TEACHING ALL VOLUMES SUBMIT WORK SEARCH TIEE
VOLUME 2: Table of Contents TEACHING ISSUES AND EXPERIMENTS IN ECOLOGY
ISSUES: FIGURE SETS

Figure Set 4: Glyphosate Tolerant Soybeans

Purpose: To examine the usefulness of Roundup ready soybeans as compared to conventional varieties, analyzing both yields and herbicide use rates.
Teaching Approach: "formal group work"
Cognitive Skills: (see Bloom's Taxonomy) — comprehension, analysis, synthesis
Student Assessment: concept mapping

BACKGROUND

Soybeans are one of the staples in our diet. They are used in many foods such as pancake mix, margarine, and crackers. They are also used as animal feed. In 2002, U.S. soybean production was 2.73 billion bushels, compared to 9.01 billion bushels of corn and 1.62 billion bushels of wheat. Therefore soybeans certainly are a significant part of the U.S. agricultural product. With the revolution of modern biotechnology tools, the prospect of improving soybean crop yields while using less chemical pesticide use became a possibility. Between 1995 and 1996, biotech soybeans were approved for sale by the Food and Drug Administration (FDA), making biotech crops agriculture’s most rapidly embraced technology (CBI 2002).

Monsanto is a pesticide producer that entered the biotechnology market. They produce Roundup which contains the active ingredient glyphosate. Glyphosate is an herbicide that, when applied to foliage, prevents the plant from producing an essential amino acid. This in turn reduces the production of protein in the plant which results in inhibited plant growth. Monsanto’s product, Roundup Ready soybeans, which are resistant to glyphosate, were planted on one million acres in 1996 (Simon 2001). The use of these modified soybeans grew quickly. In 1997, 17 percent of farmers’ soybean acreage was from genetically modified seeds (Stokes 2002).

As a result of the increased use of glyphosate tolerant soybeans, the use of this herbicide has increased. Glyphosate is considered a less toxic herbicide when compared to others seeking similar results and therefore, is considered one of the safer herbicides. Although this herbicide has become more popular, the question of whether biotechnology will actually decrease the need for herbicides in the long run is still undetermined.

One problem associated with the use of any chemical to kill an organism is the ability of that organism to build resistance. Resistance occurs when those organisms that survive, despite their contact with a chemical, pass on their genes to future generations. They are able to survive because of genetic strengths. Those that cannot survive contact with that chemical will die and those with the genes that can survive will continue passing along the beneficial genes. This problem can be seen in current situations, such as mosquito resistance to various chemicals traditionally used to kill them.

The first two figures in this Figure Set are USDA data on increased use of genetically modified soybeans plus use of herbicides in soybean fields over the same time period. The third figure compares yields for Roundup Ready and conventional soybeans.


Literature cited:

Simon, S. 2001. Biotech soybeans plant seed of risky revolution. Los Angeles Times 1 July 2001.

Stokes, B. 2002. Avoid a food fight with Europe. National Journal 34.44: 3228.

Council for Biotechnology Information. 2002. Council for Biotechnology Information 4 Nov. 2002. http://www.whybiotech.com.

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