Thin Meiw (Alek) Choo, a breeder at the Eastern Cereal and Oilseed Research Centre in Ottawa, is working with a team to develop high-yielding, FHB-resistant barley cultivars for Eastern Canada. Photo courtesy of Thin Meiw (Alek) Choo.
Barley is the fourth-largest crop in Eastern Canada, after the standard rotation crops of soybeans, corn and wheat. Approximately 150,000 hectares of land in Eastern Canada were seeded to barley last year, which led to a harvest of 460,000 tonnes of grain.
Fusarium head blight (FHB) is a serious concern in barley. “The outbreaks of FHB vary from year to year, with 2009 and 2010 most severe in Eastern Canada,” says Thin-Meiw (Alek) Choo, a breeder at the Agriculture and Agri-Food Canada (AAFC) Eastern Cereal and Oilseed Research Centre in Ottawa (now called the Ottawa Research and Development Centre). “The disease, caused principally by Fusarium graminearum Schwabe, can result in mycotoxin contamination such as DON in the grain. During those years, many barley crops were contaminated with DON.”
AAFC breeders have developed several barley varieties (see sidebar for agronomic details) that have proven more resistant to Fusarium head blight than many others. These include AAC Starbuck (released in 2014), AAC Azimuth (2013), AC Minoa (2010) and Island (2002). Choo reports, for example, that under natural conditions in Prince Edward Island from 2004 to 2012, Island contained only 0.2-2.1 mg DON/kg while susceptible cultivars contained up to 17.6 mg DON/kg. During the epidemic year of 2010, AAC Azimuth contained only an average of 1.7 mg DON/kg, while susceptible six-row cultivars contained an average as high as 5.1 mg DON/kg.
AAC Azimuth and AC Minoa are well adapted to Ontario, AAC Starbuck is well adapted to Quebec and the Maritimes, and Island is well adapted to all of Eastern Canada. These performance differences mostly relate, says Choo, to the varying climatic conditions of the regions.
Breeding program update
The present barley-breeding program run by Choo and his colleagues Richard Martin, Allen Xue, Marc Savard and Barbara Blackwell, continues to develop high-yielding, FHB-resistant barley cultivars for Eastern Canada. “Many elite lines are now under intensive testing,” Choo notes. “We have crossed our local varieties with FHB-resistant germplasm from different places in the world and have produced many breeding lines from these crosses. Some of them have been screened in our FHB nursery and are now under evaluation for agronomic traits.” The team has 12 elite lines now being evaluated in the Maritime Barley Registration and Recommendation Tests, 10 elite lines in the Quebec Barley Registration and Recommendation Tests, and 10 elite lines in the Ontario Barley Orthogonal Trials. “Hopefully,” Choo says, “some of them will be released as new varieties in the next few years.”
In terms of specifics on genetic resistance, Choo say there is no major resistance gene for FHB in barley and that this makes improvement for resistance a slow breeding process. “Because of this, we use an indirect approach to mitigate the severity of DON contamination in barley,” he says. “Two-row barley is more resistant to DON accumulation than six-row barley. Hulless barley contained less DON than covered barley, and black barley is more resistant to DON accumulation than yellow barley.”
Choo and his colleagues have found black barley to be more resistant to DON accumulation because it contains higher total phenolic content than yellow barley. In lab tests, the phenolic acids in black barley have been shown to inhibit the growth of F. graminearum and F. culmorum. Black barley also contains flavonoids, which also play a role in FHB resistance. Some flavonoids have been shown to severely inhibit the growth of F. graminearum and other fungi on culture medium. In addition, preliminary results indicate that black barley contains more lignin than yellow barley, and lignin/lignification may create some physical barriers to inhibit Fusarium growth.
In terms of yield, 26 varieties of barley were compared in the 2014 Ontario Cereal Crops Committee spring barley trials in three areas of Ontario (see www.gocereals.ca/bat3.php). The averages for each area were 98, 89 and 76 bushels per acre. “Chapais has been the dominant barley variety in Eastern Canada for many years and now, many varieties have out-yielded Chapais,” Choo notes. “We expect that future barley varieties will have higher yield, be
better resistant to FHB, and be better resistant to lodging. In addition, malting barley and food barley varieties will be developed to provide some niche markets for Eastern Canada.”
Newest barley varieties
Island is a two-row, spring feed, non-malting barley cultivar developed by the Eastern Canada Barley Breeding Group, Agriculture and Agri-Food Canada. It is named after the province of Prince Edward Island and was registered in mid-2002. Island is well adapted to Eastern Canada. The plant has erect juvenile growth, green coleoptile, blue-green leaves and intermediate flag leaf attitude. Other characteristics include purplish auricles, fine, dark green and waxy stems, a v-shaped collar and a straight neck. The spike is two-row type with tapering shape and lax density. The spike is medium length with nodding attitude, rough awns, medium (equal to the length of glume) and rough glume awns, purplish lemma awn tip and green glume awn tip. The kernel is covered, long and medium width, with long rachilla, short rachilla hairs, yellow aleurone and incomplete horseshoe basal marking. Island is susceptible to net blotch, scald, septoria leaf blotch, spot botch, and leaf rust, but highly resistant to powdery mildew and moderately resistant to barley yellow dwarf virus and Fusarium head blight.
AAC Azimuth is a six-row hulless non-malting barley (Hordeum vulgare L.) cultivar developed by the Eastern Canada Barley Breeding Group, Agriculture and Agri-Food Canada. AAC Azimuth was registered in early 2013. It is well adapted to the province of Ontario. The plant shows erect juvenile growth, blue-green leaves, upright flag leaf attitude, white auricles. Other characteristics include thick, dark green and pronounced waxy stems, a v-shaped collar and straight neck. Its spike is six-row type with parallel shape, medium density, medium length, erect attitude, smooth lemma awns, longer than the length of glume with smooth glume awns, green lemma awn tip and green glume awn tip. The kernel is hulless with medium length, medium width, medium rachilla length, short rachilla hairs, yellow aleurone and incomplete horseshoe basal marking.
AAC Starbuck is a two-row, hulless barley cultivar developed at the AAFC Eastern Cereal and Oilseed Research Centre. It was registered in mid-2014. AAC Starbuck is well adapted to Quebec and the Maritimes. The plant has erect juvenile growth, green coleoptile, green leaves, upright flag leaf attitude and purple auricles. The waxy stems are fine, medium green, and pronounced with a v-shaped collar and straight neck. The spike is two-row type with parallel shape, lax density, long spike, horizontal attitude and rough lemma awns. It is longer than the length of glume, with rough glume awns, green lemma awn tip, green glume awn tip. The kernel is hulless with medium length, medium width, long rachilla and rachilla hairs, and yellow aleurone. It is susceptible to net blotch, spot blotch, scald, and speckled leaf blotch. The variety is resistant to powdery mildew and leaf rust, and low in DON content (Fusarium graminearum Schwabe). It is moderately susceptible to net blotch and spot blotch. It is resistant to scald and barley yellow dwarf virus and moderately resistant to powdery mildew. This variety is susceptible to leaf rust and low in DON content.
AC Minoa is a two-row; spring feed barley (Hordeum vulgare L.) cultivar developed by the AAFC Eastern Canada Barley Breeding Group and registered in 2010. It has high yield, high test-weight and good resistance to powdery mildew and DON accumulation. AC Minoa performs well in the state of New York and in the province of Ontario.