A Breed Apart

-

Plant breeder Robert Graf. Photo: Hamis Naeem

For more than three decades, Rob Graf’s dedication to wheat breeding in Canada has led to his contribution asprincipal developer of 12 wheat cultivars and co-developer of 12 other wheat and triticale cultivars. He’s now focusing his considerable abilities on winter wheat.

Last fall, Robert Graf, a wheat breeder at Agriculture and Agri-Food Canada’s (AAFC) Lethbridge Research and Development Centre, seeded his 34thyear of plot trials and nurseries.

Graf has headed up AAFC’s winter wheat breeding program since 1999, but he began his career 12 years earlier. Shortly before completing his PhD in plant breeding and agronomy at the University of Saskatchewan, he was hired by the Saskatchewan Wheat Pool, where his focus was primarily on developing Canada Western Red Spring (CWRS) wheat varieties. During that time, he developed three varieties, including McKenzie, the first doubled haploid wheat variety registered and released in North America. It remains Canada’s most successful, privately developed CWRS wheat variety to date.

“It’s no longer grown on any appreciable acres, but it was among the top five CWRS varieties for almost 10 years and has been used extensively as a parent,” says Graf. “Having producers and other breeders see value in what we do is what we strive for — it’s part of what makes us tick.”

Today, Graf works exclusively on winter wheat, primarily of the Canada Western Red Winter (CWRW) class. Although many of the desired characteristics are the same as any other wheat class, such as high yield, excellent agronomics, good disease resistance and the appropriate quality profile, winter wheat varieties also need good cold tolerance to allow them to survive the winter, which presents added challenges for breeders.

“Because winter wheat has a vernalization requirement or, in other words, it needs that cold period during its seedling phase so it can become reproductive, we’re not able to use contra-season [warm winter location] nurseries like spring crop breeders do to speed up the breeding process. That means the breeding cycle is longer for a winter cereal or a fall sown crop,” says Graf.

Focus on Quality Characteristics

One of Graf’s main projects, funded by the cluster program of the Canadian Agricultural Partnership — whose funding partners include the Alberta Wheat Commission, Saskatchewan Wheat Development Commission, Manitoba Wheat and Barley Growers’ Association, Saskatchewan Winter Cereal Development Commission, Winter Cereals Manitoba, and the Western Grains Research Foundation — is to develop field-ready CWRW cultivars for Western Canada. Funding from the Ducks Unlimited Canada Western Winter Wheat Initiative enhances these efforts.

Another project Graf is working on is the development of “premium quality” winter wheat to add more value for producers and processors. “One of the challenges with winter wheat has been marketing,” says Graf. “Historically, we’ve had a couple of quality deficiencies that, if we could correct, would go a long way toward increasing the farm gate price for hard red winter wheat. And by increasing the price, along with the yield advantage that winter wheat already has, I feel it would drive acreage.”

The first characteristic that Graf is trying to improve is protein concentration. “We are working on increasing the protein potential from a genetic standpoint, and we have germplasm that makes us very optimistic that this can be achieved,” says Graf. “We’ve developed several lines that show much better protein concentration along with other desirable traits and are using them as parents for further improvements.”

Graf was recently awarded the 2020 Canadian Plant Breeding and Genetics Award, co-sponsored by the Canadian Seed Trade Association and Germination magazine. Photo: George Clayton.

The second quality characteristic — flour water absorption — has been far more difficult to improve. When flour is milled, the flour absorbs a certain amount of water upon mixing to create dough, but winter wheat generally has lower water absorption than spring wheat, so it produces less dough and therefore fewer loaves of bread; a disadvantage to a baker.

“We’ve been working on this characteristic for over 15 years and finally have some promising lines,” says Graf. “We’re at a point now where we’re crossing high protein lines with those that have improved water absorption to develop varieties that correct both deficiencies. The end result, at some point, may be quality that’s comparable to our premium quality Canada Western Red Spring class.”

If Graf does that it will be something that no one else has tackled, and he already has a line in registration trials that could be a prototype.

Over the past 20 years, Graf and other western Canadian winter wheat breeders have also made a lot of progress incorporating disease resistance into new varieties — characteristics that were rare in winter wheat when he started.

