玉米田两种阔叶杂草藜及苍耳对草甘膦的敏感性测定

苍耳Xanthium strumarium和藜Chenopodium album是常见的两种阔叶杂草,其在玉米田发生严重,影响了玉米的生长和产量。本文利用整株生物测定法对我国东北及黄淮海玉米产区采集到的苍耳及藜种群对草甘膦的敏感性进行了测定。种子室内培养至5~6叶期,喷施草甘膦后14 d称量鲜重,计算抑制杂草种群50%个体生长的草甘膦剂量(GR 50)。草甘膦对10个苍耳种群GR 50在54.87~249.75 g/hm^2,平均值为(111.53±20.02)g/hm^2,均低于450 g/hm^2(1/2倍推荐剂量),表明10个苍耳种群均对草甘膦敏感;草甘膦对33个藜种群GR 50范围在97.05~920.86 g/hm^2,平均值为(313.88±24.70)g/hm^2,93%的种群GR 50低于450 g/hm^2,表明绝大多数藜种群对草甘膦比较敏感,仅发现一个藜种群GR 50大于900 g/hm^2(田间推荐剂量),表明其对草甘膦具有一定耐受性。

Sensitivity of two broadleaf weeds Xanthium strumarium and Chenopodium album to glyphosate in corn fields

Xanthium strumarium and Chenopodium album are two common broad-leaf weeds, and their occurrence seriously affected corn growth and reduce yield in corn fields. In our study the whole plant bioassay was used to determine the sensitivity to glyphosate of ten populations of X.strumarium and 33 populations of C.album collected from two major corn producing areas, Northern China and Huanghuaihai. The seeds of two weeds were sowed in greenhouse, and the glyphosate was applied at the 5-6 leaf stage of the weeds. 14 days after glyphosate application, fresh weight of plants was weighted and GR50 values were calculated, respectively. GR50 values of glyphosate to ten populations of X.strumarium ranged from 54.87 to 249.75 g/hm2 with the average value of (111.53±20.02)g/hm2, which were lower than 450 g/hm2 (1/2 recommended dose), showing that all populations of X.strumarium were sensitive to glyphosate. Among C.album populations, GR50 values ranged from 97.05 to 920.86 g/hm2 and its average value was (313.88±24.70)g/hm2. The GR50 values of 93% C.album populations were less than 450 g/hm2, indicated that the vast majority of C.album populations were sensitive to glyphosate. And only one population of C.album showed a GR50 value of above 900 g/hm2 (recommended dose), indicating that it had a certain degree of tolerance to glyphosate.