It turns out that it was just a wake-up call, but one that Meghan Vankosky and other research scientists at Agriculture and Agri-Food Canada (AAFC) in Saskatoon chose not to ignore.

“There was a worry that swede midge would become a significant pest here,” says Vankosky. “Luckily, swede midge is not on the Prairies right now but, because it’s such a devastating insect pest, there is definitely a concern that it could be invasive to the Prairies and that it could survive here.”

It’s not often that agriculture has this kind of lead time to solve a problem, so with funding from Western Grains Research Foundation, the Saskatchewan Canola Producers’ Commission and the Saskatchewan Ministry of Agriculture, the team in Saskatoon set to work on a project designed to better understand swede midge ecology in the Prairie environment, and potential avenues to protect against it.

What a swede midge wants

Specifically, the research team wanted to find out which plants swede midge prefer to colonize, what (if any) resistance those host plants offer, the basis of that resistance, and what makes plants susceptible to swede midge damage in the first place.

“This was all lab work,” says Vankosky, explaining that finding swede midge’s behaviour and preferences requires some very controlled environments.

As with many crop pests, there is usually more than one potential host and, as swede midge is adapted to brassica species, Vankosky and the team collected 12 such plant species to test. One was canola itself, and the remaining 11 were other crucifer crops and common brassica weeds, such as flixweed, ball mustard, two types of false flax and more.

To find out which of these plants female swede midge most preferred for egg-laying, researchers conducted a series of choice and no-choice tests where insects were exposed to all 12 plants at once, or exposed to only one plant type at a time. Plants were then examined for the presence and number of eggs on them, as well as larval development.

Vankosky says what they found was that, given a choice, swede midge will pretty much lay eggs on any brassica plant, except for flixweed. Not unexpectedly, they showed a marked preference for canola and mustard (with an average of nearly 500 eggs per plant), while stinkweed and wild mustard were fairly low on their “likes,” both averaging well under 10 eggs per plant. Flixweed? Zero eggs per plant.

But it’s the results of the no-choice tests that reveal the imperative to reproduce. “In these tests, swede midge either have to accept the host plant or not,” says Vankosky, adding that they mostly held their noses and laid eggs on less-favoured hosts in the absence of any other option. “So even if they don’t like a certain plant much, they’ll still use it to lay eggs.” Even stinkweed, which averaged just over two eggs per plant in the choice tests, was accepted as a host in the no-choice test with an average of 40 eggs per plant. Interestingly, swede midge would still not lay any eggs on flixweed.

“The plant host range does seem to be very broad,” says Vankosky, adding that this finding confirms that, should swede midge establish on the Prairies, managing it will be difficult.

Where lies the resistance?

So, what has flixweed got that other brassica hosts don’t? Why is it able to repel a swede midge desperate to lay eggs while other plants can’t? And not just flixweed, but some of the other plant hosts that were found to be less susceptible to swede midge damage overall.

Vankosky says that the team looked at several things, including biochemical factors such as glucosinolate levels, plant hormonal response to attack, and the genetics behind those responses. One thing they figured out for sure is that glucosinolates, which are toxic to many insects, are likely not a factor when it comes to a plant’s susceptibility to swede midge.

The team was able to identify just over 6,000 genes that are expressed during swede midge infestation, indicating that plants are trying to react and presumably protect themselves, but the exact nature and pathways of resistance are yet to be determined.

“In some ways, I think this is still a big black box,” says Vankosky. “In terms of resistance, there are a lot of different avenues we could take to further investigate this.”

Ultimately, how swede midge chooses a host and how those plants defend themselves through various biochemical, physical or genetic means is a larger conversation and the foundation for future research.

“We learned a lot by doing this research and we are in a good position to help ourselves if swede midge ever becomes a problem here,” says Vankosky, adding that this is always possible as our environment continues to change. “Swede midge tend to be introduced by people bringing it into an area without knowing it, at least that is one hypothesis for what happened in 2007 and 2008. If the weather is conducive to their survival, they’ll stay.”

The post Getting the jump on swede midge appeared first on Country Guide.

“Pathogens always evolve,” says André Laroche, a research scientist with Agriculture and Agri-Food Canada (AAFC) in Lethbridge. “In 2000 new isolates of the stripe rust pathogen developed the capacity to infect in drier, warmer conditions and were able to infect susceptible wheat all over the Prairies — the pathogen is very efficient at mutating and causing infection. Prior to 2000, there was no need to develop resistant cultivars for this pathogen outside the irrigated region of southern Alberta.”

Times have changed.

Resistance to stripe rust in Canadian wheat cultivars is fairly low and while work to develop resistant varieties is ongoing, stripe rust’s ability to quickly adapt to and overcome single-gene resistance makes this a long and complicated process. In other words, robustly resistant cultivars could take a while to get here. In the meantime, farmers are looking for other solutions now, and Laroche thinks he may have one.

“We wanted to find a way that’s simpler, faster and sensitive enough to detect stripe rust spores,” he says. The idea is that if farmers had a way of knowing if disease spores were present in sufficient quantities to cause infection, they could act more quickly to protect crops and prevent yield loss before visible symptoms of stripe rust set in, and spray only when necessary to preserve fungicide tools.

With funding from the Western Grains Research Foundation and the Saskatchewan Wheat Development Commission, Laroche and his team may have found a path forward.

A test that stands the test

Assays are complex to develop. In essence, they are analytical tools designed to measure the quantity or quality of a specific target using a specific reagent known to react only to that target and nothing else. So researchers needed a specific biological target — in this case stripe rust spores — and a specific biological reagent that accurately detects that target — an antibody that had already been developed through previous research.

That’s a massive oversimplification, but Laroche and his team were starting from a point of strength — they already had an antibody (well, two antibodies actually — a primary and a secondary). Stripe rust spores, specifically their DNA, were another matter.

Laroche explains that the goal was to develop a rapid assay that would detect the presence and quantity of stripe rust ureniniospores using highly sensitive DNA-based technology. (Ureniniospores are one of up to five spore stages in the rust life cycle and the forerunners of infection. If they are present, then visible symptoms of disease will inevitably follow within two to three weeks.)

