Question: how can crossbreeding help save a type of crop plant

title: Plant breeding
text: The majority of commercially released transgenic plants are currently limited to plants that have introduced resistance to insect pests and herbicides . Insect resistance is achieved through incorporation of a gene from Bacillus thuringiensis ( Bt ) that encodes a protein that is toxic to some insects . For example , the cotton bollworm , a common cotton pest , feeds on Bt cotton it will ingest the toxin and die . Herbicides usually work by binding to certain plant enzymes and inhibiting their action . The enzymes that the herbicide inhibits are known as the herbicides target site . Herbicide resistance can be engineered into crops by expressing a version of target site protein that is not inhibited by the herbicide . This is the method used to produce glyphosate resistant crop plants ( See Glyphosate )