It’s almost 10,000 kilometres from Canada to Jordan, but barley from the southwest Asian country holds the key to breeding for stem rust resistance, according to researchers from the University of Minnesota.
Led by Eva Henningsen, plant pathologists at the university turned to a diverse collection of wild barley and discovered several accessions from Jordan that exhibited a high level of stem rust resistance.
They then hybridized these wild accessions and, in a significant discovery, found that a single dominant gene, which they designated Rpg7, was responsible for this resistance.
“This gene will be a valuable addition to breeding programs,” said Brian Steffenson, one of the plant pathologists involved. “Given that the resistant wild barley accessions were discovered in Jordan, this research will also provide clues as to where one might possibly identify additional sources of stem rust resistance.”
Stem rust is one of the biggest threats to barley production and capable of causing complete crop loss during severe epidemics. Last year, the Canadian Seed Growers’ Association inspected 129,190 acres of barley seed in Canada, according to statistics from the CSGA.
While barley is grown throughout Canada, Alberta produces the most barley of all the provinces. Alberta farmers produce approximately half of Canada’s annual barley production, according to numbers from Alberta Barley.
According to the Canadian Agri-Food Trade Alliance (CAFTA), over 65 per cent of all Canadian malt production is exported. Canadian malt is exported to more than 20 countries around the world. In 2015, Canadian maltsters exported over 575,000 tonnes of malt, valued at over $435 million—and this number is expected to grow. Malt exports will continue to increase as beer production and demand rises in Africa, Asia and Latin America, according to CAFTA data.
And since barley is also used as malt for beer and spirits and feed for animals in addition to food for humans, many industries have a vested interest in making sure barley is protected from stem rust outbreaks.
One of the most important variants of the stem rust pathogen is Ug99, which first emerged in Uganda in the late 1990s and has since spread across Africa and into the Middle East. Races in the Ug99 lineage pose a great threat to cereal production worldwide and with respect to barley are virulent on more than 95% of the cultivars worldwide. Few studies have been done to identify resistance in barley to Ug99 races, until now.
—with files from the University of Minnesota
