Author: cwrc2023dev

Fusarium head blight (FHB) is a fungal disease that infects wheat and other cereal crops. Depending on when infection occurs, FHB can reduce the number of kernels developed or result in Fusarium damaged kernels (FDKs) and contamination with deoxynivalenol (DON). If infection happens later, kernels may not appear damaged, but could still contain DON, which is a health risk for humans and animals.

“The presence of FDKs in harvested grain results not only in a reduction of yield and downgrading, but the infection will also impact functional characteristics of the grain for end users,” explains Kelly Turkington, a research scientist with Agriculture and Agri-Food Canada.

FHB is a difficult problem to manage. “Breeders have made incremental improvements, but the varieties we have available still don’t provide a high level of resistance,” Turkington says. “Fungicides provide suppression at best, and the crop rotations we’re using are not quite long enough to be an effective disease management tool.”

He recommends an integrated approach. “You can’t rely exclusively on one tool, you need a set of tools,” he says. “You need to rotate (not plant wheat on wheat), you need to apply a fungicide at anthesis (flowering), and you need to grow a ‘resistant’ variety.”

Turkington is running two different trials to explore a number of cropping strategies to reduce the impact of FHB. One is looking at crop rotation and residue management.

“We’re hoping to demonstrate the role extending the rotational interval from one year to two, or even three years, can have on disease risk, meaning the amount of infected residue that persists until the next time you grow wheat in that field,” explains Turkington.

Infected residue allows the pathogen to overwinter on the field and can result in spore production and reinfection if a cereal is grown the following year. The idea is to remove some of that highly infectious crop residue to reduce the extent of FHB infection in subsequent years.

The other trial is looking at row spacing, seeding rate, and fungicide timing.

He’s comparing narrow row spacing (7 to 10 inches) and wider row spacing (12 to 14 inches). Traditional thinking, he explains, suggests wider row spacing will lead to more air movement and shorter periods of high relative humidity and leaf wetness, which should discourage FHB. However, wider row spacing may also provide more wind access to infected stubble, which means spores could be more readily carried up onto the head. His theory is that low row spacing likely won’t have an impact on micro-environments, but it might help reduce spore dispersal.

He’s also comparing low and high seeding rates. Lower seeding rates result in more secondary tiller development and a less uniform crop. If you spray a fungicide when the main-stem tillers begin to flower, which is the ideal time, the heads on secondary tillers may not even be out and won’t be protected. Turkington’s theory is that higher seeding rates will result in more uniform crop development, more uniform head emergence, and hopefully better management of FHB when fungicides are applied.

Finally, he’s looking at four different fungicide treatments:

• No spray (as a check)

• Early application (about 4 days after head emergence)

• Later application (about 7 to 10 days later)

• Dual application (early and again later)

Traditionally, fungicide application happens at the beginning of anthesis. “It’s a key time for infection and production of FDKs and DON,” Turkington says. “If you apply a fungicide later, the concern is that it might not have the same impact. Based on research out of the US over the last five or so years, that simply isn’t the case.”

He says you can apply a fungicide later and have very similar, if not better management of FDKs and DON. However, later application may have implications for recommended pre-harvest intervals. Later or dual applications would likely require revisions to fungicide labels.

This Wheat Cluster project received funding from Agriculture and Agri-Food Canada through the AgriScience Program, which is part of the Canadian Agricultural Partnership, a federal, provincial, territorial initiative. This project also received funding from Alberta Wheat Commission, Saskatchewan Wheat Development Commission, Manitoba Crop Alliance, and Western Grains Research Foundation. Turkington is hopeful his research will lead to improved strategies to mitigate FHB in wheat, thus limiting the impact of this issue for producers.

To read the project profile, CLICK HERE.

Robert Graf, a research scientist with Agriculture and Agri-Food Canada, Lethbridge Research and Development Centre, is developing improved Canada Western Red Winter (CWRW) wheat varieties for Western Canada.

Winter wheat acreage is relatively small, he says, so before he proposes a new variety for registration he wants to be sure it will really make an impact for producers. “Having a huge number of varieties is not going to serve anyone if we’re not making improvements,” he explains.

In his new varieties, he’s targeting resistance to the priority-one diseases—rusts (stem, leaf, and stripe), Fusarium head blight (FHB), and common bunt—but he’s also looking to add resistance to the wheat curl mite (which provides protection against wheat streak mosaic virus) and resistance to the Russian wheat aphid (which is a problem in some parts of the US and presented a scare in Western Canada in the late 1980s).

Wheat stem sawfly is another insect pest on his radar. Sawfly has long been an issue in spring wheat, but it hasn’t been a problem in winter wheat in Canada. Graf says there are populations of sawfly in the US that have synchronized their life cycles with winter wheat and have become a major problem as close as Montana, so he’s developing solid-stem varieties that will be inhospitable to sawfly.

His highest agronomic priorities are higher yield and winter survivability. “With climate change, we’re seeing a lot more variability in our extremes,” he says. “Some suggest that, over time, we may not need the level of winter hardiness that we currently strive for, but in the short and medium term, we need to maintain that excellent level of cold tolerance to reduce production risk.”

