辽宁不同年代水稻品种生产力和氮肥效率对施氮水平的响应差异

阐明水稻品种演进过程中植株生产力和资源利用效率的变化特征，对高产高效协调的水稻品种选育和稻作技术改进具有重要的理论参考意义。本研究以1950-2010年间辽宁省的12个水稻主栽品种为材料，探讨氮肥施用对不同年代水稻品种植株生产力和氮肥利用效率的影响。结果表明，1990s及之后品种的最高生物学产量和籽粒产量均显著高于1980s及以前的品种，1990s及之后品种产量的递增主要归功于穗粒数的增加。其最高产量的施氮量显著高于1980s及以前的品种，低氮条件下不同年代品种间的生产力差异不显著。随年代的递进，水稻品种的氮肥农学利用率、偏生产力呈现递增趋势，但生理利用率和吸收利用率的变化趋势不明显；茎叶氮含量变化不明显，但籽粒氮含量呈下降趋势。随施氮量的递增，各年代品种植株含氮量均呈现递增趋势，但农学利用率、偏生产力、生理利用率、吸收利用率均呈下降趋势。在低氮条件下1990s及之后品种的氮肥利用效率与1980s及以前品种的差异不明显，但高氮下前者的氮肥利用效率显著高于后者。上述结果表明，虽然辽宁水稻植株生产力提升是品种改良和施肥水平提高的双重作用的结果，但在今后品种选育和栽培技术改进中要进一步协调好高产与资源高效的关系。

Responses of Plant Productivity and Nitrogen Use Efficiency to Nitrogen Fertilization Rate among Rice Varieties Released from Different Years in Liaoning Province

To study the changes of rice plant productivity and resource use efficiency during the variety improvement eras can benefit future genetic improvement and agronomic innovation for high-yield with high-efficiency. A field experiment was conducted at Shenyang, Liaoning Province, China, with 12 leading Japonica rice varieties released during 1950–2010 period under five nitrogen application rates. Our results showed that the highest biomass production and grain yield of the varieties released after 1990 were significantly higher than those of the ones released before 1989. The increases in grain number per panicle contributed to the main parts of historical improvement of rice yield. The amounts of N application for the highest yields of the varieties released after 1990 were significantly higher than those released before 1989, while there were no significant differences in plant productivity under the low N application rate among all the varieties. For all the N treatments, agronomic efficiency (AE) and partial factor productivity (PFP) increased with the years, however, there were no consistent trends of physiological efficiency (PE) and recovery efficiency (RE) among the years. Grain N concentrations decreased with the time, while no consistent trends were found in the changes of leaf and stem N concentrations. For all the varieties released in different years, plant N concentration increased and N use efficiencies (NUE: AE, PFP, PE and RE) decreased with increasing N application rate. The efficiencies of varieties released after 1990 were significantly greater than those released before 1989 at high N application rates, while there were no significant differences in NUE between varieties at low N application rate. These results demonstrate that genomic improvement and nitrogen application increasing have simultaneously contributed to the enhancement of rice productivity, though the progresses scales of rice productivity enhancement and NUE improvement are different. More efforts need to be paid in the new variety breeding and agronomic innovation for high-yield with high-efficiency in Liaoning Province.