Herbicides used in conjunction with a specially designed, herbicide tolerant crop
Complementary herbicides for herbicide tolerant plants developed with genetic engineering are generally "non-selective" or "broad-spectrum" herbicides. These affect central sites of plant metabolism and are thus effective against a wide range of plants.
An herbicide tolerant crop and its respective complementary herbicide constitute an herbicide tolerance (HT) system (also known as an herbicide resistance (HR) system). In this combination, wide-spectrum herbicides like Liberty or Roundup can be applied to kill nearly all weeds without harming the crop.