Herbicide-resistant rape directive breeding method based on acetolactate synthase (ALS) target esterase

The invention provides a herbicide-resistant rape directive breeding method based on acetolactate synthase (ALS) target esterase, which belongs to a plant trait breeding method. The method comprises the following steps of selecting materials needed by production of rape or breeding of the rape, processing seeds with ethylmethane sulfonate (EMS), mutagenizing the seeds to be isolated and propagated to a M2 generation, and directionally screening herbicide-resistant mutant characters in a large group under the selection pressure of the herbicide adopting the ALS as the target esterase. In order to increase the probability for acquiring the mutant characters, the directive screening can be continuously conducted in multiple years, or conducted in multiple places in the same year or conducted in multiple places in multiple years until the needed mutant material is screened out.