Occurrence of non-target-site-based resistance to ALS inhibitors in the broadleaf weed Papaver rhoeas (corn poppy).

The vast majority of reported cases of resistance to ALS inhibitors in broadleaves is due to the selection of mutant, herbicide-resistant ALS alleles carrying a mutation at one of a few ALS codons that can be easily identified (ALS-based resistance). Non-ALS-based resistance (non-target-site resistance, NTSR), considered to be endowed by differences in the expression of many genes, has essentially been reported in grasses and hardly ever in broadleaves. We investigated NTSR to ALS inhibitors in poppy by pairing plants resistant to ALS inhibitors with susceptible plants and subsequently analysing the segregation of resistance in F1 families. Poppy plants resistant to ALS inhibitors were geno…