为了探明直播条件下播种量对不同千粒重杂交稻产量形成特点和干物质生产特性的影响，以雅5优2199（小千粒重）和内6优103（大千粒重）为材料，于2017年采用人工撒播栽培方式在四川德阳进行不同播种量（7.5、15.0、22.5、30.0、37.5 kg/hm2）大田试验。结果表明，不同播种量对杂交稻产量影响显著，有效穗数和干物质量随播种量的增加而增加，而每穗粒数呈下降趋势，播种量对结实率、千粒重和收获指数影响不显著。雅5优2199产量随着播种量增加呈先增加后下降的趋势，以播量为22.5 kg/hm2的处理最高，达10.86 t/hm2，较播量为7.5 kg/hm2的处理增加了20.53%，差异显著；内6优103产量以播量为37.5 kg/hm2的处理最高，达10.82 t/hm2，较播量为7.5 kg/hm2的处理增加了11.20%，差异显著；2个品种在15.0、22.5、30.0、37.5 kg/hm2播量时，处理间产量差异均不显著。不同千粒重杂交稻之间的产量差异不显著。综合考虑产量和种子成本，小千粒重杂交稻的适宜播种量为15.0~22.5 kg/hm2，大千粒重杂交稻的适宜播种量为22.5~30.0 kg/hm2。

In order to clarify the effects of seeding amount on yield formation and characteristics of biomass production of hybrid rice with different thousand grain weight under direct seeding condition, a field experiment was conducted with different seeding amount （7.5, 15.0, 22.5, 30.0 and 37.5 kg/hm2） by artificial broadcasting in Deyang city in 2017, using Ya 5 you 2199（YY2199）with low thousand grain weight and Nei 6 you 103 （NY103）with high thousand grain weight as materials. The results showed that, the effect of seeding amount on the yield of hybrid rice was significant, panicles per m2 and biomass production of hybrid rice showed an increasing tendency with seeding amount increasing, spikelets per panicle of hybrid rice showed a decreasing tendency with seeding amount increasing. The effect of seeding amount on seed setting rate and thousand grain weight were not significantly. The grain yield of YY2199 firstly increased and then decreased with seeding rate increasing, the yield was highest when the seeding amount was 22.5 kg/hm2, which reached to 10.86 t/hm2, the yield was increased by 20.53% compared with the treatment of 7.5 kg/hm2. The yield of NY103 was highest when the seeding amount was 37.5 kg/hm2, which reached to 10.82 t/hm2, the yield was increased by 11.20% compared with the treatment of 7.5 kg/hm2. However, there were no significant difference in grain yield between seeding amount treatment 37.5 kg/hm2 and the other three seeding amount treatment （15.0, 22.5, 30.0 kg/hm2）. There was no significant difference in yield between different thousand grain weight varieties. The optimum seeding amount of hybrid rice with low and high thousand grain weight was 15.0~22.5 kg/hm2 and 22.5~30.0 kg/hm2, respectively, in consideration of both grain yield and seed cost.