Wild mustard is a diploid (2n = 18) annual winter weed that can reduce crop yields by between 48 % and 71 %. This weed is nowadays resistant to acetolactate synthase and even to new herbicides. In an experiment with wild mustard with suspected resistance to Pyroxsulam herbicide, seeds were collected and planted in a pot in a growth chamber. Five concentrations of Pyroxsulam herbicide were applied when the wild mustard had developed 2 to 3 leaves. After 2 weeks of herbicide application, 2 leaves sterilised with 70 % ethanol were sampled. Sequence analysis of the ALS gene detected twenty target site mutations in ORF1 and ORF3 with amino acid substitutions. ALS gene mutations were detected at multiple codons, with the highest mutation frequency at 1.08 % Pyroxsulam concentration. Significant differences between concentrations used in the study and single-nucleotide polymorphisms were found in ORF1, ORF3 and combinations of the two fragments. The herbicide concentrations were indicated to play a significant role in nucleotide substitutions in wild mustard. This herbicide dose-response experiment confirmed that wild mustard resisted the Pyroxsulam herbicide. This is the first report of such mutations in wild mustard from Kurdistan, Iraq.
