Abstract: Pot and field experiments were conducted to study the effects of mixed-planting of different rice varieties on germination and growth of barnyardgress(Echinochloa crus-galli var.mitis).Rice varieties Xiushui 63(allelopathic index 0.24,low competitive),PI312777(allelopathic index 0.61,high competitive) and Guodao 1(allelopathic index 0.55,high competitive) were used.In the pot experiment PI312777 and Guodao 1 showed strong inhibition but Xiushui 63 had no effects on the germination of barnyardgrass under monoculture.However,the germination rate of barnyardgrass was significantly reduced in the pots mixed planted Xiushui 63 with PI312777 or Guodao 1.Both pot and field experiments showed that the biomass of barnyardgrass was significantly lower in pots or plots of PI312777 and Guodao 1 than in Xiushui 63 under monoculture.Moreover,the biomass of barnyardgrass was significantly decreased in the pots or plots of Xiushui 63 mixed-planting with PI312777 or Guodao 1.The results suggested that mixed-planting of rice varieties could enhance the resistance of Xiushui 63 to barnyardgrass.

Key words: rice, barnyardgrass, mixed-planting, allelopathy

摘要： 以秀水63（化感指数为0.24，竞争力弱）、PI312777（化感指数为0.61，竞争力强）、国稻1号（化感指数为0.55，竞争力强）为材料，采用盆栽试验和田间试验相结合的方法，研究了抗草潜力不同的水稻品种混种对稗草萌发和生长的影响。盆栽试验结果表明，PI312777和国稻1号对稗草萌发抑制作用显著，而秀水63对稗草萌发无抑制作用；秀水63与PI312777或国稻1号混合种植后，稗草的萌发均受到抑制。盆栽和田间试验均表明，在单种情况下，稗草的生物量在PI312777和国稻1号的试验小区均低于秀水63的试验小区。秀水63与PI312777、秀水63与国稻1号混合种植，稗草的生物量均显著降低。与抗草潜力高的水稻品种（PI312777和国稻1号）混合种植，在一定程度上能增强秀水63对稗草的抑制能力。

关键词: 水稻, 稗草, 混合种植, 化感作用