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DD2004-46: Determination of the Safety of the BASF Canada Imidazolinone-Tolerant Lentil Line RH44

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Issued: 2004-06

Appendix 1: BASF CLEARFIELD Lentil Stewardship Plan

BASF is committed to the long-term sustainability of the CLEARFIELD Production System. The stewardship initiatives BASF have in place with other commercial CLEARFIELD crops are evidence to support this claim. In Canada, the sustainability of the CLEARFIELD Production System for canola is protected with the CLEARFIELD Commitment. In the United States growers wishing to produce CLEARFIELD wheat must agree to the terms and conditions outlined in the BASF CLEARFIELD Wheat Stewardship Grower Agreement. These agreements ensure that certain stewardship practices are followed to help protect and prolong the usefulness of this technology.

BASF will ensure a similar stewardship initiative is followed when CLEARFIELD lentils become a commercial reality.

Key Recommendations of CLEARFIELD Lentil Stewardship:

Crop Tolerance

BASF has the diagnostic tools and protocols necessary to assist the lentil breeder with development of CLEARFIELD lentil varieties. Data to substantiate crop tolerance of herbicide tolerant crops is a key component of the variety registration process. CLEARFIELD lentil stewardship will ensure herbicide tolerance is maintained.

Inseparable seed

The large seed size of lentils helps to minimize the possibility of inseparable seed. Cleaning and management of lentil seed is easier in this respect compared to a crop such as canola, where weeds such as cleavers are the same size as canola seed. The use of Certified seed helps reduce the spread of weed seed and seed borne diseases.


As mentioned earlier, the potential for out-crossing in lentils is very low. Lentil is highly self-pollinating, and the frequency of out-crossing is less then 0.5%. This low frequency of out-crossing combined with crop rotation practices, poor competitive ability of lentils and sensitivity to numerous herbicides will ensure any tolerant survivors are destroyed.

Herbicide Resistance

BASF will outline specific recommendations to help prevent the development of weed resistance as a result of the CLEARFIELD lentil production system. These recommendations will be in line with the current agronomic production practices for lentils and based on the background material highlighted earlier. These recommendations will include:

Utilize crop rotation

The crop rotation recommendations in the lentil producing region of the province are based on moisture limitations and cultural practices for disease management. Lentil is recommended in the rotation 1 out of 4 years. This will allow for the use of herbicides with an alternate mode of action.

Use herbicides with different modes of action

Limit the sole reliance of ALS-inhibiting herbicides to no more than 2 out of 4 years unless other control practices are implemented on target weed species. The use of imi-herbicides is a function of the crops grown in a specific region. With less canola in the region and Pursuit not registered for use on brown or dry brown soils, the lentil growing region cropping practices help manage use of imi herbicides.

Where applicable, use sequential or tank mix partner herbicides with multiple modes of action. For example, Assert (imi-herbicide for cereals) is registered as a tank mix with phenoxy products such as 2,4-D and MCPA. This serves to broaden the weed control spectrum and the combination of herbicides with two different modes of action is an effective resistance management strategy.

Properly manage weeds in crop-fallow rotation

As indicated earlier, in the brown or dry brown soil climatic zones in particular, Summerfallow is a common production practice. In the fallow year, growers should control weeds through the use of tillage or burndown (non-ALS) herbicides.

Volunteer CLEARFIELD Lentils

Typical crop rotation practices were highlighted earlier. These typical crop rotations are followed because of limitations of soil moisture in the area of lentil production and for disease management. Therefore cereal crops, primarily spring and durum wheat are the main rotational crops in the lentil growing region. Dry conditions and relatively high temperatures in the region limit canola production in the area where lentils are grown.

There are a number of factors that contribute to volunteer lentils rarely being an agronomic concern. The low probability of volunteer lentils being significant agronomically is reflected in the CFIA guidelines for conducting confined trials. The period of post-harvest land use restriction is one year when conducting confined lentil trials. The period of post-harvest land use restriction is much longer with other crops that volunteer plant management is a significant issue. A number of factors contribute to volunteer lentils not being an agronomic concern. These factors include:

Lentil pods shatter some of their seeds on the ground, even if the crop is harvested in a timely manner. However, two factors limit the potential for volunteer lentils in a subsequent season to producing the crop. Firstly, lentil has relatively low seed production per plant, when compared to a crop such as canola. Secondly, lentil seeds germinate readily in the presence of moisture and so very few lentil seedlings survive as weeds in the succeeding crop.

If lentil seed survives and germinates during the subsequent season, the tiny, slow growing lentil seedlings compete poorly with other cultivated crops or weeds. This is especially true when volunteer lentils are trying to compete with a competitive, rapidly growing crop such as wheat. Consequently, volunteer lentils do not pose any significant management issues. If volunteer lentils did survive and were present the year following production, numerous non-ALS herbicide options are currently available that will control volunteer CLEARFIELD lentils.

Herbicides from a variety of Herbicide Groups (4,6,9) are effective in controlling volunteer lentils. Herbicide Group 4 represents growth regulator herbicides such as 2,4-D, Attain, Banvel II, Buctril M, Champion Plus, Curtail M, DyVel, DyVel DS Embutox, Estaprop, MCPA, Mecoprop, Prestige, Prevail, Target and others.

Herbicide Group 6 contains photosynthetic inhibitors (nitriles/benzothiadiazoles). Herbicides such as Buctril M and Pardner are representatives of this group. Herbicide Group 9 contains the herbicides that inhibit EPSP synthase. Roundup, Vantage Rustler and Touchdown are representatives of herbicides in this group. Herbicide market share information on cereal crops is available through the Cereal Broadleaf Herbicide Usage and Image Study – 2002, published by Stratus Agri-Marketing. The study reports herbicide usage in cereal crop production by soil zone and herbicide groups. In 2002 products from Herbicide Group 4,6 and 9 represented 85 and 85% of the total application acres made in the dark brown and brown soil zones, respectively.

From a stewardship or best management practice standpoint, BASF would not recommend CLEARFIELD lentils be grown following CLEARFIELD wheat. While this is not recommended from a weed resistance point of view, in a situation where it did occur, weed management tools are available for the control of herbicide tolerant volunteers.

As stated earlier, BASF would not recommend or promote these type of crop rotation practices.

The following points highlight the main tenets of the Stewardship Program for the CLEARFIELD Production System:

CLEARFIELD Production System – Obligatory Actions

There are a number of aspects that must be understood and followed by Agronomists and Growers when using CLEARFIELD Production Systems.

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