ABSTRACT

Herbicide dose-responses of seedling progenies of Ranunculus acris populations varying in herbicide exposure history indicate that this weed has evolved multiple resistance to phenoxycarboxylic acid and acetolactate synthase (ALS)-inhibitor herbicides. To test the hypothesis that this ‘multiple-resistance’ can occur in the same plant, we conducted an experiment where 11 clones of R. acris, varying in parental population exposure to these two mode-of-action herbicides, were treated with full- and half-label doses of MCPA and flumetsulam. Aminopyralid and glyphosate (pyridine carboxylic acid and 5-enolpyruvylshikimate 3-phosphate (EPSP) synthase-inhibitor mode-of-actions respectively), both with label recommendations for R. acris, were included for comparison. Two clones, both from the same field population exposed historically to MCPA and to flumetsulam, and with anecdotal records of field control failures, were unaffected by flumetsulam and many plants survived treatment with MCPA, providing conclusive evidence for multiple herbicide resistance to these two herbicides in the same R. acris individuals. By contrast, there was no evidence among the 11 clones for resistance to either aminopyralid or glyphosate (86-100% mortality in all clones). The herbicide-resistant and -susceptible clones of R. acris provide a unique opportunity to investigate the biochemical mechanism(s) and genetics of phenoxycarboxylic acid and ALS-inhibitor resistance in this species.

摘要

不同除草剂暴露史的毛茛种群幼苗后代的除草剂剂量反应表明，这种杂草已经进化出对苯氧羧酸和乙酰乳酸合酶 (ALS) 抑制剂除草剂的多重抗性。为了检验这种“多重抗性”可以在同一植物中发生的假设，我们进行了一项实验，其中 11 个R. acris 克隆，在亲本群体中暴露于这两种作用模式除草剂的情况不同，用全-和半标签剂量的 MCPA 和氟美舒仑。Aminopyralid 和草甘膦（吡啶羧酸和 5-enolpyruvylshikimate 3-phosphate (EPSP) 合酶抑制剂的作用模式分别），均附有R. acris的标签建议, 用于比较。两个克隆，都来自历史上暴露于 MCPA 和氟美舒兰的同一田间种群，并且有田间控制失败的轶事记录，不受氟美舒兰的影响，许多植物在 MCPA 处理后幸存下来，为多种除草剂对这两种除草剂的抗性提供了确凿的证据。相同的R. acris个体。相比之下，在 11 个克隆中没有证据表明对氨基吡啶或草甘膦具有抗性（所有克隆的死亡率为 86-100%）。R. acris的除草剂抗性和易感克隆提供了一个独特的机会来研究该物种中苯氧羧酸和 ALS 抑制剂抗性的生化机制和遗传学。