Evolution of herbicide resistance in weeds: initial frequency of target site-based resistance to acetolactate synthase-inhibiting herbicides in Lolium rigidum

• Published in: Heredity 2002-01, Vol.88 (1), p.8-13
• Main Authors: Preston, C, Powles, S B
• Format: Article
• Language: English
• Subjects: Acetolactate Synthase - antagonists & inhibitors; Acetolactate Synthase - metabolism; Biological Evolution; Biomedical and Life Sciences; Biomedicine; Cytogenetics; Drug Resistance - genetics; Ecology; Evolutionary Biology; Herbicides; Herbicides - pharmacology; Human Genetics; Imidazoles - pharmacology; Lolium - drug effects; Lolium - enzymology; Lolium - genetics; Niacin - analogs & derivatives; Niacin - pharmacology; Plant Genetics and Genomics; research-article; Sulfonylurea Compounds - pharmacology
• ISSN: 0018-067X; 1365-2540
• DOI: 10.1038/sj.hdy.6800004

The frequency of individuals resistant to two acetolactate synthase (ALS)-inhibiting herbicides in three previously untreated populations of Lolium rigidum was determined. The frequency of individuals resistant to the sulfonylurea herbicide sulfometuron-methyl varied from 2.2 × 10 −5 to 1.2 × 10 −4 and the frequency of individuals resistant to the imidazolinone herbicide imazapyr varied from 1 × 10 −5 to 5.8 × 10 −5 depending on the population. Application of sulfometuron-methyl selected individuals with a herbicide-insensitive ALS, which was also cross-resistant to imazapyr. The high initial frequency of individuals resistant to ALS-inhibiting herbicides in L. rigidum populations never previously exposed to these herbicides helps explain the rapid evolution of herbicide resistance in this species once ALS-inhibiting herbicides were used.