Induction effect of some weeds on the allelopathy of rice varieties

Induction on the allelopathy in four rice varieties were analyzed with three weed species [barnyardgrass (Echinochloa crusgalli L.), flatsedge (Cyperus difformis), ducksalad (Monochoria vaginalis Burm.f)]. The results showed that the allelopathic potential of Gaojiaozijingdao, HG1 and DV86 were significantly larger than that of Yangdao No.6 under the weed control. When rice was co-grown with the weeds the inhibiting effects of allelopathic rice varieties on barnyardgrass (Echinochloa crusgalli L.) was significantly changed. When grown with barnyardgrass HG1 had the highest inhibiting effect on the weed, even significantly higher than that of Gaojiaozijingdao, which had stronger allelopathy under the weed control. When cultivated with ducksalad (Monochoria vaginalis Burm.f), DV86 showed strongest allelopathic potential on barnyardgrass. It suggested that weed species could induce the allelopathic potential in rice, and this induction might be specific among weed species and rice varieties.