Genomics can help open new markets but may be powerless against disease due to complex genetic design
For pulse breeders like Kirsten Bett, there are many things they can do to improve crops for producers, but they can’t protect farmers from themselves.
“Stop growing lentils on lentils, people. That’s why you have an aphanomyces problem, basically,” she said. “This is huge, this is one of the big issues right now, in not just lentils, but also peas.”
Bett runs the dry bean breeding program at the University of Saskatchewan and also works closely with her colleague Bert Vandenberg on lentil development.
Too-short rotations are a big issue not only in pulse crops but also in canola, although the specific disease is different.
Bett said it is common knowledge that pulses should be grown in a four-year rotation with oilseeds and cereals. Ideally, the pulses themselves should be different as well.
Unfortunately, good agronomic practice often takes a back seat to economics.
“I’ve talked to folks and they know damned well you shouldn’t do this, but then they go, ‘yeah, but when you pencil it out, it’s worth the risk,’” Bett said.
Then, producers ask for lentils that can resist aphanomyces root rot, to solve a problem of their own making.
“I know I’m not anybody’s favourite person for saying that, but….”
Producers’ voices are a key facet of lentil improvement for Bett and her colleagues. They continually consult producers on what traits they should pursue to improve Canadian lentils.
The problem with aphanomyces is that there may not be a solution, certainly not an easy one. All existing varieties of lentils appear to have little or no resistance to the disease, and it’s not for lack of looking. Nor is it for lack of producer support.
SaskPulse, funded by producer checkoffs, provided backing for AGILE (Application of Genomic Innovation in the Lentil Economy). With additional money from the Western Grains Research Foundation and the Saskatchewan government, Bett, Vandenberg and colleagues were able to leverage funds from Genome Canada. This touched off complementary projects in the United States and Australia.
“They (SaskPulse) took a leap of faith on the sequencing of the lentil genome when we couldn’t get anyone else internationally to pony up any of the cash,” Bett said.
AGILE started with about 450 different varieties of lentils from around the world, tapping gene banks in the U.S., Canada, and ICARDA (International Center for Agricultural Research in the Dry Areas), including a Syrian gene bank that had been moved to Morocco due to war.
From this initial group, they picked 324 lentil lines that represented the whole set. This included several wild varieties. Then they got to work genotyping, that is, determining the unique genetic makeup of each variety.
With the lentil genome in hand, researchers can now look for markers, genes associated with desired traits such as drought tolerance and yield. This allows them to easily screen out the best crosses from thousands of options without having to grow them out in the field, a technique called marker-assisted breeding.
The AGILE sequencing project was completed in 2018. A follow-up project, EVOLVES (Enhancing the Value of Lentil Variation for Ecosystem Survival), is now underway.
This genomic knowledge opens up possibilities. One of the challenges with lentil development is seeds are easy to move. For example, researchers have seen lentils developed for Saskatchewan show up in Kazahkstan, which has similar growing conditions. Bett said part of the solution is continuous improvement.
“In the absence of the ability to control what seed is being grown in other jurisdictions, the best we can do is basically stay one step ahead or preferably multiple steps ahead.”
Another strategy is to develop the genetic mastery to custom-breed lentils, tailored for specific markets, to command a premium. This is one of the goals of the EVOLVES project.
“Go after the higher value markets. Stop bulk shipping,” Bett said. “Just go after the expensive markets that will pay us a premium for a higher value or a higher quality product that you’re not going to get out of somewhere like Kazakhstan, where they’re still learning.”
Whatever the market strategy, producers still must rely on good rotation practices to protect their ability to grow lentils on the Canadian prairies.
Bett said that of all the varieties sequenced in the AGILE project, only the wild varieties showed some modest resistance to aphanomyces root rot, and it’s a long way from the wild to a cultivated field.
“It’s bad enough when you cross with a line from south Asia to bring in something,” Bett said. “But if you try and cross with a wild species, not only is it probably unadapted, but it’s also got things like it shatters and the seed size is ridiculously small, and all sorts of other characteristics that are undesirable.”
There are no shortcuts in this process. International market demands effectively prohibit the use of genetic engineering for Canadian pulse crops. Bett said this is likely moot since these techniques involve working with just a few genes and disease resistance is governed by many.