Evolutionary

Herbicide tolerant crops (HTC)

• Increased use of herbicide can result in increase in development of weed resistance to that herbicide either through exposure or through gene flow
• hybridisation (as a result of gene flow) with wild relatives may lead to the development of super weeds in farm or other environments ie weeds that are harder to eradicate
• possible pleiotropic effects of the transgenes or gene interactions may alter traits such as seed dormancy, germination, tolerance to biotic or abiotic stresses leading to increasing weediness or conversely decreasing fitness.
• HTC have a selective advantage in a farm or managed environment where herbicides are used (become a selection pressure).
• no selective advantage for HTC in natural environments (as there are no herbicides in natural environments)