Critical Thinking about Biotechnology:
Genetically Modified Crops

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A. Environment

The issues:
Sustainable Resources
Weed Management
"Outcrossing"

The issue: Sustainable Resources

Farmers need to keep the soil healthy so they can continue to grow food crops now and for future generations. How does using GM canola and implementing other farm practices impact the soil?

Ernie's Perspective:
“The land that I farm has been in my family for two generations. I want to leave the soil in better condition than when we first bought the farm. We are working on improving the soil right now by not tilling. Tilling the soil has been a common practice for generations of farmers to prepare the soil for planting seed. Because tillage loosens the soil, when the soil dries it can be easily blown away. As well, water can wash away topsoil, the most nutrient-rich part. When you don't till the soil, you let the dried plant material on the soil shield it from wind and water erosion. These are two benefits of what producers commonly refer to as no-till.”

Geoff's Perspective:
“It's important that I am, and all other farmers are, committed to keeping the environment healthy because it provides us with our livelihood. In recent years I have been able to use GM canola to reduce the volume of pesticides our farm uses each year. In addition GM canola has allowed me to control a number of weeds to a fuller extent than previously possible. Also, by using reduced tillage operations I have been able to leave more organic matter in the soil, reduce erosion, cut fuel costs and put a few more dollars in our pocket.”

Kelvin's Perspective:
“Our goal is to leave the land healthier than when we started. We are stewards of the land and we need to preserve the land for future generations. In the 1930's we had one to two meter high sandbanks in the tree rows and everyone worked the land so much that the topsoil just turned to dust and blew away. Currently, we have a continuous crop rotation and erosion is virtually eliminated and we have refrained from removing tree lines to help slow the wind down. This way, we also maintain the wildlife and microclimates that form around the tree rows and that are beneficial for cropping. We cannot forget that we are only occupying a small amount of time in history; therefore, we need to be responsible.”

Zenneth's Perspective:
“In the 1980's soil was being blown from fields that had been tilled excessively that you could not see across the road. While I was growing up, and even in our early years of farming, we tilled our soil to control weeds and to replenish it with nitrogen. In the past, producers also burned the crop stubble of the previous crop, but it affected the health of the soil. Because most of the soil on our farm has a clay texture, if it rained after seeding, the surface would crust over and the seedlings would not be able to emerge from the ground.

At this point, we decided that we needed to put organic matter back into the soil to reduce soil erosion. We accomplished this goal by buying an air seeder to plant our crops with minimal soil disturbance. This practise maintained the straw on the soil for protection from wind and water erosion. I am currently making a modification to our air seeder, which will allow me to apply all nutrients at the time of seeding so that there will be minimal soil disturbance prior to seeding. At the end of the day, a producer relies on the soil because that is how we make our living and in order to make a living, we have to take care of those components that help us produce crops, which in turn are used to make food.”

Examine the impact of agriculture on the environment by looking at different indicators of sustainability at: www.agr.gc.ca/policy/environment/pubs_sds_e.phtml

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The issue: Weed Management

Integrated Pest Management (IPM) relies on many different tools to combat pests, including diseases, insects and weeds. For example, weeds compete with canola plants for light, moisture and nutrients. Controlling weeds ensures that the canola plant will produce a healthy crop. Farmers use integrated pest management tools to effectively control weeds and limit the impact on the environment.

Ernie's Perspective:
“Most canola producers around the world use herbicides to keep weeds from over growing their fields. Herbicides are chemicals developed and rigorously tested to control weeds, but not harm the canola plant. Farmers can choose from among more than forty different herbicides. The fact that farmers have a wide variety of herbicides to choose from is a good thing because different weeds require different herbicides. Because I grow several hundred hectares of canola, I made the decision that using herbicides is the most cost-effective way for me to control weeds.”

Geoff's Perspective:
“Each field on our farm is different, varying in type of soil, amount of moisture, as well as weed spectrum. As with most farms around the world the control of weeds remains one of our most serious concerns. GM canola has provided me with one more tool to reduce weed populations on my farm. All pesticides/herbicides used today have been rigorously tested to ensure that they have little or no environmental impact. All pesticides/herbicides come with strict instructions for use and handling to ensure that any environmental impact they may have is kept to a minimum.”

Kelvin's Perspective:
“We utilize crop scouting to evaluate what pests, including weeds and insects, are particularly problematic, and to see how many weeds we have per square meter. We can then determine the best management practice to control these pests. We find that within our operation, a lot of pests move in from the roadside ditch so we try to get out into the field to spray on the periphery of the field. To date, we generally obtain 75 to 80 per cent control on the existing pests through minimal pesticide use.