The trouble is that to get at that DNA, the ureninio­spores must be cracked open, which is difficult because of their thick cell walls, and it’s even more challenging when they are not abundant. So the team developed two different yet complementary approaches that would lead them to a solution.

“In the direct assay, we linked the DNA to the primary antibody that recognized the stripe rust spores, and used that to multiply the signal,” says Laroche. “We also used an indirect way where we used a secondary antibody linked to the DNA reporter sequence to react with the first antibody to enable an indirect multiplication in the system.”

If that sounds complicated (and it does), what it boils down to is that researchers found a way to detect the target stripe rust without having to crack open the ureniniospores. And they did it by, as Laroche puts it, “interrogating the surface of the spore,” which allowed them to build an assay that detected interactions with proteins and other molecules found on the surface of ureniniospore cell walls. They ended up with an assay that clearly and reliably “lights up” or signals, when stripe rust ureniniospores are present.

So far so good, but the mere presence of stripe rust ureniniospores is only part of the equation. “How many ureniniospores need to be present for infection to occur?” asks Laroche. “It was a question we had for some time. There is no literature on that, so when we started, we didn’t know how many we needed to cause infection.”

As it turns out, as few as 1,000 to 100,000 ureniniospores floating around are enough to cause stripe rust infection. Those are small numbers when it comes to fungi where spores are often counted in the millions. So Laroche needed to make sure the assay being developed could detect very low levels of ureniniospores. “My biggest worry was whether it was going to be sensitive enough,” he says. The antibody tests showed that the assay could detect between 20 and 40 ureniniospores from different stripe rust isolates, proving the test was highly sensitive and therefore highly reliable.

Next steps

The main goal with all of this work is to protect wheat yield and also the fungicide tools farmers still have when it comes to stripe rust management. If you’ve heard it once, you’ve heard it a thousand times that infection occurs before visible symptoms develop, which is why preventive fungicide application has become common. But that has its downside.

“Everybody knows that spraying ‘in case’ is not a mid-term or long-term solution because the pathogen could develop resistance to the active ingredients,” says Laroche. “There are only two fungicide classes useful now against stripe rust, and the day you lose that ultimate tool, you’re in deep trouble. People are aware of it; there is a level of concern. They need to protect their future.”

The rapid-detection system Laroche and his team have developed can help farmers do that by letting them know if their wheat crop is in danger of being infected with stripe rust or not. Deploying it is the next hurdle.

“The assay is a little bit tricky,” says Laroche. “You need specialized equipment to read it. One way it could work is if farmers have a device to collect spores that they can send to a service lab for testing, and the lab could say we found them and how many, or say if it’s clean.”

Another idea is a larger program of aerobiological surveillance. “We could have an organization with detectors spread out across the land,” says Laroche. “There could be a reading of air samples once a week, and we could send an automated message to growers.” Those messages could let farmers know if they’re in a hotspot, for instance, or let them know there are not enough stripe rust spores to cause a problem in their area.

Right now, Laroche and the team at AAFC Lethbridge are working with farmers to figure out what approach will work best.

The post Detecting stripe rust in wheat before it strikes appeared first on Country Guide.

Well, you’re not alone. “There have been a lot more questions about fungicide resistance in the last two years than in the last 10,” says Troy Basaraba, a market development representative with Bayer in Brandon, Man.

There is a buzz of concern about fungicide resistance, but Mike Harding says the good news is that if you’re already employing best management practices to control herbicide resistance, you’re likely keeping fungicide resistance in check.

“The same principles and strategies that work for herbicide resistance will work for fungicide resistance,” says Harding, a research scientist in plant health with Alberta Agriculture and Forestry in Brooks, Alta. “Crop rotation is a really key piece, also good control of volunteers and weeds that might be hosts, and hopefully the message is getting out there that you shouldn’t apply half rates of fungicides and multiple applications of a single mode of action.”

If that sounds too simple and you’re waiting for a “but” here it is: if you don’t pay attention to managing for fungicide resistance now while the incidence is relatively low, we are laying the groundwork for worsening problems in the future. “No one wants to get into the situation we are with weed resistance,” says Basaraba. “It’s good to think about it, but let’s have this conversation now about pathogens and levels of risk.”

The mechanics of fungicide resistance

How does fungicide resistance develop? As with resistant weeds, a naturally occurring mutation allows a particular fungal strain (or isolate) to lose sensitivity to a fungicide, and this mutation is passed on to future generations.

If you think of it as bell curve, says Harding, most strains of a given disease are safely in the middle. “As you go to the highly resistant end of the curve, the number of individuals will drop off. So if you have one individual in a million that’s resistant but you keep applying the same fungicide to it, over time it becomes the most common strain. We’re just selecting for that oddball genotype.”

What makes this process a bit different from herbicide resistance is that when resistant weeds reproduce, their seeds can hang around for a long time. When fungi reproduce, their offspring often don’t survive long without our help.

“There’s a reason these resistant isolates are rare and it’s a fitness cost,” says Harding, explaining the mutation that allows a disease strain to survive a fungicide may come at the expense of other survival mechanisms. “Once you remove the selection pressure, they don’t survive as well in the environment.”

Which brings us to another difference between herbicide and fungicide resistance: the presence of a host. “With some fungal pathogens, if they don’t have a host they can’t complete their lifecycle,” says Harding, cautioning that this is not true of all diseases. Sclerotinia, for example, produces fungal storage bodies that survive very well in the soil for a long time.

As a general rule though, if there is no host tissue for a resistant fungal pathogen to grow on, it doesn’t survive long in the environment. Resistant weeds have no such requirement — the environment is their host.

“The bad news is there are a lot of fungi that have the ability to create diversity through sexual regeneration and form a ton of clones through asexual regeneration,” Harding says. “The good news is we’re the ones supplying the selection pressure so we have the opportunity to change that.”

The importance of understanding different risks

Basaraba says it’s important for farmers to understand the risk levels associated with their fungicide tools, the diseases themselves and their farming practices.

“You need three worlds to crash together to get fungicide resistance,” he says. “Number one is the fungicide and mode of action (MoA). Some MoAs are more prone to resistance developing, like strobilurins. They’re high risk versus triazoles, which are medium risk.”

