Roundup Ready is a trademark owned by Bayer (formerly known as Monsanto) for a specific type of genetically modified seeds. These seeds are designed to resist damage from a herbicide called Roundup, which contains the chemical glyphosate. Because these products are widely used, the term "Roundup Ready" is sometimes used more generally to describe any genetically modified seeds that are resistant to herbicides, even if they are not made by Bayer.
History
In 1996, genetically modified soybeans called Roundup Ready soybeans, which are resistant to a herbicide called Roundup, became available for sale. In 1998, Roundup Ready corn was also introduced. Today, Roundup Ready crops include soybeans, corn (maize), canola, sugar beets, cotton, and alfalfa. Wheat is still being developed for this trait. More details about Roundup Ready crops can be found on the GM Crops List. By 2005, 87% of U.S. soybean fields were planted with soybean varieties resistant to glyphosate, the active ingredient in Roundup.
The use of Roundup Ready or glyphosate-resistant seeds has caused some weeds to become resistant to glyphosate. While the number of resistant weeds is small, the number of resistant weed species is increasing quickly, creating challenges for farmers who depend on these seeds for controlling weeds.
In 2016, to address the growing problem of glyphosate-resistant weeds, Monsanto released a new type of soybean called Roundup Ready Xtend. These soybeans can tolerate both glyphosate and another herbicide called dicamba. In 2016, Xtend soybeans were planted on 1 million acres, and by 2020, it was expected that they would be planted on 50 million acres.
Although the use of Roundup Ready crops has increased the amount of herbicides applied per acre, it has also changed the types of herbicides used. Farmers now use fewer herbicides like atrazine, metribuzin, and alachlor, which are more likely to enter runoff water. Because glyphosate can be sprayed directly on Roundup Ready crops during the growing season, farmers using these seeds are less likely to till and spray their fields during the off-season. This practice reduces soil erosion, lowers labor costs, and helps maintain soil moisture.
In September 2010, a court order in the case of Center for Food Safety v. USDA stopped farmers from planting Roundup Ready sugar beets until an environmental impact report was completed, causing some concern about a possible sugar shortage. In 2012, the USDA finished its study and concluded that Roundup Ready sugar beets are safe. After this, the crops were allowed to be planted again.
Patents
The US patent for Roundup Ready soybeans ended in 2014. The US patent for Roundup Ready canola ended on April 26, 2022. The 2020 movie Percy tells the story of Canadian farmer Percy Schmeiser's legal battle with Monsanto over the Roundup Ready canola patent.
Genetic engineering
Some microorganisms have a form of the enzyme 5-enol pyruvylshikimate-3-phosphate synthase (EPSPS: EC 2.5.1.19) that is not affected by glyphosate. This form was found in the bacteria Agrobacterium strain CP4 (called CP4 EPSPS) and was resistant to glyphosate. Scientists took the CP4 EPSPS gene and inserted it into soybean plants. To help the gene work in soybean cells, scientists added a special part of the gene called a chloroplast transit peptide from the petunia EPSPS. This transit peptide was chosen because it had been shown to help similar genes reach the chloroplasts of other plants. The gene was placed into a plasmid called PV-GMGTO4. This plasmid included three bacterial genes, two copies of the CP4 EPSPS gene, and a gene from Escherichia coli that makes an enzyme called beta-glucuronidase (GUS), which was used as a marker. Scientists used a method called the particle-acceleration method, or "gene gun," to insert the DNA into soybean cells. The soybean variety A54O3 was used for this process. Scientists checked if the gene was successfully added by testing for GUS activity. This was done using a staining method where the GUS enzyme changes a colorless substance into a blue color. Plants that showed blue color were tested for glyphosate tolerance by spraying them with glyphosate. Scientists observed how well the plants survived over many generations.
Productivity claims
In studies designed to test only how genetic changes affect crop yields, Roundup Ready soybean lines have shown lower yields compared to top conventional varieties. In 1999, a study found that Roundup Ready soybeans had a 6.7% lower yield than the best traditional soybean varieties. This lower yield, called "yield drag," happens in the same way as when other traits are added to soybeans through traditional breeding methods. Monsanto claims that later patented versions of these soybeans produce 7-11% more than their original versions, closer to yields seen in traditional farming. However, the company does not provide specific yield numbers. In a 2006 application to the USDA, Monsanto stated that the RR2 variety (mon89788) produces 1.6 bushels less per acre than A3244, the conventional soybean variety used as a base for the genetic modification.
Many genetically engineered crops show similar changes in yield. Roundup Ready crops experience two issues: "yield drag," where the genetic modification itself reduces yield, and "yield lag," where delays in adding the best new yield improvements to Roundup Ready lines slow progress.
These tests are often done in controlled, artificial conditions, which do not reflect real-world farming situations where weeds grow densely. In actual fields, the benefits of Roundup Ready crops in controlling weeds are more noticeable.