The present invention refers to method for producing a transgenic plant with increased herbicide tolerance or resistance as compared to a corresponding non-transformed wild type plant, comprising transforming a plant cell or a plant cell nucleus or a plant tissue with a nucleic acid molecule encoding an Alopecurus cytochrome P450 monooxygenase, as well as to the nucleic acid, and plants with increased herbicide tolerance or resistance comprising the nucleic acid of the invention. Furthermore, the present invention refers to methods of controlling weeds at a locus which contains a plant with increased herbicide tolerance or resistance comprising the nucleic acid of the invention.