica （71 semilate varieties （130 - 150 d） and 106 late varieties （151 - 172 d） under two levels of N supply （0 and 180 kg hm^-2） in 2003. Grain yield and N accumulation increased with the N rate, while physiological N use efficiency decreased. Significant differences in grain yield, N uptake and N physiological use efficiency were observed between genotypes within the same variety group under the same N application rate. Based on grain yield under two N rates, genotypes within each group were divided into four types, such as efficient-efficient, inefficient-efficient, inefficient-inefficient, and efficient-inefficient. High N use efficiency（NUE）cultivars produced high yields when N was applied, and low NUE cuhivars low yields. Thus genotypes which have promising traits for improved N uptake and N physiological use efficiency are identified. Those with higher N physiological use efficiency were lower in N concentration in straw at maturity. Further study, is needed to elucidate mechanisms involved in high N uptake and N physiological use efficiency.