Herbicide Tolerance in Mustard

Despite mustard’s $120 to $140 million annual contribution to the Canadian economy, acres on the Prairies have remained steady for several years. One major challenge limiting producer uptake is the lack of registered herbicide options for managing hard-to-kill broadleaf weeds such as wild buckwheat, narrow-leaved hawk’s beard, redroot pigweed and Russian thistle. These weeds affect yield and grain quality through weed seed contamination.

Carinata is a dedicated industrial oilseed being developed for the Canadian Prairies. Although it is currently not grown in Canada, the economic opportunity for carinata as feedstock for the emerging bioeconomy is substantial. To be a viable choice in their rotations, growers will need varieties that are suitable for current production methods.

Christina Eynck and Bifang Cheng, research scientists at AAFC Saskatoon Research & Development Centre, along with industry partners Nuseed Canada and Mustard 21 Canada Inc., are bringing herbicide tolerant innovations to mustard and carinata breeding.

“The lack of herbicide options for small acreage crops like mustard and carinata is a gap. Most new technologies developed by multinationals are for larger crops,” explains Eynck.

An aggravating factor is that pulse and cereal production rely heavily on Group 2 herbicides to which mustard and carinata are highly susceptible. This limits the number of available acres suitable for carinata and yellow mustard production in the years following a pulse or cereal rotation.

This research marks the first step in development of mustard and carinata varieties tolerant to Group 2 herbicides.

This project, funded through DFCC, is focused on developing non-GMO, herbicide tolerant yellow mustard (Sinapis alba) and carinata (Brassica carinata) varieties that are tolerant to Group 2 herbicides.

Researchers are using seed mutagenesis to develop yellow mustard and carinata germplasm with Group 2 herbicide resistance. This will o er a much-needed alternative strategy for growers to manage weeds not controlled by currently registered herbicides.

“Our goal is to develop varieties that are resistant to Group 2 herbicides, which will provide growers some in-crop weed control and the option to re-crop mustard and carinata where soil residual Group 2 activity remains,” says Eynck.

Acetolactate synthase (ALS) is an enzyme found in microorganisms and plants. Blocking ALS by Group 2 herbicides leads to stunting, malformation and/or death. Mutations in the ALS gene, occurring naturally or induced through mutagenesis, are known to prevent Group 2 herbicides (ALS inhibitors) from working and thus render plants herbicide tolerant. Through this work, Eynck and Cheng have been able to develop carinata and yellow mustard germplasm with increased tolerance to the Group 2 herbicide, Solo (an imidazolinone (imi)).

“This is a significant achievement for both crops as it represents the first step in the development of imi-tolerant varieties,” states Eynck.

Chemical and physical mutagenesis of seed followed by selection under herbicide pressure was used in the study. This technique has been utilized to develop several herbicide tolerant crops and does not classify as genetic modi cation (non-GMO). Therefore, herbicide tolerant crops developed this way move through the regulatory process easier and have wider public acceptance. This will be important for developing Canadian acres as the European biofuel market is increasing its demand of non-GMO feedstocks.

“We are now working on pyramiding different herbicide tolerant genes, developed at AAFC and also Nuseed,” says Eynck. “Our next step is to develop different combinations of herbicide tolerant ALS genes so we can test them against a range of Group 2 chemistries in the field.”

This DFCC research activity is led by Agriculture and Agri-Food Canada-Saskatoon Research and Development Centre and
Mustard 21 Canada Inc. with funding support from Agriculture and Agri-Food Canada’s Canadian Agricultural Partnership
program, Saskatchewan Mustard Development Commission, Canadian Mustard Association and Nuseed Canada Inc.