Wild oat (Avena fatua L.) biotypes resistant to acetolactate synthase and acetyl-CoA carboxylase inhibitors in Poland

Abstract

The aim of the study was to collect seeds of wild oat from the fields where, in spite of the applied herbicides, the weed is very poorly controlled, and to determine under greenhouse conditions if any resistant biotypes are present. In the years 2008-2011, 34 samples of wild oat were collected from fields where the weed was poorly controlled. The biotypes were analyzed in greenhouse experiments to determine if they are resistant to herbicides. Among five resistant biotypes three of them (R3, R4 and R5) were resistant only to iodosulfuron and mesosulfuron, and biotype R2 - only to propoxycarbazone-sodium. Biotype R1 exhibited multiple resistance to iodosulfuron + mesosulfuron and pinoxaden. The use of sulfometuron proves that the mechanism of resistance of two biotypes of wild oat (R1 and R4) to acetolactate synthase inhibitors is associated with target-site mutation. The curve of biotypes R3 and R5 controlled with iodosulfuron + mesosulfuron shows a relatively low resistance index and control of those biotypes with sulfometuron indicates a metabolic resistance.

Keywords

• herbicides
• resistance index
• multiple resistance
• target-site mutation