不同种植密度和品种对夏玉米物质生产和产量构成的影响

以郑单309、郑单326、郑单958和中玉303等玉米品种为研究对象，在7个种植密度（6.00×10⁴、6.75×10⁴、7.50×10⁴、8.25×10⁴、9.00×10⁴、9.75×10⁴和10.50×10⁴株/hm²）条件下进行田间试验，研究不同种植密度和品种对夏玉米生育期内群体物质累积量和产量构成的影响。结果表明，高密度下株高和穗位高表现出明显优势，中玉303和郑单958的株高和穗位高表现相对较高。随生育期推进，植株群体干物质量显著增加，花前、花后和成熟期干物质量均随密度增加而显著增加，成熟期中玉303和郑单958的干物质量较郑单326和郑单309平均提高16.1%，花后干物质量占成熟期的比重以6.00×10⁴株/hm²密度处理下最高，为58.68%，以郑单958最高。随密度增加，成熟期千粒重显著下降，产量明显提高，10.50×10⁴株/hm²密度处理最高，为14.49t/hm²，中玉303产量最高，较郑单309和郑单326平均增加16.3%。由此可见，在本试验条件下，选用中玉303，以10.50×10⁴株/hm²密度种植，可提高玉米植株花后物质生产量，促进花后物质分配，实现夏玉米高产。

Effects of Different Planting Densities and Varieties on Dry Matter Production and Yield Components of Summer Maize

Four maize hybrids, Zhengdan 309 (ZD309), Zhengdan 326 (ZD326), Zhengdan 958 (ZD958) and Zhongyu 303 (ZY303), with seven planting densities including 6.00×10⁴, 6.75×10⁴, 7.50×10⁴, 8.25×10⁴, 9.00×10⁴, 9.75×10⁴ and 10.50×10⁴ plants/ha were set to analyse the effects of planting densities and varieties on dry matter production and yield formation of summer maize. The results indicated that higher plant height and ear height were obtained under the higher density treatments, and the plant heights and ear heights of ZY303 and ZD958 were higher. Plant dry matter production was increased with maize growth. The production before and after anthesis and maturity stage were also improved with increasing of planting densities. The dry matter was significantly increased by 16.1% in ZY303 and ZD958 than in ZD326 and ZD309. The treatment of 6.00×10⁴ plants/ha got the highest ratio of dry matter in post-anthesis to maturity stage, and the ratio was the highest in ZD958. With the increase of planting densities, the 1000-grain weight was decreased while grain yield was improved at maturity stage. The highest yield (14.49t/ha) was found in the 10.50×10⁴ plants/ha treatment, and yield of ZY303 was increased by 16.3% than that in ZD309 and ZD326. It was concluded that the combination of ZY303 with the density of 10.50×10⁴ plants/ha could improve the post-anthesis dry matter production and biomass distribution, and to increase maize yield.