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Heritage wheat more rust resistant than modern ones

Walk with Gary Martens down a row of test plots the length of a football field and you’re walking backwards in time through the history of wheat in Western Canada.

Start with the latest varieties: Carberry (introduced in 2009) and Waskada (2007). A little farther down you meet Glenlea (1972) and Manitou (1965). Still farther along are Thatcher (1935) and Reward (1928). Then comes Marquis (1911), the first wheat variety bred in Canada. Finally, at the end of the row, stands Red Fife, the first wheat grown commercially in Manitoba when it became a province in 1870.

The old varieties have long since been replaced, mainly because of their susceptibility to rust. But look closely, Martens tells a group of visitors. The leaves on recent varieties are spotted with telltale signs of rust. The leaves of Red Fife and Marquis appear rust free.

It looks as if the oldest varieties are more rust-resistant than the newer ones. Why is that?

As Martens, a University of Manitoba plant science instructor explains, rust evolves to adapt to new wheat varieties bred for rust resistance. As a result, plant breeders are always in a race to stay one step ahead of constantly evolving rust pathogens. Today’s pathogens are vastly different than they were 100 years ago. But the old wheat varieties remain the same.

So just by standing still, Red Fife and Marquis, which were formerly devastated by rust, are now actually ahead of the rust game.

“The original rust that infected Red Fife and Marquis is not around any more,” says Martens. “They’re not susceptible to today’s rust.”

For that reason, plant breeders might return to these heritage varieties, isolate genes and use them to develop new, improved varieties, Martens suggested.

Old wheat varieties also have other things to offer, Martens told the group on a July 21 crop tour at the University of Manitoba’s Ian N. Morrison Research Farm. For one thing, their quality remains superb.

Martens served slices of delicious, chewy whole-wheat sourdough bread milled from Red Fife grown by farmers in Saskatchewan and baked by the Sobey’s grocery chain.

Red Fife is also grown today on Vancouver Island, where a long growing season and temperate climate allows the late-maturing variety to flourish, Martens said.

Despite its age, Marquis was the top standard for milling wheat until recently. “As good as or better than Marquis” was the industry benchmark for years.

It’s true that modern wheat varieties outperform the old ones in many ways, Martens acknowledged.

For example, today’s varieties mature at least 10 days sooner than heritage varieties – an important consideration in a province where Winnipeg’s average date for the first autumn frost is September 22.

Another consideration is yield. Martens said historical records and other data show Red Fife during its heyday in Manitoba averaged a mere 18 bushels an acre. Last year, Carberry and Waskada averaged over 40 bushels an acre – 120 per cent more than Red Fife.

But only part of that increase is due to genetic advances, said Martens.

His research shows that, on average, only 40 per cent of yield increases in modern varieties is due to genetic improvements. The remainder comes from advances in soil nutrition, weed control and other modern agronomic practices.

The take-home message is that farmers play an even greater role than plant breeders in attaining higher yields, Martens said.

“Farmers apply proper agronomic practices to get the genetic potential out of the wheat yield. The breeder can do so much to provide a foundation but that’s what the farmers have to build on.”

To be fair, genetics can make a crop resistant to disease. It may not increase yield but it protects it, Martens added. [email protected]

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