A Study on Tolerance to Pretilachlor in Eight Species of Echinochloa

Height of seedlings, length of leaf and coleoptile cells, and a -amylase activities of eight species or varieties of barnyardgrass （Echinochloa） were measured after seeds being treated with pretilachlor. There existed obvious differences in the tested traits among the materials. The inhibition rate of pretilachlor to Echinochloa crusgalli （L.） Beavu. var. mitis （Pursh.） Peterm was the lowest, and that to E colonum （L.） Link was the highest among the eight species or varieties of barnyardgrass. It suggested that the different species or varieties of barnyardgrass possess variable tolerance to pretilachlor.