Establishment Of A Weed Inhibit Ring For Evaluation Of Rice Allelopathic Potential

In order to establish a weed inhibit ring method for evaluating allelopathic rice accessions, anallelopathic rice PI312777was employed as donor plants and barnyard grass (Echinochloa crusgalli) was used as receiver plant. The rice and barnyardgrass were pot-cultured together in paddysoil under natural conditions. The main results are summarized as follows:(1) At the space of6cm from rice to barnyard grass, the inhititory effect of rice on barnyardgrass growth was increased as the increase of rice leaf stage. There were significant differentsamong3-,4-, and5-leaf stages of allelopathic rice. However, there was no significant differentsbetween5-and6-leaf stages. Therefore,5-leaf stage of allelopathic rice PI312777was chosen inthe weed inhibit ring method to screen the allelopathic rice.(2) At5-leaf stage of allelopathic rice PI312777, there were no significant different among3years results when at the different spaces from rice to barnyardgrass. The inhibitory effects of riceon barnyard grass growth were descreased as the increase of spaces from rice to barnyardgrass. Atthe space12cm from rice to barnyard grass, the inhititory rates of rice on barnyard grass growthwas as high as50%. Therefore, the space12cm from rice to barnyard grass was chosen in theweed inhibit ring method to screen the allelopathic rice.(3) The weed inhibit ring method was30kg paddy soil in a pot (51cm diameter,16cmheight) mixed with10L water and standing for1day. Six uniform pre-germination rice seedsplanted in the central of pot. Weeds were hand-remove. At the5-leaf stage of rice,6uniformpre-germination seeds of barnyard grass planted at equal distance in the ring of12cm from therice seedlings. No rice seedling was as control. After7days, the inhibitory rates of rice on rootlength, plant height and plant dry weight of barnyard grass were calculated for evaluation of riceallelopathic potential.(6) The allelopathic potential of40rice accessions were evaluated by the weed inhibit ringmethod. The results showed that PI312777and Taichung Native1were allelopathic rice accessions.And38out of40rice accessions were no alleloapthic rice accessions.