“Number two is the disease pathogen itself,” Basaraba says, explaining that some diseases are more prone to developing resistance than others, depending on lifecycle. “Fusarium or sclerotinia are low-risk pathogens because they have only one cycle per year. Ascochyta is polycyclic, so it’s high risk.

“Number three is agronomic risk,” Basaraba says. “What are we doing as farmers to accelerate or decelerate development of resistance? Rotations, for example, or how many times do we apply a fungicide to a crop?” Getting disease under control in pulse crops sometimes takes multiple fungicide applications — a higher-risk agronomic strategy — whereas only one application is used to manage fusarium head blight in wheat, a lower-risk strategy.

While it’s good to know and understand the risk levels associated with disease, fungicide actives and agronomic practice, both Basaraba and Harding stress that low or medium risk doesn’t mean zero risk and vigilance is key.

As Harding points out, growing a crop is a complex biological process involving a lot of other factors that can have an effect on disease expression, the development of fungicide resistance and disease control, including the presence of weeds and volunteers, moisture levels, rainfall, temperature, wind… the list goes on.

Basaraba says that even things like premixed or mixable fungicide products can add to the complexity that farmers need to think about. “Farmers automatically think more MoAs is better for fungicide resistance management,” he says. “I think wait a minute! Some of these multi-mode products aren’t full dose rates.”

Echoing that point, Harding recalls the trend of using split-rate applications to control some diseases, like fungal leaf spots in wheat. The idea was to get some control of leaf disease lower on the plant, then go back in later to protect the flag and head. “It’s not a good practice because you’re applying a non-lethal dose both times,” he says. “Hopefully the message is getting out there that you shouldn’t apply half rates.”

“You have to go back to the basics when it comes to fungicide resistance management,” Basaraba says — good crop rotations, understand fungicide MoAs, timely and proper fungicide application, use full rates, don’t over-apply higher risk MoAs, scout and keep good records.

The power of a test strip

Excellent disease control does not necessarily mean a completely disease-free field. Many highly effective fungicides offer suppression only, so how do you know if your fungicide is working properly or if you have a resistance problem?

The only way to know that for sure is to keep an untreated check in the field you’re worried about. And if that idea throws you into a panic, Basaraba and Harding have some wise, calming words.

“Most diseases stay pretty local,” says Harding, adding that most diseases don’t travel more than 100 metres from their origin point. “The exceptions are things like rust in cereals and late blight in potatoes, which can travel far on the wind. But something like sclerotinia, for example, stays local to the field it’s in and, once bloom period is done, infection isn’t going to get any worse.”

As a government researcher, Harding has been involved in dozens of fungicide trials with untreated check strips and says the fear of catastrophic disease spread from them is truly unwarranted. “If you’re uncomfortable with the risk then fine, don’t do it,” he says. “But — how are you going to know if your fungicide actually performed? It’s a balancing act between risk aversion and wanting to know if your fungicide performed. If that information is valuable to you, then have a test strip.”

Basaraba agrees. “An untreated check is the only way you can benchmark what your fungicide is doing for you.”

He also advises farmers to make diligent efforts to measure the differences between the check and the rest of the field. Don’t just look at it, he says. “Take measurements to find out if it’s working or not,” he says, adding that digital farming tools, such as Climate FieldView, can be excellent helpmates in this area. “We’ve helped farmers to do untreated strips and some of them will do a walk-through to check visual differences. But when you can capture that comparison through digital imagery or harvest comparison, you can understand treated and untreated differences much better.

“And if the fungicide is not working then you have to find out why — start checking things off the list and don’t just automatically jump to product failure.” That list includes things like application timing, technique and dose rate, whether the spray equipment was adequate to the task, what the spray conditions were, crop susceptibility to disease, rotations and more.

“When we follow the principles of good crop management, we really do have the power to stay ahead of fungicide resistance,” Harding says. “But if we ignore it, fungi really do have the capacity to adapt.”

“Have an understanding of what it is and have some good conversations,” Basaraba says. “Make rational, knowledgeable agronomic decisions.”

This article was originally published in the 2020 Disease & Yield Management Guide, a Country Guide Special supplement sponsored by Bayer Crop Science.

The post Stay calm and spray on appeared first on Country Guide.

But there’s a lot more going on than meets the eye in that interchange between plant, charcoal, soil and air, and Prem Pokharel is the man to ask about it.

Pokharel, a PhD student at the University of Alberta, is the recipient of the 2018 WGRF Endowment Fund Scholarship. He’s examining what happens when biochar is added to soil — to plant growth, to nutrient mineralization and to greenhouse gas (GHG) emissions. He’s discovered that these changes are different in the rhizosphere (the root zone) than in bulk soil in the rest of the field.

That distinction is key. People have been using biochar to increase soil’s carbon-storage capacity and reduce GHGs for years. But Pokharel points out that the focus has always been on bulk soil, not the rhizosphere. He aims to close that knowledge gap.

“The rhizosphere is a very dynamic system,” Pokharel says. “It’s a very active zone.” That area around plant roots is where microbial life is influenced by chemicals released from the roots and where, as a result, biological and chemical processes are completely different from what happens in bulk soil.

Pokharel’s research is comprised of four separate studies that take on various aspects of how certain biochars interact with the rhizosphere. He’s completed the first two and has already garnered some interesting results.

Experiments with biochar

Biochar is not quite the same thing as charcoal. Both are produced in a similar way by heating biomass under conditions of little to no oxygen, a process known as pyrolysis. This thermal decomposition results in a black, carbon-rich substance. In biochar, it’s highly absorptive and has a high ion-exchange capacity which charcoal lacks.

Not all biochars are the same — it depends on the feedstock. In his work, Pokharel is using biochars created from manure pellets and from willow chips, which are both readily available in Western Canada.

For the first of his four studies, Pokharel used specially designed rhizoboxes — boxes with rhizosphere and bulk soil compartments — in which he grew wheat in a greenhouse. He had five treatments: unprocessed wood chips and manure pellets, biochars from each and an untreated check. Pokharel measured plant production, biomass and CO2 emissions from both the rhizosphere and bulk soils.

