In this study, the effects of acetochlor on the growth of 16 rice varieties were investigated. In addition, the sensitivity of different rice variety to acetochlor and the relationship between sensitivity and variety type were also studied. The effects of acetochlor on the germination of rice were determined in Petri dishes. The inhibitory effects of acetochlor on the seedling height, root length, seedling weight, root weight and other indicators of rice varieties were determined by agar method. The result showed the acetochlor had a certain inhibitory effect on the germination of rice. The low-concentration acetochlor would increase the seedling height and root number. However, when the concentration of acetochlor reached a certain value, its inhibitory effects became obvious. The inhibitory effect of acetochlor on rice roots was stronger than that on rice stems. Among the rice varieties, Sidao had the highest acetochlor tolerance, and Tianyou 3301 had the highest sensitivity to acetochlor. The average inhibition rates of seedling height, fresh seeding weight, root length, fresh plant weight and root number of Sidao in agar culture medium with 0.02 mg/L of acetochlor were 1.46%, 6.42%, 51.06%, 60.87% and -6.45%, respectively, while of Tianyou 3301 were 21.62%, 22.62%, 63.16%, 74.76% and 3.89%, respectively. The sensitivity to acetochlor differed significantly among different rice variety. However, this difference had no significant relationship with variety type.
