Roundup Ready crops are resistant to:
Roundup Ready is brand name for transgenic crops tolerant to glyphosate based herbicide Roundup. Native crop EPSPS inhibited by glyphosate application, blocking aromatic amino acid synthesis. Incorporation of insensitive EPSPS variant allows continued pathway function despite spray, enabling post-emergence weed control without crop injury. Crops carrying cp4-epsps gene survive broadcast over-the-top application at commercial rates, simplifying weed management and facilitating conservation tillage reducing soil erosion. Soybean, cotton, maize, canola, alfalfa, and sugar beet versions deregulated globally. Resistance not based on detoxification but target site insensitivity, so herbicide still translocates systemically killing weeds. Development of Roundup Ready revolutionized agriculture in late 1990s, dominating transgenic acreage. Stewardship challenges include evolution of glyphosate resistant weeds after continuous monoculture and reliance on single mode of action. Therefore Roundup Ready crops are resistant to glyphosate herbicide through expression of tolerant EPSPS enzyme. Adoption history began 1996 with Roundup Ready soybean event GTS 40-3-2 developed by Monsanto, followed by cotton, maize. Global planted area exceeded 90 million hectares for soybean alone by 2018. Benefits include flexibility of post-emergence weed control and enablement of no-till preserving soil moisture and reducing erosion. Concerns about herbicide over-reliance led to development of stacked herbicide tolerance with dicamba and
Ref: Dill GM Crops 2005 Roundup Ready; Funke PNAS 2006 CP4; NCBI NBK131103; ISAAA Pocket K 10 herbicide tolerance mechanism.