In fact, Graf has a line that was approved for registration in 2019 (W569) that exceeds the requirements for all five priority one wheat diseases; Fusarium head blight, leaf rust, stem rust, stripe rust and common bunt.

“Disease resistance has been a major focus of my program, but I would still say that the resistance package in our Canadian winter wheat varieties is rather shallow. In other words, most of the resistance genes are on their own because we don’t have effective pyramids of a number of genes that would serve as backups. If there’s a race shift for a particular disease it could wipe out the resistance in several varieties, but we’re working very hard on that and making wonderful progress,” says Graf.

Graf has also produced a hard white wheat variety for specialty markets — AAC Icefield — and is working on soft winter wheat for the food processing and ethanol markets.

Changing Landscape

There have been a lot of changes since Graf began his career back in 1987, not the least of which was the introduction of doubled haploid technology in the early 1990s.

“When McKenzie was registered in 1997, it was considered to be ‘biotech wheat,’ but doubled haploid technology is simply regarded as a regular plant breeding process these days, as it should be. There was a lot of excitement at the time and Canadian breeding programs were early to embrace this technology because it speeds up the process dramatically,” says Graf. “Doubled haploidy has made a big difference, particularly in winter wheat.”

So has the development of molecular markers and sequencing of the wheat genome, says Graf.  “We know wheat has over 107,000 genes, and the reference genome identified about four million genetic markers,” he says. “The big challenge now is to associate the traits that we’re interested in with those markers. And along with that, we need an understanding of what the effects and interaction of the various genes are. So, there’s a huge amount of work to be done, but the future is really bright.”

Challenges Ahead

In the future, Graf sees gene editing as a tool that could move the industry forward in many exciting ways, but that doesn’t mean the plant breeder’s job is going to be without its challenges.

“Our ability to very precisely change gene sequences, possibly turning genes on or off, or reengineering defeated disease resistance genes are examples of some of the things being thought about,” he says.

“There are countless possibilities, but plant breeders will still need to incorporate the lines with these changes back into their breeding programs. It also has to be remembered that there are likely to be pleiotropic effects, something that plant breeders deal with all the time. When one thing is changed various other traits are often affected, things you may not expect. A very simple example is as yield is increased, there’s a negative correlation with protein concentration. The plant breeder’s job is to try to shift those correlations as much as possible and expand the boundaries of those relationships.”

Graf also sees challenges in terms of explaining breeding technologies to people who aren’t well informed about science and food production, and determining a new funding model for cereal breeding in Canada.

“Currently, there are value creation discussions going on and I think it’s fair to say producers will be expected to contribute more towards plant breeding,” says Graf. “That’s not necessarily a bad thing since it could enhance the tremendous success of our public breeding efforts; efforts that have been in partnership with various producer groups. At the same time, having worked in private industry, I have first-hand knowledge of the advantages they might bring, and developing a model that encourages private investment while maintaining a strong public presence is important. The question becomes, what is the right public-private balance? How this evolves, and what Canadian cereal breeding looks like in the future, is something we need to get right.”

Climate change is another area where Graf sees challenges for breeders, especially as, with milder winters, the potential exists for new pests to move northwards and diseases to evolve more quickly, but he also sees technology providing a lot of solutions as well.

“Since 2000, we’ve seen shifts in stripe rust races that have higher temperature optima, so they’re much more virulent,” says Graf. “There’s also the well-known threat of Ug99 stem rust races. Those are just a couple of examples that, as plant breeders, we need to be ready for and always be forward looking. With the technologies we’re using now and future technologies such as genomic selection and gene editing, we’ll become more efficient in our breeding efforts, and hopefully bring advancements quicker than ever before.”

To date, Graf is the principal developer of 12 wheat cultivars (nine winter wheats and three spring wheats) as well as co-developer of 12 other wheat and triticale cultivars.

He was recently announced as the recipient of the 2020 Canadian Plant Breeding and Genetics Award, co-sponsored by the Canadian Seed Trade Association and Germinationmagazine.  He received the ASTech Leadership Foundation Award for Innovation in Agricultural Science in 2016, the AAFC Gold Harvest Award for Innovation, Collaboration and Service Excellence, and was co-author of the Canadian Society of Agronomy Best Paper in 2015. Graf has also been awarded Honorary Life Memberships by both the Alberta Seed Growers’ and the Canadian Seed Growers’ Associations.