Roundup-Ready Crops
*This web page was created by Lane Estes and Graham Watson for Biology 361, an undergraduate course at Davidson College*
 
 
 
 
 
 

 


What is Roundup?
Glyphosate, otherwise known as Roundup, is a broad-spectrum herbicide used to kill crop weeds since Monsanto introduced it in 1974. This herbicide can effectively kill “a wide variety of annual and perennial grasses, sedges, broad-leaf weeds, woody shrubs, and commercial crops” (Mendelson, 1998). In 1994, approximately 26 million pounds of Roundup was used in the United States alone, which equates to 1.2 billion dollars in sales. However, studies have shown that Roundup sales have continued to increase by as much as 20 percent per year for the last several years, so this figure is an underestimate of Roundup’s current sales figures (Mendelson, 1998).


How Does Roundup Work?
Glyphosate kills such a huge assortment of different weeds and plants by inhibiting the creation of EPSP synthase, an enzyme in plants that is required to synthesize the amino acid phenylalanine (Kliener, 1998). Deprived of phenylalanine, plants cannot make the proteins that it needs, so these plants weaken and eventually die. Glyphosate is harmless to humans since the human body does not produce its own phenylalanine. Instead, the human body acquires all of the necessary phenylalanine from ingested food (Wade, 1999).

What Are Roundup-Ready Crops?
In the past, a farmer had to carefully monitor the amount of Roundup applied to his fields because too much Roundup would not only kill the weeds, but also kill the desired crop. With Monsanto’s introduction of genetically modified “Roundup-Ready” crops, farmers can plant these new glyphosate resistant crops and use Roundup without fear of destroying these transgenic plants. Monsanto engineered Roundup-Ready crops by inserting a gene derived from a petunia that produced large amounts of EPSP synthase. This inserted gene produces so much EPSP synthase that it overwhelms the EPSP inhibition caused by glyphosate (Let us Spray, 2000).

Monsanto has already produced and marketed Roundup-Ready soybeans, canola, cotton, and corn. Roundup-Ready crops currently cover over 33 million acres worldwide. Monsanto also plans to introduce Roundup-Ready sugar beets, wheat, and potatoes.



© Copyright 2002 Department of Biology, Davidson College, Davidson, NC 28035
Send comments, questions, and suggestions to: laestes@davidson.edu or grwatson@davidson.edu