中文摘要：

在低氮（20mg／kg）、中氮（40mg／kg）和高氮（60mg／kg）水平下，测定和比较了不同类型稻种资源苗期氮素利用效率（NUE）的差异。结果表明：随着氮素水平的升高。不同生态型稻种资源苗期NUE呈下降趋势。不同类型稻种资源苗期NUE存在显著或极显著差异，且因氮素水平而异：低氮条件下，陆稻NUE显著高于水稻；中氮和高氮条件下，水、陆稻的NUE未达显著差异；低、中和高氮条件下。古老地方品种NUE显著或极显著高于现代育成品种，杂交组合NUE显著或极显著高于常规品种；低氮条件下，籼、粳稻NUE无显著差异；中、高氮条件下的籼稻NUE极显著低于粳稻。

英文摘要：

Nitrogen utilization efficiency （NUE） in rice germplasms with different ecological types were determined and analyzed during seedling stage under low nitrogen rate （20 mg/kgN）, medium nitrogen rate （40 mg/kg N） and high nitrogen rate （60 mg/kg N）. The results showed that NUE in different ecological rice germplasms reduced with increasing nitrogen rate and had significant or greatly significant differences with different nitrogen rates. NUE in upland rice was significantly higher than that in paddy rice under low nitrogen rate, whereas NUE between upland rice and paddy rice was not significantly different under medium and high nitrogen rates. NUE in contemporary breeding variety was significantly or greatly significantly smaller than that in ancient local variety under different nitrogen rate. NUE in hybrid combination was significantly or greatly significantly higher than that in conventional variety under different nitrogen rate. NUE in Indica rice was greatly significantly smaller than that of Japonica rice under medium and high nitrogen rates, but NUE between Indica rice and Japonica rice was not significantly different.