杂交水稻

为了明确不同施氮条件对超级杂交稻产量形成和氮肥利用的影响 ,2 0 0 1年在湖南长沙进行了氮肥试验。结果表明 ,施氮量的影响十分明显。在 0～ 2 40kg hm2 纯氮范围内 ,施氮量与产量呈单峰曲线 ,以 180kg hm2 的施氮处理的产量最高 (10 .7t hm2 ) ,在 12 0～ 180kg hm2 的施氮区间内增产效应最明显。氮肥处理之间产量差异的主要原因一是施氮量与每穗粒数呈极显著正相关 (r=0 .92 0 4 ) ,二是在低氮水平下 (0～ 12 0kg hm2 )施氮量对穗数有明显影响。超级杂交稻对抽穗期源器官有特殊的要求 ,施氮明显影响后期光合产物的积累。较高的施氮量 ,能保证超级杂交稻达到较高的叶面积指数 (LAI) ,在抽穗期维持较高的叶片干物质分配比例和单茎叶片重 ,有利于后期植株光合能力的提高 ,同时也有利于防止早衰 ,促进光合产物的完全彻底转运 ,发挥超级杂交稻的增产潜力。氮肥农学利用率 (AE)在施肥量之间的变幅较大 ,其中 180kg hm2 施氮量处理的最高 ,达 16.10 ,而 2 40kg hm2 施氮量处理的最低 ,仅为 7.43。

To clarify the effects of different nitrogen application treatments on grain yield construction of super hybrid rice and utilization efficiency of nitrogen fertilizer, the nitrogen fertilizing experiment was conducted with Liangyou Peijiu, the pioneer super hybrid rice combination, as the material at Changsha, Hunan in 2001. The results showed that the applied amount of nitrogen had a significant effect on grain yield. During 0～240 kg/hm 2 (pure nitrogen), the relation of N amount to grain yield was expressed in a single peak curve with the peak (10.7 t/hm 2) of grain yield at 180 kg/hm 2 of N and with the most apparent yield increasing effect between 120 and 180 kg/hm 2 of N. The important reasons for the yield difference among different N applications were that there existed a very significant positive correlation (r=0.920 4 ** ) between N amount and spikelets per panicle and a remarkable effect of N amount on effective panicles per hectare under low N amount (0～120 kg/hm 2). Super hybrid rice had a special requirement to the source organ at heading stage and applying N had an obvious effect on the accumulation of dry matter in late stage. A higher N amount would ensure a higher LAI of super hybrid rice and maintain a higher rate of leaf dry matter and blade weight per shoot at heading stage, which is favourable to increasing the photosynthetic capability of plants and keeping from early senescence and promoting the complete transfer of photosynthates in late stage to fully make use of the great yield potentiality in super hybrid rice. There existed a great variation in the agronomic efficiency (AE) of N fertilizer among various N treatments. The highest AE (16.10) occured at the N amount of 180 kg/hm 2 and lowest (7.43) at 240 kg/hm 2.