Abstract: A field experiment was conducted to compare tillering dynamics, dry matter accumulation, yield and yield components between late rice grown under machine transplanting with high hill density and single seeding per hill （MTHS） and conventional mechanized transplanting （CMT）, using hybrid rice cultivars Taiyou 390 and Longjingyou 1212. Four levels of seeding ages （15, 20, 25 and 30 d） were set for each machine transplanting method. The results showed that the tiller number was higher under CMT that under MTHS, while panicle-bearing tiller percentage under MTHS was 18.36% higher than that under CMT. Spikilets per panicle and secondary branches per panicle under MTHS were 21.00% and 26.92% higher than those under CMT, respectively.Dry matter accumulation was lower under MTHS than under CMT at mid-tillering, higher under MTHS than under CMT at both full heading and maturity. Single shoot dry matter accumulation under MTHS was higher than that under CMT by 0.02g, 0.11g and 0.37g, at mid-tillering, full heading and maturity, respectively. Grain yield under MTHS was 10.08%, 11.08%, 18.64% and 20.07% higher than that under CMT at seedling age of 15, 20, 25 and 30 d, respectively. The study indicated that MTHS could enhance single tiller performance by reducing unproductive tillers, increase sink size by increasing secondary branches per panicle, improve dry matter production after full heading, and consequently increase grain yields.

Key words: late-season hybrid rice, machine transplanting with high hill density and single seedling per hill, seedling age, dry matter, grain yield

摘要： 以杂交稻泰优390和隆晶优1212为材料，开展大田试验，在不同秧龄（15、20、25和30 d）下对单本密植机插和常规机插杂交晚稻的分蘖动态、干物质积累、产量及产量构成进行了比较。结果表明，在各秧龄下，单本机插的处理分蘖数均少于常规机插，但成穗率、每穗粒数和二次枝梗比常规机插平均高18.36%、21.00%和26.92%；单本机插分蘖中期的干物质积累量低于常规机插，但齐穗期和成熟期的干物质积累量要高于常规机插；单本机插分蘖中期、齐穗期和成熟期的单茎干物质量分别比常规机插高0.02 g、0.11 g和0.37 g；单本机插在15、20、25和30 d秧龄下的产量分别较常规机插高10.08%、11.08%、18.64%和20.07%。由此可见，杂交晚稻采用单本密植机插，有利于控制无效分蘖，形成个体优势，增加二次枝梗数，扩大库容量，提高齐穗后群体干物质量，进而获得高产。

关键词: 杂交晚稻, 单本密植, 机插, 秧龄, 干物质, 产量