The results were mixed for greenhouse gas. “Using a biochar soil conditioner does not always give a positive result in reducing GHGs,” Pokharel says. In one experiment, the manure biochar did not have any effect on CO2 in bulk soil but did reduce it in the rhizosphere. However, results showed that the addition of biochar from either source did reduce CO2 emissions overall.

“I was also looking at the crop productivity, specifically wheat biomass, and the result was different,” he says. “The manure biochar increased total plant biomass and grain yield, while the wood chip biochar reduced both those things.”

The second study used the same setup, but this time Pokharel looked at the effect of biochar on nitrogen mineralization in both the rhizosphere and bulk soil.

“On cropland, we’re mostly concerned with nitrous oxide,” he says. (According to Agriculture and Agri-Food Canada, about 10 per cent of Canada’s GHG emissions come from crop and livestock production, with the two biggest emitters being methane from livestock and nitrous oxide from cropland.)

“Biochar’s role in decreasing nitrous oxide emissions from soil depends mainly on the rate of nitrogen mineralization and its subsequent effect on the denitrification process,” Pokharel explains. How fast N mineralizes depends on the microbial environment. Specifically, it depends on what microbes are present and how plentiful they are. He is looking at the bulk and rhizosphere soils from the first study to see what if any changes the biochars make to the microbial communities. He’s still analyzing the data.

Taking it to the field

The next two experiments will move from the greenhouse to the field. One will look at how biochar amendments affect nutrient leaching and nitrogen recovery by crops, and the other will examine the ideal application rates for biochar and chemical fertilizer used together to get the best crop results while reducing GHGs.

Pokharel has a long way to go with his research, but he’s already uncovered differences between how biochar affects biogeochemical processes — in other words, how biochar influences how things like CO2 and N2O cycle through earth, air and plant, and how that cycle is different in the rhizosphere compared to those same processes in bulk soils.

“What I am trying to see is the mechanism of how biochar affects the rhizosphere,” he says. “It’s important information in understanding the process around the root zone.”

There is real power in the rhizosphere that he hopes can be harnessed through proper use of biochar.

– By Clare Stanfield for WGRF

The post Harnessing the power of the rhizosphere appeared first on Country Guide.

Agronomists have been beating the drum of crop diversity for years and farmers understand that tight rotations of any crop lead to increased disease, weed and insect pressure, and eventually to reduced yield and quality.

But it certainly is difficult to lengthen canola rotations when the crop is bringing in the bucks and you’ve got bills to pay. It’s one reason why, even as the incidence and severity of diseases rise, many farmers still plant canola on the same field every second year. They know it may bite them in future, but the income is needed now.

That dilemma between short-term gain and long-term pain is something Danny Le Roy hopes to ease in the future. An associate professor in the department of economics at the University of Lethbridge, Le Roy is working with U of L bio-economist Elwin Smith and colleagues from the Universities of Alberta and Manitoba on a five-year, WGRF-funded research project aimed at determining the economic value of diversified cropping systems. He wants to put a dollar figure on the tradeoffs between short- and longer-rotation plans. “The reality is that with the spread of root rots, clubroot, blackleg and more, farmers are struggling with crop decisions,” Le Roy says. “That’s part of the rationale for this research. Instead of just relying on a gut feeling, is it possible to put some numbers to it?”

Smoothing the peaks and valleys

Maybe one place to start is to think about the sources of profit. You sell a crop, you get a return, and whether it’s a high or low return depends on markets and the quality of what you have to sell — that’s pretty straightforward. But productivity also influences profit: the more productive the land, the higher the yield and grade, the higher (presumably) the return. You can’t affect markets, but you can affect productivity.

“Up to this point, land has been intensively used,” Le Roy says, referring to the short-rotation patterns typical of Prairie agriculture. “With canola, for example, the tradeoff for it being the money-maker is that canola pests reduce the productivity of that land. If you have a longer rotation, you might have a lower return, but the variability of that return may be lower.”

In other words, what you lose in a spectacular return every few years, you gain in making smaller, but steadier, more reliable returns over time. It’s kind of like the stock market — there are dips and valleys month-to-month and year-to-year, but the overall trend is upward.

Three soil regions

To find out the profit potential of long rotations and fully diversified cropping systems, Le Roy and his colleagues are gathering data from three distinct agronomic regions in Western Canada: the black soil zone of southern Manitoba, where corn and soy crop systems are dominant; black and grey soil zone areas of Alberta and Saskatchewan, where canola and cereals are ubiquitous; and the brown and dark brown soil zones of southern Alberta and Saskatchewan, where pulses reign supreme.

Both short, less diversified rotations and longer, more diversified rotations are included in the study, and data points will be collected by researchers and agronomists from field projects they are already working on. “All the information we need has been collected for years, but it needs to be reorganized,” says Le Roy.

The main goal is to develop a solid framework that farmers can use to help make cropping decisions more easily, perhaps more aware of the risks associated with various choices.

“Margins are very thin,” Le Roy says. “It’s a very competitive industry. A small difference here or there may make the difference between making a mortgage payment and getting foreclosed, and growers need to protect that margin. So if canola doesn’t make the margin you’re used to, a tool like this will help you make some decisions — ‘given what I’m putting in, what’s the best course of action?’”

Specifically, the framework will be a way to quantify the economic tradeoffs between the profit potential of short-rotation crop plans and the long-term benefits of diversification. “I don’t know at this point if the work we’re doing will lead to a commercializable spreadsheet — that would be the dream,” says Le Roy. “The point is to help real people in the real world.”

“The problem motivating this study is timeless,” Le Roy says, adding that the alarm bells ringing now — increased pest severity, resistance and pressure on Western Canada’s major crops — create a sense of urgency. “I don’t know all the answers, but I can help frame the question,” he says.

“The importance of this research is to quantify some things that are becoming increasingly important — this is truly agronomically driven work,” he says. “I would like farmers to know there are means being developed that will help them evaluate the choices they make in the spring.”

