A polynucleotide is provided, comprising at least a first region encoding a first protein capable of conferring on a plant, or tissue comprising it, resistance or tolerance to a first herbicide, and a second region encoding a second protein likewise capable of conferring resistance to a second herbicide, with the provisos (i) that the polynucleotide does not encode a fusion protein comprising only a 5-enol-pyruvyl-3-phosphoshikimate synthetase (EPSPS) and a glutathione S transferase (GST); (ii) that the polynucleotide does not comprise only regions encoding superoxide dismutase (SOD) and glutathione S transferase (GST); and (iii) that the polynucleotide does not comprise only regions encoding GST and phosphinothricin acetyl transferase (PAT).