增密减氮对不同类型水稻品种颖花形成的影响

Effects of Dense Planting with Reduced Nitrogen Application on Spikelet Formation of Different Types of Rice Varieties

为了明确增密减氮栽培对不同类型水稻品种颖花形成(分化与退化)的影响以及颖花形成与产量的关系,在大田条件下采用裂―裂区试验设计,以籼粳杂交稻(甬优4949)、超级杂交籼稻(扬两优6号)和常规籼稻(黄华占)为供试材料,设置正常氮肥(180kg/hm^(2))和减氮(90kg/hm^(2))2个施氮水平,正常密度(30cm×15cm)和增密(20cm×15cm)2个移栽密度处理。结果表明,减氮轻微降低了3个品种的二次枝梗数、颖花分化数和颖花现存数,但差异均不显著;而增密显著降低了颖花分化数和颖花现存数。一次枝梗数、二次枝梗数和幼穗分化期干物质积累对颖花分化数贡献较大。就颖花生产效率而言,增密减氮能有效增加氮素、积温和辐射颖花生产效率,有利于单位面积总颖花数的提高。与扬两优6号和黄华占相比,甬优4949在增密减氮栽培下具有较高的幼穗分化期干物质积累量、颖花生产效率和颖花分化数,从而形成了大的库容,获得了高的产量。

In order to clarify the effects of dense planting with reduced nitrogen application on spikelet formation(differentiation and degeneration) of different types of rice varieties and the relationship between spikelet formation and yield, a field experiment with three rice varieties(Yongyou 4949, the indica-japonica hybrid variety;Yangliangyou 6, the super hybrid indica variety;Huanghuazhan, the inbred indica variety), two N levels(90 and 180kg/ha) and two planting densities(30cm×15cm and 20cm×15cm) were conducted in a split-split plot arrangement. The main results showed that the number of secondary branches, differentiated spikelets and surviving spikelets per panicle were slightly decreased caused by reduced nitrogen rate, but the differences were not significant. However, dense planting significantly reduced the number of differentiated spikelets and surviving spikelets per panicle. The number of primary and secondary branches, dry matter accumulation at panicle initiation stage contributed more to the spikelet formation. The spikelet production efficiency for nitrogen, accumulated tempearature and accumulated radiation were effectively improved under dense planting with reduced nitrogen application. Compared with Yangliangyou 6 and Huanghuazhan, Yongyou4949 had higher grain yield under dense planting with reduced nitrogen application, which was attributed to its higher dry matter accumulation, spikelet production efficiency and differentiated spikelets.