This project is funded by WGRF plus these funding partners:

• Alberta Pulse Growers Commission (APG)
• Alberta Wheat Commission (AWC)
• Brewing and Malting Barley Research Institute (BMBRI)
• Manitoba Pulse & Soybean Growers (MPSG)
• Prairie Oat Growers Association (POGA)
• Saskatchewan Wheat Development Commission (SWDC)

The post Putting a value on crop diversity appeared first on Country Guide.

Back then, researchers identified a handful of clubroot pathotypes, mostly minor, and one major one that was responsible for most infections and yield loss in Western Canada. Plant breeders focused on that and introduced the first clubroot-resistant (CR) canola varieties in 2009.

They worked for a while, but then something changed. “In 2014, we started seeing new pathotypes coming out of Alberta,” says Gary Peng, a research scientist with Agriculture and Agri-Food Canada (AAFC) in Saskatoon. “Just in a few fields, but we had a strong sense of resistance breaking down.

“We do have an arsenal of R (resistance) genes, but they are still limited in diversity, especially in terms of resistance mechanisms,” Peng says. “And now we have a total of 17 pathotypes identified in Canada. So the question is, do we have all the R genes against those patho­types, and what’s the best strategy to deploy our R genes for optimum durability and efficacy?”

With funding from WGRF and SaskCanola, Peng and his team set out to answer those questions. And what they found offers new hope for canola producers across the Prairies.

A happy surprise

Used on their own, none of the CR genes currently in the arsenal can be effective against all 17 pathotypes, so Peng was interested in learning how a multi-gene approach would work. Would having more than one CR gene in a cultivar provide more robust disease resistance? Would that resistance last longer?

To find out, canola lines with various combinations of multiple CR genes were tested under simulated, intensive growing conditions against pathotype 5X — one of the newly reported pathotypes that is virulent on all old resistant canola cultivars. The possibilities presented by one particular double-gene combo looked promising.

Nutrien Ag Solutions, a collaborator on this project, bred hybrid canola lines carrying one R gene from chromosome A3 and one from A8. “We wanted to use a commercial breeding process so that anyone could use the approach in their program,” Peng says.

He found that canola lines with these two particular CR genes showed highly effective resistance to the handful of old clubroot pathotypes and partial resistance to pathotype 5X. Peng then wanted to find out if this resistance would also be durable.

“We repeated the plant’s exposure to the patho­type,” he says, explaining that this is done by collecting the clubroot galls from canola roots, drying them, grinding them up, then reintroducing that inoculum to the growth medium before growing the canola in it.

“If you do that with single-gene resistance, it breaks down very fast,” Peng says.

“Our hypothesis was that, even with the two CR genes, the resistance wouldn’t last. But to our surprise, it lasted pretty well at over five generations of exposure,” he says. “And we also saw a reduced level of inoculum in the soil over time.”

Investigating that aspect a bit further, Peng found that these stacked-gene canola lines developed slightly fewer galls over each generation of exposure, and that the galls themselves got smaller over time as well.

Ultimately, Peng says, that meant a smaller amount of pathogen inoculum was returned to the growth medium in each canola generation. That, in turn, resulted in consistent resistance performance from the plant.

Lessons and cautions

“From what I know, this is the first time anyone has looked at the multi-genetic route for clubroot resistance,” Peng says, adding that it is still a relatively new disease of canola and that there is still a lot to learn about the clubroot pathogen itself, as well as resistance mechanisms.

“We may have only two or three R genes to choose from at this time, and pathotypes can have different modes of action. The new ones avoid mechanisms of resistance by the R genes.”

Peng is also quick to point out that, even with two CR genes present in a canola variety, the efficacy and durability of resistance depends a lot on inoculum levels in the soil. “If levels are high, resistance is more vulnerable; if low, it’s more durable, especially for varieties with stacked CR genes.”

Peng says that with a two-year break between canola crops, 90 per cent of clubroot inoculum can die off in soils. It sounds like a lot, but it’s all relative.

“Ten million spores per gram of soil reduced by 90 per cent is still one million spores,” Peng laughs. “But there is still benefit to bringing inoculum levels down in all cases — even in severely infested fields. By bringing that inoculum level down, you allow even the resistant variety to perform better.”

Peng has two conclusions from this study to offer growers:

“One, the double gene will work effectively on older pathotypes and give you moderate, durable resistance against the new pathotype 5X. Two, reducing the amount of inoculum in the soil is good for resistance performance and durability.”

So what now? “I hope to move on to the next stage and look at the new pathotype 3A, 3B and 3D to ensure the resistance performance of a double-gene hybrid.”

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It’s the word “hypothesis” that grabs you. What could be theoretical about cover crops? Some farmers have been using them for decades to help build soil, reduce erosion, graze animals and more. The practice is common in Ontario and Quebec, as well as in the Northern Great Plains region of the U.S. What’s not to know?

Well, when it comes to the Canadian Prairies, quite a bit, says Lawley, an assistant professor in the department of plant science at the University of Manitoba. “Our prairie environment is much more variable and more prone to extremes compared to other areas where cover crops are regularly used.”

Lawley says the thinking behind cover crops on the Prairies has shifted since the time they were considered only for green fallow. “The reasons why we might want to add cover crops are very diverse — soil health, reducing erosion, extending grazing, reducing inputs — so there is now a very diverse range of goals.”

“And that’s why I put the word ‘hypothesis’ in there — because farmers are hearing about cover crops everywhere, but here in this environment, we don’t have a lot of data to show how they actually work.” So with funding from Western Grains Research Foundation, Lawley is leading a team of scientists and graduate students for a new five-year project that aims to find some answers.

The experiment

To generate this data, Lawley has set up a large-plot crop rotation experiment at four sites across the Prairies (Carman, Man.; Lethbridge, Alta.; Saskatoon and Redvers in Saskatchewan) representing a range of soil types and moisture conditions.

There are two main treatments at each site — a four-year annual crop rotation that includes cover crops and the same rotation without cover crops. Third and fourth treatments will act as checks and reflect typical farming practice — a two-year short wheat-canola rotation and a four-year planting of alfalfa or alfalfa-grass mix).

