Flax acres have started to rebound over the past few years, with Saskatchewan still accounting for most of the flax grown on the Prairies. In order to entice more growers to flax, however, yields will need to increase.
Average flax yields have hovered around 22 bu./ac. for many years, and although growers in some areas of Western Canada have achieved double that, it’s not always consistent, so improving yield continues to be a key focus of agronomy research.
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Many factors contribute to yield, and researchers in Saskatchewan and Manitoba have been working on a three-year project to update agronomic practices.
“We’re focusing on the agronomy,” says Rachel Evans, extension agronomist at the Flax Council of Canada. “As varieties and equipment change, and as our climate changes, there is a need to go back and re-look at what we’re recommending.”
At the end of this year’s season, researchers will have 12 site years of data about seeding rates, seeding dates, row spacing, weed management, fungicide use and fertilizer rates, and some of these results are already creating interest.
Researchers started with what’s called an ideal plot, i.e. a combination of all of the best management practices to date as a control plot in four separate trials. One trial then looked at fertilizers and seed treatments, another at herbicides and fungicides, a third at seeding rates, dates, depth and row spacing, and the trial at crop rotation seeding into five different crop stubbles.
The trials, says Evans, are pointing out some “low hanging fruit, one of them being fertilizing appropriately based on what your background soil fertility levels are.”
Fertilize what you need
Unlike some fertility trials where researchers evaluate standard rates such as 25, 50, 100 or 150 lbs./ac. of nitrogen (N), the flax trial started with soil tests and then topped up required fertilizer to achieve a 45 bu./ac. yield.
Plots with high background nitrogen (N) didn’t see a significant yield response to added nitrogen rate, which made sense as the soil already had enough to produce that 45-bushel yield, says Evans. “But when we have low N, we see a significant response to fertilizer rate.”
It’s a valuable learning, not just for agronomics, but economics too, Evans says. “Flax is a crop that does respond, but knowing where you’re starting from is important.”
Researchers seeded flax on the ideal seeding date of May 15, and also a week earlier, one week later and two weeks later. The latest seeding date showed a yield penalty.
“We have a lot of flexibility with flax seeding dates up until the May long weekend. After that we start to see yields drop off,” says Evans.
Flax has fairly good frost tolerance, she adds, and it is a long-season crop, requiring anywhere from 95 to 125 days to mature, so seeding early can be a strategy to help growers combine early.
Says Evans, “Seeding before the May long weekend is the major message.”
Three weed management trials currently underway at the University of Saskatchewan are looking at herbicide options, integrated weed management strategies, and rotations, although results are still preliminary and analysis is currently underway.
In a herbicide screening trial, some new and existing products which are not yet registered for flax are being evaluated. Some are definitely showing potential, so there may be more herbicide options for flax growers coming down the pipe, says associate professor Dr. Chris Willenborg, who is heading up the weed management trials.
Another trial looking at integrated weed management strategies is finding some good results when using a higher seeding rate of 800 seeds per square metre combined with a taller cultivar and early seeding dates.
“Seeding at 800 seeds per square metre gives a plant stand around 450 plants per square metre which we believe is ideal,” says Willenborg. “We also found that the taller flax cultivar tended to give better plant populations, especially when seeded early, and this contributed to improved competitive ability.”
The higher seeding rate, tall cultivar and early seeding combination had no negative influence on wild oat seed production, but it did reduce wild oat biomass and increase crop biomass in the trials.
“A lot of flax growers probably aren’t seeding at that high rate,” Willenborg says. “Our data would suggest they should be, and also that flax cultivar is important when it comes to competing, particularly, with Group 1-resistant wild oats, which is a big problem in flax.”
The jury, though, is still out on another trial evaluating the best rotation to set up a four-year flax rotation from a weed management perspective.
Flax breeding and research into pasmo management as well as fungicide timing and drought resistance are being funded through the Growing Forward 2 Agri-Innovation Program.
Although the breeding program at Agriculture and Agri-Food Canada’s (AAFC) Morden Research and Development Centre closed last year, the flax pathology program remains and is focusing on developing genetic resistance to pasmo.
In the past, the program has successfully identified and made resistance genes available to plant breeding programs for other flax diseases — rust, fusarium wilt and powdery mildew — which have been bred into flax cultivars for growers.
Scientists are working to do the same for pasmo, and have already identified some promising genetic material, although pasmo presents more of a challenge than other flax diseases because it has multiple races, so multiple genes are required to provide effective resistance to the pathogen.
“We have screened around 3,000 accessions of flax from around the world and identified sources of genetic resistance to specific races of pasmo, so for example one gene may resist isolates one, two and six, but not five and seven, while another may resist five and seven but not nine. The challenge is to pyramid those genes to get better field resistance and make that material available to the breeding program,” says Dr. Khalid Rashid, the research scientist leading the flax pathology program at Morden.
Researchers also need to combine the pasmo resistance with the key agronomic requirements such as quality and yield, Rashid says, “so it’s complicated to combine all those traits that the breeders want in a cultivar before we can release it to the grower.”
In 2006, researchers at AAFC, Morden began a 10-year fungicide trial with 15 different fungicides. The trial has identified opportunities to reduce the pasmo disease incidence and severity by up to 70 per cent. Increases in yield varied from year to year depending on the severity of the pasmo, but fungicide-treated plots yielded in a range of 70 up to 350 per cent more than the non-treated plots.
The most effective fungicides in a descending order of effectiveness were: Priaxor, Xemium, Headline, Quadris, Fox325-Sc, Acapela, Prosaro and Vertisan.