He’s also working to increase yield by up to 18% over CDC Buteo. He says, “that’s a stretch goal, but we’re definitely going to be able to approach it, and actually exceed it in some areas.”

AAC Network, a milling quality variety that has high protein, will be available this fall. Graf says, “It has the most complete disease resistance package of any winter wheat variety available.”

It also appears to have improved drought tolerance, which Graf says is something he’s going to be watching over the next couple of years. “This variety works in all areas of Western Canada,” he says, “but it seems to be best adapted—where we see the biggest jump in yield over other varieties—for southern Alberta.”

In 2020, he received support for a new, as yet unnamed, variety known as W583. He sees W583 as a potential replacement for Emerson, one of its parents. Ten years ago, Emerson was quite a breakthrough, explains Graf. It was the first variety in Canada rated resistant to FHB, and it had good resistance to the rusts, but that resistance came at somewhat of a cost in terms of yield.

“We’ve been working really hard to maintain that disease resistance and increase yield,” he says. W583 is the first result of these efforts and will be registered with a name this spring.

In 2021, he received support to register W601, which he describes as a “really exciting variety that looks like a breakthrough in yield.” In registration trials, it yielded significantly higher than all the checks and well over 20% more than CDC Buteo in some areas.

Next year he expects to get support for another variety that’s showing yield similar to AAC Wildfire, but has a more complete disease resistance package.

This Wheat Cluster project received funding from Agriculture and Agri-Food Canada through the AgriScience Program, which is part of the Canadian Agricultural Partnership, a federal, provincial, territorial initiative. This project also received funding from Alberta Wheat Commission, Saskatchewan Winter Cereals Development Commission, Western Grains Research Foundation, and Winter Cereals Manitoba.

To read the project profile, CLICK HERE.

Wheat producers face a variety of challenges that impact yield, grade, and farm operations. Richard Cuthbert, a wheat breeder with Agriculture and Agri-Food Canada, Swift Current Research Development Centre, says new wheat varieties can provide solutions to many of those challenges.

He’s trying to develop field-ready varieties of Canada Western Red Spring (CWRS) wheat for producers in the brown and dark brown soil zones (southern Alberta and southwestern Saskatchewan) that will respond to stresses in those regions—typically heat and drought.

“We see more extremes from year to year in terms of climate—moisture may be limited in some years and excessive in others,” he says. “We can’t predict what the environment will be, so we need varieties that can withstand a range of conditions.”

Creating something that adaptable brings significant challenges, explains Cuthbert, “but we’re fortunate to be working with improved genetics that have been bred over decades, maybe even a century, in Canada. We have a pretty good base to work from.”

Among the five priority-one diseases—Fusarium head blight (FHB), leaf rust, stem rust, stripe rust, and common bunt—Cuthbert says FHB and stripe rust are the biggest challenges.

“Stripe rust in particular has become a bigger concern in the Western Prairies in recent years,” he explains. “There seem to be new races that are able to withstand higher temperatures and may overwinter in Canada . . . That could be due to changing climates, but that’s just speculation. We know that stripe rust is persisting and is more prevalent.”

To have a fighting chance against rust, Cuthbert says farmers can’t rely on chemical controls alone. “We need genetics that will reduce farmers’ reliance on chemical controls. The fewer controls you need to use the better, from a profitability standpoint and from an environmental standpoint.”

He recently released a couple of new varieties that he’s very optimistic about. AAC Starbuck and AAC Wheatland are both semi-dwarf CWRS varieties with excellent grain yield, high protein, good straw strength, and tolerance to orange wheat blossom midge. AAC Starbuck also provides fewer FHB symptoms and lower accumulation of deoxynivalenol (DON), the mycotoxin produced by Fusarium species.

 “They’re performing very well and the feedback is quite positive, so we’re optimistic for their launch this spring,” he says.

AAC Hockley is another new variety that came out last year. It’s not midge-resistant, but Cuthbert says it has an excellent disease resistance package, including improved FHB resistance.

Most breeding programs focus on resistance to the priority-one diseases, which is required for registration, but Cuthbert says his program has been maintaining resistance to loose smut as well.

“Doing the minimum is a good way to get in trouble, so we try to go above and beyond, especially with disease resistance,” he says. “Loose smut hasn’t been a concern in recent years, so it was removed from the breeding requirements, but we try to maintain it in our varieties so we don’t inadvertently introduce a susceptibility to the disease.”

Cuthbert’s new varieties are providing farmers with higher yields, assured performance, and a comprehensive disease resistance package. He projects that, by the end of the project, these new varieties could generate $100,000,000 in additional annual farm revenue.

This Wheat Cluster project received funding from Agriculture and Agri-Food Canada through the AgriScience Program, which is part of the Canadian Agricultural Partnership, a federal, provincial, territorial initiative. This project also received funding from Alberta Wheat Commission, Saskatchewan Wheat Development Commission, Manitoba Crop Alliance, and Western Grains Research Foundation.

For the project profile, CLICK HERE.