For the first two treatments, cash and cover crops were chosen to reflect regional practices, with wheat and canola at every site, plus a second cereal crop and a legume suited to each location (soybeans in Manitoba and pea in Alberta and Saskatchewan, for example). Cover crops include legumes (like clover), brassicas (such as radish) and grasses (fall rye, for example). All sites will use direct seeding and minimum till, although the Saskatoon site includes one high-disturbance crop (potatoes) for comparison.

“In some ways it’s very simple — we’re comparing two rotations, one with and one without cover crops,” Lawley says. What’s not so simple is that the rotations are fully phased at each site. This means that all crops will be present in all years of the study, thereby removing weather as a factor in the results.

Lawley and her team believe this work will help to definitively show if cover crops can be reliably grown on the Prairies in the first place and if so, their effect on subsequent crops in terms of yield, nutrient availability, input costs, pest control and soil health. “We’re going to be doing an economic analysis and look at the impact on crop production and the soil,” she says. “What’s the benefit of that living root? We’re going to try to put some numbers to that.”

The experiment also offers a golden opportunity to study the effect of cover crops on nitrogen cycling. Nitrogen needs to be available in the soil when the crops need to use it, and researchers want to know if cover crops help or hinder that process.

The study will also look at the effect of cover crops on greenhouse gas emissions. “We want to know if storing nitrogen in cover crop biomass — living or dead — impacts nitrogen loss in the early spring, which is when most N2O emissions are generated,” Lawley says.

Watch this space

“In some ways, we already know we can do this,” Lawley says, explaining that early adopters of cover crops have shown it can work on their farms. “But others are still wondering if it’s worth their time to grow cover crops, so we’re doing this work for them, and also to produce information for agronomists, who get asked questions about cover crops all the time, and need local research to refer to.”

The team has just wrapped up its second field season, so it’s an exciting time for the data crunchers. “In the first year we got baseline samples,” says Lawley. “We’re at the point now where grad students are coming on board to do the intensive sampling and getting all our measurements.”

And farmers don’t have to wait until 2022 to find out what Lawley and her team are learning along the way — check out #PrairieCoverCrops. “Social media is a real enabler of cover crops and soil health information for farmers,” Lawley says. “It’s key for knowledge transfer and for researchers to know what questions farmers are asking. People with good ideas could be so isolated before social media — it’s been a game-changer.”

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Agricultural research, for instance — just gets done. New varieties come out regularly, new insights into pest management or cropping systems are introduced consistently.

And while farmers are certainly aware of organizations which sustain agricultural research in Canada, such as the Western Grain Research Foundation, it might be surprising for many to discover just how much effort, thought, planning and focus are required to keep such an organization responsive, nimble, forward-thinking and above all, relevant to farmers’ needs.

Since its inception in 1981, WGRF has had a hand in the development of hundreds of wheat and barley varieties, not to mention other grains, oilseeds and pulses, and in related crop production research. The sheer volume is impressive: over $183 million in breeding and crop research, more than 600 research projects funded, more than 280 wheat and barley varieties developed for western Canadian farmers.

The transition of WCD (Western Canadian Deduction) check-off dollars from WGRF to provincial commissions had some wondering what it would mean for continued WGRF-funded research like this. Executive director Garth Patterson is here to tell you it’s all good.

Better than good, in fact. With a new strategic plan, a newly focused vision and mission (see at bottom), WGRF is ready to embark on the next 40 years funding vital crop and agronomic research to benefit western Canadian growers.

“For farmers, we’re the only organization that’s western Canadian and focused on cropping systems as one of our priority research areas,” says Patterson. “We’re going to be here to fund research over the long term and our board is focused on having a sustainable fund to support that vision.”

Making WCD work for all

The WCD transition was just the latest in a long line of one-time or transitional funding arrangements for the WGRF. “This was planned,” says Patterson. “This all started back in 2012 when the Canadian Wheat Board was disbanded and time was needed to make arrangements.”

In a nutshell, when the CWB’s single-desk system was eliminated in 2012, the Western Canadian Deduction (WCD) was created to ensure wheat and barley check-off dollars would continue to be collected and used for variety development. It was designed to be temporary, a five-year program that would give provincial grain commissions enough time to get processes and agreements in place to take over the responsibility for funding wheat and barley variety development. “That transition of these check-offs occurred in August 2017, seamlessly,” Patterson says.

WGRF began investing check-off dollars in 1995 to establish core wheat and barley research agreements with the Universities of Alberta, Saskatchewan and Manitoba as well as Agriculture and Agri-Food Canada. After the transition, everyone wanted to see these agreements continue.

“We started working with the commissions about four years ago,” Patterson says. “Step one was for us to renew the core wheat and barley research agreements. We did that in 2015 and they’ll start expiring at the end of 2019 through to March of 2020. The next step was working with the commissions to get everything in place to take over those research agreements, and we’ll continue to work closely with them going forward.”

Ushering in a new era

With the WCD transition behind them, WGRF has a renewed focus on funding commitments in Western Canada. A new vision, mission and strategic plan and research priorities were rolled out in April of this year. “More a tweak rather than a change,” Patterson says. “We’re still very much focused on western Canadian grain farmers and their profitability.

“We have an increased emphasis on use of the Endowment Fund, and have confirmed our commitment to maintain it as a long-term fund for research, and we’ve clarified our research priorities,” he says.

Terry Young, a farmer from Lacombe, Alta., and current chair of WGRF’s board of directors, is excited about those priorities. “Ours is a defined focus on what’s going to help the farmer,” he says, explaining that WGRF has identified variety development and crop production as the two priority research areas.

Those priorities will be applied to research on 15 crops in all: five core crops (wheat, barley, canola, lentil and pea) and 10 intermediate crops (winter cereals, oats, corn, chickpea, fababean, flax, mustard, sunflower and canary seed). Both single-crop and whole-farm integrated multi-crop studies are eligible for funding.

“We have to do research on these intermediate crops because, in the end, we still are an exporting nation and if something takes off with one of those crops, we need to be ready,” Young says.

He’s also enthusiastic about an increased focus on technology and knowledge transfer, a stated goal of the new strategic plan. “We need to make sure the research out there doesn’t sit on the shelf, that it gets to farmers,” Young says. “Extension is very important to us.”

