Stewardship of plants with novel traits
What is a plant with novel trait (PNT)?
The Canadian Food Inspection Agency (CFIA) defines a plant with a novel trait (PNT) as a new variety of a species that has one or more traits that are novel to that species in Canada. A trait is considered to be novel when the trait is:
- new to the plant species in Canada, and
- has the potential to have an impact on environmental safety.
The CFIA assesses the safety of plants with novel traits in Canada. This assessment must take place no matter what process has been used to introduce the novel trait, whether it be genetic engineering, mutagenesis, conventional breeding, or any other method. This focus on plants with novel traits, instead of selected methods of production, means the CFIA may assess the safety of a broader array of products than do other countries.
- Safety Assessment Process for Novel Foods and Agricultural Products of Biotechnology
- "Novelty" and Plants with Novel Traits.
What does "stewardship" mean?
Stewardship is the careful and responsible management of something under one's care. This can include a product or the use of a technology.
The Canadian Food Inspection Agency (CFIA) applies this concept to PNTs. In the case of PNTs, there is a need to pay attention to the entire life-cycle of these products — including the part that follows product assessment and approval for environmental release.
The CFIA defines a stewardship plan as a document that outlines how the product or technology will be managed, or under what conditions it will be used. The CFIA requires stewardship plans for some types of PNTs.
For what PNTs are stewardship plans submitted as part of the safety assessment?
The CFIA requires developers to address the post-approval part of a product's life-cycle. Product developers may do this through stewardship plans. Product developers must support the implementation of these plans and farmers have to comply with the requirements under these plans. The CFIA aids in the development, use, and monitoring of the stewardship plans.
Two examples of stewardship plans that product developers are asked to submit to the CFIA as part of the safety assessment are; stewardship plans to prevent the development of insects resistant to insect-resistant crop plants, and stewardship plans to prevent the development of herbicide resistant weeds, control herbicide tolerant volunteers and reduce the occurrence of volunteers with resistance to multiple herbicides.
What are some examples of insect-resistant plants?
One widely-used insecticide is Bacillus thuringiensis (Bt), a naturally occurring bacterium that is found in soil. This bacterium produces a toxin that can work as an insecticide. Bt is effective for the control of several insects, such as flies, mosquitoes, Colorado potato beetles, and corn borers.
Farmers have been using Bt since the 1920s, and it has been commercially available since the 1950s. More recently, plants have been developed to produce a Bt protein, enabling the plant itself to resist certain insect pests. Plants genetically modified to express the Bt protein are capable of resisting certain insect pests (as opposed to farmers spraying this insecticide on their crops to protect them). Currently, in Canada, corn and potatoes expressing the Bt protein have been approved for unconfined environmental release.
What are insect resistance management plans?
An insect resistance management (IRM) plan is a stewardship plan to delay the development of resistance of insects to plants expressing pesticidal properties; that is, to delay the evolution of a susceptible insect population into one that is no longer controlled by a pesticide.
Insects developing resistance to pesticides is not unique to biotechnology-derived plants. Scientists have long known that such resistance can only be delayed and managed, but not avoided altogether. The IRM plans are designed to delay the development of resistance in insect populations. In the case of plants that have been developed to be resistant to certain insect pests, such as Bt corn, the IRM plans require a refuge strategy.
The refuge strategy involves exposing one portion of the insect population to Bt corn plants, while maintaining another part of the insect population in an area (a "refuge") planted with non-Bt corn. This is done by planting, in blocks or strips, a certain percentage of the area of a commercial field with unsprayed varieties not expressing the Bt protein. This allows one portion of the susceptible insect population to survive and mate with resistant individuals in the insect population, thus delaying the development of a resistant population.
What are herbicide tolerance management plans?
Similar to insect resistance, where an insect becomes resistant to a pesticide, plants may become resistant, or tolerant, to certain herbicides after repeated exposure to the herbicide. This means weeds can become resistant to herbicides, leaving farmers with fewer options to control weeds. This could result in a farmer tilling the field, which increases soil erosion, or using more herbicides to control the weeds.
Herbicide tolerance management (HTM) plans are designed to delay weeds and species related to a herbicide-tolerant crop plant from developing tolerance to herbicides. HTM plans are also designed to address the occurrence of herbicide tolerant volunteers and volunteers with resistance to multiple herbicides.
What is included in a HTM plan?
An effective HTM plan is expected to include, but is not limited to, elements such as:
- guidelines for rotation of crops and chemicals
- identification of potential changes in usual farming practices that could result in reduced agricultural sustainability
- an efficient way to allow growers to report any problems they have while growing the crop
- a monitoring plan to assess the effectiveness of the stewardship plan and to identify areas that need improvement
Are stewardship plans effective?
Stewardship plans are part of a strategy to monitor and manage long-term environmental effects of certain crop plants. They also serve as information tools for farmers.
Compliance with stewardship plans is being monitored by the CFIA and its partners. Evaluations done to date indicate a high compliance rate. For example, evaluations of farmer compliance with Bt corn stewardship plans are done on behalf of the Canadian Corn Pest Coalition (CCPC). The results of these can be found on the CCPC website.
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