不同施氮条件下杂交中籼稻的群体质量与产量形成

Population quality and grain yield construction of mid-season indica hybrid rice "Wandao153" under different N applications

以超高产中籼杂交水稻“皖稻153”为材料,在大田条件下,比较了不同施氮量对杂交中籼水稻群体质量、氮肥利用和产量形成的影响。结果表明,150 kg（N）·hm^-2、187.5 kg（N）·hm^-2、225.0 kg（N）·hm^-2、262.5 kg（N）·hm^-2和300.0 kg（N）·hm^-2等5种施氮量下杂交中籼稻产量差异显著,在150-262.5 kg（N）·hm^-2范围内,产量随施氮量增加而增加,以262.5 kg·hm^-2施氮处理的产量最高（11 355 kg·hm^-2）,施氮量增加到300.0 kg（N）·hm^-2产量下降。不同施氮处理间产量差异主要是因为群体颖花量的差异,施氮量与群体颖花量呈极显著正相关（r=0.963 5^＊＊）。施氮量明显影响群体质量,适宜施氮量（262.5 kg·hm^-2）能保证杂交中籼水稻达到较高的叶面积指数（LAI）和粒叶比,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和光合产物的积累,使后期物质积累的贡献率提高,从而增加产量。适宜施氮量（262.5 kg·hm^-2）的氮肥农学利用率也最高。推荐江淮稻区杂交中籼稻超高产栽培的适宜施氮量为262.5 kg·hm^-2。

The effects of nitrogen application on the population quality,grain yield construction and utilization efficiency of nitrogen fertilizer in mid-season indica hybrid rice ＂Wandao153＂ were investigated under field conditions.Five nitrogen treatments were set at 0 kg（N）·hm^-2,150.0 kg（N）·hm^-2,187.5 kg（N）·hm^-2,225.0 kg（N）·hm^-2,262.5 kg（N）·hm^-2 and 300.0 kg（N）·hm^-2 respectively.The results show that the rate of nitrogen fertilizer application has a significant effect on grain yield.Between 0 ~ 300 kg（N）·hm^-2 nitrogen fertilization,indica hybrid rice yield initially increases to its maximum at 262.5 kg（N）·hm^-2,and then drastically decreases at 300 kg（N）·hm^-2.Relation between N application rate and grain yield follows a uni-peak curve,peaking at 11 355 kg·hm^-2 grain yield of 262.5 kg（N）·hm^-2,with the most apparent yield-increasing effect at 150-225 kg（N）·hm^-2.The important factor for yield difference with different N application rates is variations in the number of spikelet which has a significant direct correlation with N application rate（r = 0.963 5＊＊）.Nitrogen fertilizer application markedly affects the population quality of indica hybrid rice.Appropriate N application rate enhances LAI and grain-leaf area ratio of mid-season indica hybrid rice,and also maintains higher rates of leaf dry-matter and blade weight per shoot at heading stage.This is conducive for increasing plant photosynthetic capability and dry-matter accumulation at the late stage,apparently enhancing conversion rate of dry-matter after heading,while keeping plants from early senescence and increasing lodging resistance at the late stage with high agronomic nitrogen utilization efficiency.The recommended amount of applied N for mid-season indica hybrid rice（for a super-high yield） in Jianghuai Region is 262.5 kg（N）·hm^-2.