Both he and Patterson point to WGRF’s support of Field Heroes.ca (which promotes the economic impact of beneficial insects and insecticide management techniques to protect them) and Canadiangronomist.ca (which translates “science-speak” into accessible agronomic information) as important tech and knowledge transfer initiatives.

The power of the Endowment Fund

WGRF has worked very diligently to build the Endowment Fund into a sustainable funding source for decades to come. “We can sustain about $6 million per year in research funding,” Patterson says. In fact, funding commitments from the Endowment Fund currently total $48 million, which represents 34 per cent of the fund — the future looks secure indeed.

And don’t forget that much of what WGRF puts into a project can be used to leverage dollars from other sources, such as the Canadian Agricultural Partnership (CAP), which has replaced the federal government’s Growing Forward 2 program. In 2018, WGRF partnered with CAP, participating in five of its agri-science research clusters, and leading the Integrated Crop Agronomy Cluster. Investment in CAP totals more than $6.4 million and supports 44 research projects in integrated crop agronomy, wheat, barley, organic and diverse field crops.

The Endowment Fund also supports a scholarship program for graduate-level agricultural researchers at the Universities of Alberta, Saskatchewan and Manitoba. “It’s part of building our agricultural research capacity for the future,” Patterson says, adding this is important to WGRF.

So important that five years ago, WGRF commissioned a study into the state of agronomic research capacity in Western Canada. It revealed major gaps, existing and impending, in the region’s publicly funded network for agronomy research — both in terms of a lack of people and a decline in facilities and equipment.

“The board has approved $28 million to enhance public research capacity,” Patterson says. “Phase one targets agronomy research capacity at the Universities of Manitoba, Saskatchewan and Alberta, which is near completion. Phase two will focus on infrastructure capacity to support variety development and crop production research.”

WGRF began when 12 farm organizations saw a one-time opportunity to create a research organization that was farmer-centred. The world is not what it was then, but one thing hasn’t changed: “It’s Prairie-wide, producer-invested and producer-directed research,” says Young. And this will always be WGRF’s main strength.

“I would say we’ve shown over the last 38 years that we’re here for the future with a sustainable fund,” Patterson says. “The western Canadian approach is healthy and alive.”

A renewed focus for WGRF

WGRF has always taken its lead from the grassroots. Insights from members, staff, directors and stakeholders were used to develop WGRF’s new strategic plan, including the new vision and mission statements.

• Vision: Profitable and sustainable western Canadian grain farmers.
• Mission: Producers directing investment in crop research to benefit western Canadian grain farmers.

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The professor of soil science in the College of Agriculture and Bioresources at the University of Saskatchewan is leading the Saskatchewan Soil Information System (SKSIS), a phased research project that aims to know everything there is to know about that province’s soil resource and make that data accessible to farmers.

Phase 1 entailed the development and launch earlier this year of the SKSIS digital platform — a website where all the existing information on Saskatchewan’s soils, collected mainly by government agencies throughout the 20th century, is stored and fully searchable.

Bedard-Haughn says the site is intended to be used by farmers, researchers, agronomists, consultants, students — anyone with an interest in or need for knowledge about soils in a specific region, so that they can understand better what’s happening on the ground — literally.

“Part of what we were hoping to provide is a tool to allow people to understand why a piece of land isn’t producing” she says, adding the site can be used to investigate things such as soil texture, salinity, pH and much more. “So far, it’s going really well,” she says. “The feedback we’ve had has been really positive.”

While SKSIS-1 has successfully gathered the fragmented historical soil record into one place, Bedard-Haughn isn’t done. With funding from WGRF, SKSIS-2 aims to build on this framework to refine and expand the information, to find digital avenues for greater flexibility and share-ability, and to make it a true digital farming tool for the modern age.

“There are two main things we want to do,” she says. “The first is to enhance the current information.” To understand this, you need to zoom in on the SKSIS website until you start to see the irregular shapes that form the boundaries of different soil polygons.

“When they did the original soil surveys, they did it quarter section by quarter section,” says Bedard-Haughn. They then looked at which groups of soils commonly occurred in association with each other and then mapped those associations as polygons. This means the polygons are a little clunky by today’s precision agriculture standards for soil information. Sometimes a quarter section might be mapped as a single polygon, which itself might encompass three or more soil types.

To get from the current polygons to a more refined type of mapping that better reflects within-field variability, one big information gap is a lack of high-quality topographical information.

“We’re trying to come up with a method where farmers can input their own information, such as surface maps, soil test results and the like, and get back refined data of their own,” Bedard-Haughn says. “We couldn’t have imagined at the time the polygon maps were developed that precision farming would be at the level it is now.” In other words, knowing everything there is to know about every square metre of soil is information that can actually be used to good effect with today’s precision ag equipment.

One-stop shop

The second main focus of SKSIS-2 is to enhance the way new soil data is shared — “So that researchers and, wherever possible, producers, don’t spend so much time reinventing the wheel,” Bedard-Haughn says. Given how long this land has been farmed, researched and documented, it’s highly likely that someone has literally gone over the ground before and made notes. “Some things don’t change too much over time, like texture, so if another researcher goes to an area five years later and tests again, not knowing that information already exists, it’s a waste of time and resources.”

The trouble is that not all of these records are in one place. By providing a venue to share that information, with the appropriate checks and balances in place to ensure privacy as needed, the soil database gets richer, deeper and more useful.

To be sure, the goal is to document much more than things that stay relatively static. “There’s increasing interest in monitoring things like carbon, for example, to see patterns of change over time as they relate to climate or production,” Bedard-Haughn says. As well, infrastructure and events related to resource extraction, such as boreholes and spills, or natural events, such as fires and floods, all have an impact on soil productivity and can be noted in the SKSIS database to help develop high-resolution maps of soil characteristics so that farmers can better determine why a certain situation exists in their fields, which is the first step toward fixing it.

“I would love for farmers to be able to use this system to gradually improve the data available on their land,” Bedard-Haughn says. “They can bring yield and quality information into it and really understand how this land responds year over year, so precision ag means something.”

