Abstract: The growth character of barnyardgrass [Echinochloa crusgalli (L.) Beauv. var. mitis (Pursh) Peterm.] in mixture transplanting with different morphological type rice varieties (combinations) were studied. The hybrid rice combination Ⅱ you 2070 with the plant morphological type of long stalked and great canopy (LSGC) reduced the plant height, leaf area index, plant dry weight, panicle length, tiller number and spikelets per panicle of barnyardgrass significantly in the transplanted rice. The competitive ability of LSGC with barnyardgrass was more powerful compared with the plant morphological type of middle stalked and medium canopy (MSMC) and the plant morphological type of short stalked and small canopy(SSSC). The yield components of indica hybrid rice with LSGC was no decrease markedly under barnyardgrass interference of 50 plants per square meter. However, the yield components of japonica rice with SSSC declined seriously resulting in 40 percent loss of grain yield.

Key words: rice, plant morphology, barnyardgrass, biological competition, weed control

摘要： 以不同株型的水稻品种(组合)为材料研究了混栽其中的无芒稗［Echinochloa crusgalli(L.) Beauv.var.mitis (Pursh) Peterm.］的生长状况。高秆大冠层株型水稻品种Ⅱ优2070显著降低移栽稻田无芒稗株高、叶面积指数、植株干物质、分蘖数、穗长和穗粒数。水稻对无芒稗的竞争力，以高秆大冠层株型最强，中秆中冠层株型次之，矮秆小冠层株型最弱。在无芒稗50株/m2干扰下，高秆大冠层株型水稻各产量因子下降不明显，而矮秆小冠层株型粳糯稻各产量因子显著下降，平均减产40%。

关键词: 水稻, 株型, 无芒稗, 生物竞争, 杂草防治