One size doesn't fit all when it comes to disease resistance needs for wheat and barley varieties in Western Canada, says Dr. Ron Knox of Agriculture and Agri-Food Canada (AAFC). This is an issue the region's gatekeepers for crop variety registration grapple with as they make decisions on how to evaluate and recommend new crop lines for registration support.

"The challenges of how to set appropriate disease performance standards and to recognize sub-regional differences is a frequent source of debate," says Knox, a cereal pathologist and biotechnologist at AAFC in Swift Current. "On the one hand, protecting the industry from poor performing or inferior quality varieties is a major concern. But on the other hand, flexibility is required to accommodate regional differences in disease pressures and ensure varieties with net benefits for the industry are not unduly turned down due to disease performance shortcomings."

Knox is a member of the Prairie Registration Recommending Committee for Grain (PRRCG), one of several organizations nationwide with a mandate from the Canadian Food Inspection Agency (CFIA) to recommend new crop lines for approval as registered varieties in Canada. The PRRCG's mandate covers several grain crops - including wheat and barley - for the Canadian Wheat Board (CWB) designated area of Western Canada. Members of the organization include crop breeders, grain experts and other stakeholders.

Knox offers an insider's view on the challenge of disease evaluation in the registration system, in a feature article available in the new April 2004 edition of Western Grains Research Magazine, available on the Western Grains Research Foundation (WGRF) Web site: www.westerngrains.com. Western Canadian wheat and barley growers are major investors in wheat and barley breeding research through the Wheat and Barley Check-off Funds, administered by WGRF. The Research Magazine offers "Ideas and issues for farmer research investors."

Knox serves on the disease evaluation team of the PRRCG's Wheat, Rye and Triticale Subcommittee. The disease evaluation team is charged with evaluating crop lines for merit in disease performance, to provide guidance to the full subcommittee. The subcommittee also has evaluation teams for agronomy and quality. Once it hears reports from the evaluation teams, it uses this information to weigh the net benefits and liabilities of a particular crop line, before voting on whether or not to recommend the line for registration by CFIA.

"At the disease evaluation team level, we maintain a set of guidelines that outline the disease criteria we evaluate and how important they are. Disease pressures constantly change, so we revise these guidelines regularly to keep them up to date," says Knox. "We often have debates about how rigid the guidelines should be, but typically everything still comes down to judgement of net merit."

Disease pressures can vary greatly across the Prairies. But ultimately the PRRCG makes one 'yes or no' call on whether to recommend a line for the region as a whole. That's why industry awareness is crucial to choosing the best variety for a particular area, says Knox.

"Our evaluations recognize differences in growing areas. For example, we'll say something is suitable for the eastern Prairies but not the west. But ultimately you have to make a yes or no call, and once the variety is registered, there's no policing of the system to govern where exactly a variety can or should be grown. The weight then falls on the information that goes with a variety package - it's left up to the producers and those promoting the variety to understand and to find the best adapted localities for varieties."

The disease evaluation team must balance many factors when judging a variety with respect to a disease such as Fusarium Head Blight (FHB), he says. FHB resistance has proven very costly and elusive for breeding programs. It's a potentially devastating disease, but hasn't yet proven to be a major problem outside the eastern Prairies.

"Our approach with respect to Fusarium has been to impress the importance of this disease upon the subcommittee, while being realistic about how difficult it is to get resistance and recognizing that so far the disease has been a far greater threat in the eastern Prairies than in the western Prairies. However, because we have concerns about the disease spreading and increasing, we still think FHB resistance needs to be notched up a bit across the Prairies."

The April edition of Western Grains Research Magazine also includes a Q&A with outgoing PRRCG Chair Dr. Mario Therrien, on the future of PRRCG, and an article on how WGRF's Check-off Reserve Funds protect farmers' research investment.