We also practice herbicide rotation along with our crop rotation. We feel that this is imperative in ensuring that weeds do not become resistant to herbicides that are currently on the market.”

Zenneth's Perspective:
“Before the development of herbicide tolerant (HT) canola, we had to spray our fields a few times a year to control weeds so that our crop would grow to its full potential. Through biotechnology, scientists have developed a canola crop that can survive herbicides that would normally harm the canola plant. We can now control difficult weeds in our canola crop that we were not able to control in the past with less herbicide.

We also grow forages and some fall seeded crops such as winter wheat in our crop rotation. By seeding at different times, the weeds have a difficult time competing with the crop and we get better weed control. Having a crop that will cover the ground quickly is important for this method of weed control and genetically modified (GM) canola seems to fit quite well into this system.”

For an overview of the decisions a canola grower has to think about when choosing pest control, go to: www.canola-council.org/ and follow the links from the Growers' Manual to Canola Pests.

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The issue: "Outcrossing"

Outcrossing is a normal, natural occurrence in plants. It occurs when genes are transferred from one plant of a species to another plant of the same species, and in some cases to a closely related but different plant species. Outcrossing can occur between non-GM plants, as well as between GM plants and non-GM plants.

What would happen if there was outcrossing between a genetically engineered plant and a wild relative? Could traits that may be desirable in a crop plant such as drought tolerance or tolerance to herbicide be transferred to a wild relative, making the offspring of these plants increasingly difficult to control?

These are the very questions that Canadian regulators ask before they approve a GM plant for release into the environment. For the most part, GM plants that have been approved for release in Canada do not have wild relatives. This includes, for example, potatoes, tomatoes, corn, soybeans and flax.

It is important to know that the potential for outcrossing is addressed on a case by case basis, considering the plant species, its biology and ecology in Canada, and the GM trait.

Ernie's Perspective:
“Bees carry pollen from one plant to another. Some plants need bees to carry pollen for them to produce seeds, while other plants don't. It depends on the biology of the plant.

GM canola contains genetic material that allows the plants to be resistant to herbicides. The genetic material is also in the pollen so bees that come to a GM canola plant and then go to another plant can move the genetic material through pollen. But it's important to remember that pollen is compatible only within a very limited number of plant species. For example canola is a relative of the wild mustard weed. As a result pollen from canola can fertilize wild mustard flowers to produce seeds that may have the herbicide tolerant trait. We rotate our crops to ensure that any wild canola relatives are controlled by herbicides and other weed-control practices.”

Geoff's Perspective:
“Prior to being released into the environment all GM crops are given a very thorough environmental safety assessment in which they are considered in the context of their environment. This ensures that the possibility of outcrossing is very low. I have developed a rotation, which further limits the possibility of outcrossing. By rotating fields between various varieties of GM canola, as well as conventional canola, I can greatly limit the chance of any type of GM weed developing.”

Kelvin's Perspective:
“I believe that the risk of GM crops outcrossing with non-GM crops is minimal because each crop is genetically predisposed to pollinating other crops of its own species. Although I am concerned about weeds becoming herbicide tolerant I believe that canola is more likely to pollinate with other canola plants rather than weeds, even if they are within the same species. However, if herbicide tolerant (HT) canola varieties are grown too close together, they may pick up traits from other varieties and become tolerant to all available herbicides. At this point, the canola would not be controllable by any herbicide and could be a difficult weed to control in other crops such as wheat. Currently, we only grow one HT crop at a time and we keep them isolated from other crops. The general rule of thumb as a foundation seed grower is to allow a minimum of 600 meters between crops. When we grow GM canola we take extra care because these crops are excellent tools. But like any tool, we must use them responsibly. Government regulations have been put in place to help producers be responsible users of new technologies.”

Zenneth's Perspective:
“Since I am growing some identity preserved (IP) crops, I am especially concerned about outcrossing between genetically-modified (GM) crops and non-GM crops. I am even more concerned about what my neighbour may be growing because maintaining neutral boundaries around GM and non-GM crops is important. To limit the potential of outcrossing between GM and non-GM crops, we keep a minimum distance between fields. Communication with neighbours about planting areas is also an effective way to limit outcrossing potential.”

Canada's regulatory system evaluates many factors before any GM crops are released into the environment.

Activity:
List the environmental factors from the text and other sources. Discuss the tools available to farmers for addressing environmental concerns.

Teacher's Notes: