Coexistence of target-site and non-target-site mechanisms of glyphosate resistance in Amaranthus palmeri populations from Argentina

Amaranthus palmeri S. Waston is currently one of the most problematic weeds worldwide. Biotypes with resistance to herbicides such as glyphosate and ALS inhibitors are now present in almost all Argentinian cultivable areas. In this work, we studied three different populations, some them previously characterized resistant inhibitors. Dose-response curves were conducted order assess effect on survival dry biomass populations. Subsequently, presence target-site (TSR) was studied. Results confirmed showing levels resistance, being R2 R3 significantly more than r1 population. A high prevalence P106S substitution detected while none increase relative EPSPS copy number noticed. Some surviving plants without any TSR mechanisms for population, suggesting non-target-site (NTSR).