Perennial cereal rye 2.0

After setbacks with an earlier program, Lethbridge researchers are making progress in developing a dual-purpose grain and forage rye

It sounds ideal like the ideal crop. It produces grain every year, has no annual seed and planting costs, provides excellent weed control and you can also use it for forage. Too good to be true? Maybe not.

Efforts to develop perennial wheat continue their slow pace with commercialization pegged at around 15 years from now. But researchers at Agriculture and Agri-Food Canada’s Lethbridge Research Centre say they are much closer with perennial rye. You could call it “perennial cereal rye 2.0.”

“I’m very confident in the genomic tools we have available and the network we have to work with,” says AAFC’s Raja Ragupathy.

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“I want to be very cautiously optimistic but I’m also very excited at the challenge. I’m pleased to say within the next eight to nine years we could have a commercial variety.”

Ragupathy recently took over cereal research from Jamie Larsen, who now works as a dry bean breeder for AAFC in Harrow, Ont.

“Perennial cereal rye is the closest thing to a productive perennial grain that we have in the world. Right now it’s probably the closest perennial grain that a farmer can grow and be relatively content with what they have,” Larsen says.

“Even perennial wheat — and I would argue even kernza (an intermediate wheatgrass similar to soft wheat) — is pretty challenging. They are just not productive enough yet, although kernza is getting close.”

Perennials use sunlight, moisture and fertilizer more efficiently than annual crops, creating both production and environmental benefits. Crossing them with an annual plant can create new opportunities for both grain and cereal crops.

“With perennial cereal rye you have all the benefits of a perennial,” Larsen says. “It provides constant cover competition with weeds’ access to moisture and sunlight. It greens up early and then stays productive later into the fall so you can have your livestock on it early in the year and then later in the year.”

Perennials also have deep roots which take nutrients from deeper in the soil and could potentially increase soil carbon. Rye is also known for its large root system, making it a good candidate to maintain this benefit for a perennial cross, Larsen says.

Much like perennial wheat, there is potential to make perennial cereal rye two crops in one: a fall-seeded forage crop that can be grazed in the fall, winter and early spring “shoulder seasons” and act as a grain crop the rest of the year.

As a forage, the quality of perennial cereal rye has been compared positively to barley.

As grain crops, perennials generally yield 50 per cent less than annuals. However, grain yield from perennial cereal rye has been relatively high in field tests, Larsen says.

“We saw about three tonnes per hectare (45 bushels per acre) typically if we did a grain-only cut so that’s not too bad,” he says.

“The idea with perennial cereal rye is that hopefully you would just have to plant it once and have the stand survive three years or more, limiting some of your costs.”

Tackling disease susceptibility

So far, so good. But this isn’t perennial cereal rye’s first rodeo. It was introduced by the Lethbridge RDC in the early 2000s and was soon discovered to have some serious problems.

One was palatability. Quality starts to drop around the bloom stage when it becomes fibrous and coarse, making cattle disinterested, Larsen says.

But the bigger problem was that he and his team discovered today’s perennial cereal rye has an unusual genetic makeup which can lead to problems.

“We realized that the line released in Lethbridge — ACE-1 — was a tetraploid, meaning it had twice the number of chromosomes than the regular rye we were crossing it with,” he says.

“The chromosomes in the two species being crossed do not pair very well so what you get is sterility in the floret. With rye, when you don’t get seed set, the floret stays unfertilized and then ergot can get in there and that can be dangerous to livestock.”

Larsen sourced tetraploid rye material from gene banks in Germany and the U.S. to cross with ACE-1. “Then we started crossing them with the Canadian cold-tolerant line and some of the diploid wild perennial relatives of annual rye to create a second method of developing perennial cereal rye.”

The selection stage of the research process was still in its infancy when Larsen left the Lethbridge RDC, but the initial work provided a breeding template for his successors. “The way you have to do it is plant it out one year and in the second year — if it comes back vigorous — we will make our selections.

“There are some really great aspects of perennial cereal rye but some elements still remain challenging today. If you could overcome those you could have a really great forage crop.”

Management changes needed

Much of Larsen’s work focused on determining how management affected crop quality.

“If you look back at some of the extension publications that were put out in Alberta, they said the optimum time to cut the crop from a biomass quality perspective was at the boot stage,” he says.

“When we went back and emulated growth in a number of different scenarios, lo and behold we found that when we cut the crop at the boot stage it severely limited the regrowth the next year. We found you can cut the crop at the early stage before stem elongation in the spring or at the soft dough stage without any issues. Both of those stages were similar for survival, with the soft dough stage being slightly better.”

Later cutting also had a significant effect on ergot content.

“We’ve seen as high as 20 per cent ergot when cutting at the boot stage and then trying to harvest the grain in the same year, but if you treated it as a grain crop only it was down to the two to two-and-a-half per cent range, which considering the crop isn’t that bad. You would still have to clean the seed but it wouldn’t be as bad as if you managed it differently.”

Demand to drive research

Ragupathy intends to let producers guide his perennial cereal grain research in a model he calls “participatory breeding.”

“I want to set my objectives based on the market need and demand,” he says.

He wants to continue Larsen’s work to develop perennial cereal wheat as a forage source competitive with alfalfa and barley. Another goal is to conduct more research on crop rotations.

Ragupathy also hopes to work out the crop’s ergot and sterility problems and to build its cold tolerance in order to make it more adaptable to Western Canada. From there, depending on demand, he wants to breed perennial cereal rye as a dual forage and grain crop.

“Right now our focus is on silage,” says Ragupathy. “From an ergot perspective, it’s all about whether we can grow it under irrigation and other Prairie conditions. Everything is at an early stage because the research started in 2012 and not much data is available.”

He does not think he will be able to completely breed out the crop’s sterility problems due to the genetics of cross derivatives. However, he believes he will come close.

“You can’t get (rid of it) 100 per cent but you can improve that percentage. Even if you get to 20 per cent, on a larger scale that is going to be a lot of (improvement).”

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