Another three-year study headed by Cecil Vera at AAFC’s Saskatoon Research and Development Centre, in collaboration with Dr. Randy Kutcher of the University of Saskatchewan’s Crop Development Centre (CDC), has been looking at the timing of fungicides to help control pasmo in flax. The study was conducted at sites in Saskatchewan and Alberta and used three different fungicides — Headline EC, Priaxor and Xemium. All fungicides reduced disease severity, but Priaxor was often the most effective. In terms of timing, application at the early flower stage was less effective than at mid-flower, and there was no difference in disease severity when fungicide was applied at the mid-flower stage or when a dual application was made at early and mid-flower stages.
When it came to yield, Priaxor and Headline had a similar benefit for yield, increasing it on average by 23 per cent more over the control and four per cent over Xemium. Both Priaxor and the dual fungicide application delayed maturity by five days, however, which could affect seed quality.
Researchers suspect the delay in maturity could be due to the effectiveness of the fungicide treatment because pasmo often results in premature ripening and earlier harvests. Seeding flax earlier might help offset delayed maturity.
Yield was increased by over 20 per cent with a single fungicide application (average of all three fungicides) at the mid-flower stage. There was no yield benefit to two applications (one at early flower and one at mid-flower) compared to the single application at mid-flower.
“I think two applications would rarely, if ever, be economically beneficial, based on current yields and prices for the fungicide and flax,” Kutcher says.
It’s still tricky to time the application of a fungicide for pasmo because the disease can often appear late in the season when it’s too late to spray. Researchers suggest farmers make that decision based on environmental conditions, their previous experience with pasmo, flax frequency in the rotation, and proximity to adjacent flax stubble.
More drought tolerance
Flax is a shallow-rooted crop and can be particularly susceptible to drought, with roots unable to reach and access moisture further down in the soil, but to date little research has been done into drought tolerance in flax.
Dr. Raju Datla, a research scientist at the National Research Council of Canada, is working with Helen Booker at the CDC to address this unmet critical need and identify flax genotypes that can better withstand drought conditions. By applying physiological and genomics tools, and looking at the genomic sequence of flax, his team has identified potential candidate genes that appear to be specifically expressed only under drought conditions.
Greenhouse research has also revealed that some tolerant flax genotypes appear to conserve moisture better during drought periods by reducing the amount of water transpired through the stomata on their leaves, which also collect carbon dioxide for photosynthesis. “We think the guard cells that regulate the stomata pores are responding to signals that there is a threat of drought coming, and the plant has to change its program in such a way that it loses less water and doesn’t expend all the moisture it has,” says Datla, who adds the next step is to incorporate the genetic components conferring drought tolerance into cultivars for field assessment and to develop improved Canadian flax cultivars.
There used to be three flax breeding programs in Western Canada, including AAFC’s program at the Morden (Manitoba) Research and Development Centre, and the private Crop Production Services (formerly Viterra) program, but only one now remains at the University of Saskatchewan’s Crop Development Centre.
Dr. Helen Booker is the flax breeder at the CDC, where priorities for breeding obviously include increasing yield, but also a number of other agronomic traits important to growers, such as timely maturity and increasing ease of harvest.
“We are looking for things that are associated with better harvestability, like a more determinate flowering or growth habit so the plant shuts down at the end of the season and doesn’t keep flowering and diverting resources away from the maturing capsules,” says Booker. “We’re also looking at things like stem dry down, so the stems will be brown and dry at the same time the capsules are mature, rather than having a green stem.”
The CDC program has released several new varieties of flax over the past few years, most recently CDC Dorado, a yellow seed variety that has 64 per cent ALA (Omega-3 rich, alpha-linoleic acid) content, the highest ever ALA content in a CDC cultivar (it should be commercially available soon through SeedNet in Alberta).
Another new CDC line — FP2513 — has just received support for registration this year. This brown flax seed line has 59 per cent ALA content and a yield potential 12 per cent higher than CDC Bethune, the most commonly grown flax variety, and up to 17 per cent higher in black and grey soil zones.
The CDC breeding program is hoping to secure the germplasm and breeding material from the other defunct flax breeding programs, says Booker. “We built on each other’s successes within breeding programs, so getting access to the AAFC and the CPS material would be good to incorporate into the pipeline, so we can keep that good material in Canada.”
The future for flax
When GM traces of Triffid were found in export shipments to the European Union (EU) in 2009, the flax industry in Canada all but collapsed. Acres went down and other countries like Russia and Kazakhstan grew more to serve that market.
Still, China has grown significantly over the past four or five years, and all indications are that it will continue to be a strong market for Canadian flax.
The U.S. is another major flax grower and thanks to a very large crop in 2015, it’s had large carryover stocks, which has depressed Canadian exports into that market over the past two years. With drought in the northern U.S. this year, however, there may be some opportunities for Canadian flax exports to increase.
“I believe we are in the process of a rebound in flax markets and prices this year, partly because of the dry weather in Western Canada and the U.S.,” says Chuck Penner of LeftField Commodity Research in Winnipeg. “What’s unknown is the potential for growth in the domestic market, both for human use and Omega-3 animal feed, because no one has ever measured how much flax is going into those markets in Canada.”
What is known is that demand for flax as a functional food continues to grow worldwide, and Manitoba and Saskatchewan have companies in that race.
“We can see great potential for flax,” says Evans. “We have a growing middle class in many countries of the world and that growing middle class suffers from all the same middle class problems that we have in North America with obesity, and hypertension and other cardiovascular diseases. If we can continue to work and develop markets in those areas, I think that will be an advantage to us down the line.”