To that end, the SKSIS system was built using open-source software, making it fully accessible and useable by anyone. The more robust the data becomes over time, the more useful it is. “I want farmers to better understand the land they’re working, that’s their baseline,” Bedard-Haughn says. “To manage soils effectively, you have to understand them.”

The Western Grains Research Foundation (WGRF) is a farmer-funded and directed non-profit organization investing in agricultural research that benefits producers in Western Canada. For over 30 years the WGRF board has given producers a voice in agricultural research funding decisions. WGRF manages an endowment fund and the wheat and barley variety development check-off funds, investing over $14 million annually into variety development and field crop research. WGRF brings the research spending power of all farmers in Western Canada together, maximizing the returns they see from crop research.

The post The power of knowing your soil appeared first on Country Guide.

And that’s just glyphosate resistance. According to the International Survey of Herbicide Resistant Weeds, Australia has 90 unique resistant weeds — that doesn’t mean 90 weed species, it means 90 unique instances of resistance by site of action. For example, a population of annual ryegrass with seven-way resistance in South Australia is unique from populations of the same weed in the same state with one-way resistance. Canada, by the way, has 67 unique resistant weeds, putting us at No. 3 in the world.

Facing the loss of herbicide and cultural control tools, growers in Australia began to feel their resistance problem has become so severe, the industry simply had to do something different, which helps explain the Harrington Seed Destructor (HSD). Invented by Ray Harrington, a grain farmer from Western Australia, the HSD pulverizes chaff and weed seeds at harvest as they leave the combine.

That it’s a harvest tool is important. Farmers in Australia invented and are increasingly turning to harvest weed seed control (HWSC) to manage resistance. It’s an approach that focuses on reducing or even eliminating weed seed return to the seed bank, and the HSD is one tool in the HWSC toolbox.

But could the HSD work here in Western Canada, with our different cropping systems and weed profiles? That’s what Dr. Breanne Tidemann is aiming to find out.

A field agronomist and weed scientist with Agriculture and Agri-Food Canada in Lacombe, Alta., Tidemann has just embarked on a three-year study, funded in part by WGRF, to test the HSD in Canadian conditions.

Designing a Canadian experiment

“First we did stationary evaluations of the seed destructor,” says Tidemann. This involved mixing five-gallon pails of chaff and weed seeds (noting the seed size, type and number as well as chaff type and volume), firing up the machine in a shop space, feeding the material through and then assessing the level of seed destruction — which was almost always more than 95 per cent.

“Of course that doesn’t account for seeds that get missed by the combine in actual field conditions,” she says, adding that it did provide a baseline of information to compare with field performance.

In 2017, Tidemann and her team identified 20 producer fields in the Lacombe area for testing the HSD. “We were looking for fields with weed problems,” she says. “The weeds didn’t necessarily have to be herbicide resistant, although we know that with the wild oat populations we’re looking at, for example, chances are there is some resistance there.”

Tidemann says they were looking at a fairly typical cross-section of western Canadian weeds, including wild oats, cleavers, volunteer canola, hemp nettle and chickweed.

The first harvest using the HSD was in 2017. In all, three crops and five cropping systems were involved: wheat (straight cut and swathed), canola (straight cut and swathed) and peas (straight cut). Each field site was split into three to four replicates, and each replicate received two randomized treatments. Treated areas were those where the crop was harvested using the HSD, and untreated areas were those where the crop was harvested normally, without the HSD.

Prior to harvest, researchers did weed counts by species in 20 half-square-metre locations across each site. “Our first results in terms of weed control will come from population counts in the spring,” says Tidemann, adding that she doesn’t necessarily expect to see a huge difference between treated and untreated fields in year one, especially with weeds that have substantial seed banks like wild oat, but she is hoping to see fewer weeds in subsequent years. “We’ll go three harvests in a row on these fields to get a good sense of how effective the seed destructor is at keeping weed seeds out of the seed bank.”

Still, the first year has yielded some information about operating the HSD effectively. “The first thing we learned is that air velocity to move the chaff once it’s off the sieves is key to getting it up and over the inlet and up the slope into the destructor,” she says, adding that to get from the combine into the HSD, the chaff stream has to move straight up, go through a U-bend, then down again and then up a slope to get to the mill. “The second thing is that green or tough material doesn’t flow well and should not go into the seed destructor.” (No surprise, given that pathway just described.)

The third thing is that the tow-behind model Tidemann is using for this study is not well suited to Canada. “The hills we have here create an accordion effect, which can cause some damage to the metal pipes and extra maintenance costs.” There are integrated models of the HSD that would work better here, and Australian studies show that both types provide the same level of weed control.

No easy fix

If the Harrington Seed Destructor seems like the final answer to all your weed resistance prayers, Tidemann is here to tell you it’s not. She says that even if her research shows the HSD to be a good fit for Western Canada, the weeds themselves will ensure that it becomes simply another tool, albeit a powerful one, to add to your integrated pest management (IPM) toolbox.

It’s because weeds are nothing if not survivors. The story Tidemann likes to use to illustrate this point is one about barnyard grass that was hand-weeded from rice fields. The visual differences between the weed and the rice allowed for that type of control, but over time the weed slowly changed its physical appearance to look like rice. “It shows that if you’re constantly using one thing to control weeds, they will find a way to defeat it,” she says.

Expanding the IPM toolbox to include HWSC options (such as the seed destructor) along with herbicides and mechanical controls (such as mowing), simply makes for better overall weed management. “If you can hit those weeds at multiple stages in their growth using different control methods, they can’t adapt as fast,” says Tidemann. “I’m hoping that this research will give us a good idea of how a thing like the seed destructor can work here.”

She should have her final results in 2020. “It may turn out to not be the solution for us, but this project is pushing people to think about different ways to manage herbicide-resistant weeds, to think about non-herbicide tools and think outside the box a bit.”

The Western Grains Research Foundation (WGRF) is a farmer-funded and directed non-profit organization investing in agricultural research that benefits producers in Western Canada. For over 30 years the WGRF board has given producers a voice in agricultural research funding decisions. WGRF manages an endowment fund and the wheat and barley variety development check-off funds, investing over $14 million annually into variety development and field crop research. WGRF brings the research spending power of all farmers in Western Canada together, maximizing the returns they see from crop research.

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