Herbicide-tolerant mustard gives farmers more opportunity and flexibility in the field

Carinata (Brassica carinata) is an attractive oilseed cultivar that is used for industrial applications such as biofuels and lubricants while yellow mustard (Sinapis alba) is in high demand from the food industry for its role as a popular condiment in North America and around the world. Yet, there are limited options for producers when it comes to broad-leaf weed control in these valuable crops.

Mustard 21 Canada Inc., through its membership in the Diverse Field Crops Cluster (DFCC), and Agriculture and Agri-Food Canada (AAFC) are working towards the goal of non-GMO herbicide-tolerant mustard varieties for Canadian producers. A non-GMO approach is important for access to European markets.

Herbicide-tolerant crops allow farmers to control weed infestations that can have detrimental impacts on crop performance. Scientists Christina Eynck and Bifang Cheng are working with carinata and yellow mustard to develop varieties that are tolerant to Group 2 herbicides (acetolactate synthase inhibitors or ALS inhibitors).

Both carinata and yellow mustard are susceptible to Group 2 herbicide residues in the soil from applications in the previous year which limits the number of acres available to plant carinata and yellow mustard. Herbicide-tolerant varieties will give farmers more options in crop rotations and open up more acres for mustard crops. 

“Prairie farmers are used to using herbicide technologies,” Eynck says, “They are more willing to adopt a new crop or new cultivar of an established crop if they know they can spray it to control the weeds.”

Group 2 herbicides inhibit the activity of the ALS enzyme that plants need to synthesize branched-chain amino acids—and it isn’t selective. Without this enzyme, any susceptible plant will die—whether a weed or a valuable crop plant. In herbicide-tolerant varieties, a mutation in the ALS gene prevents the herbicide from acting upon the enzyme, allowing the plant to grow and thrive even after herbicide application.

Cheng and Eynck are hoping to develop resistant cultivars through seed mutagenesis experiments. First, they treat the seed with ethyl methanesulfonate (EMS), a compound that causes random mutations in the seed’s genome. After the treatment, they grow the mustard plants, and then spray them with the Group 2 herbicide to identify the tolerant mutants.  

But both mustard types have their challenges.

“What makes working on carinata a bit more complicated is that it has two genomes from its ancestors,” Eynck says, “you actually need to combine resistance genes out of both genomes to get commercial levels of tolerance.” So far Eynck is half-way there: she is currently on the quest for the resistance gene on the second genome.

Yellow mustard brings another challenge: thick mucilage in its seed coat makes it difficult for the EMS compound to get inside the seed. “We have to think of ways to get rid of the mucilage and increase efficiency of seed mutagenesis,” says Cheng.

Herbicide-tolerant crops are important for a producer’s ability to control weeds efficiently, maintain high yields, and utilize all acres of land for production of diverse crops. Group 2 herbicide-tolerant mustard crops will give producers more options to maximize farm profitability.

Written by Erin Matthews

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

The Diverse Field Crops Cluster (DFCC) is a unique alliance of industry partners: Canadian Hemp Trade Alliance, Canary Seed Development Commission of Saskatchewan, Saskatchewan Flax Development Commission, Smart Earth Camelina Corporation, Manitoba Crop Alliance, Mustard 21 Canada Inc, and Northern Quinoa Production Corporation. DFCC aligns industry and research stakeholders to seize market opportunities and accelerate the acreage and market returns of special crops. Ag-West Bio leads this five-year research cluster which is funded by Agriculture and Agri-Food Canada’s Canadian Agricultural Partnership program and industry partners.