46 GERMINATION.CA MARCH 2018 THERE ARE PRECIOUS resources con- tained in Canadian canola seed and now growers have an innovative tool to better protect them. These resources are the genes that provide canola plants with resistance against blackleg. In the past, grow- ers managed blackleg (there are at least eight different blackleg strains in Western Canada) by planting a canola variety different from the one they had planted on the same field, usually two or three years before. In short, growers had to rely on luck that the new variety would contain different resistance genes than the variety planted previously, explains Shaan Tsai, product development manager for oilseeds and pulses at Canterra Seeds. “Growers never quite knew exactly what type of resistance they had in the variety they were using,” he says. “They had to go with a general field rating that was based on specific locations at the time of regis- tration testing, a rating that in many cases represented resistance to races of the disease that are vastly different than what farmers could expect in their own fields.” Tsai says this has ultimately led to many a farmer experiencing disap- pointing yield losses due to black- leg, and points to a recent study by Agriculture and Agri-food Canada scientists that found even low levels of infection could lead to yield losses of up to 20 per cent. Ralph Lange, team leader of crop pathology and molecular biology at InnoTech Alberta, echoes the senti- ment. “We used to tell people to just plant another variety on the chance that it would have different resistance genes,” he says. Therefore, in many cases the blackleg fungus has been presented with canola varieties with resistance genes it could overcome, and in recent years, some grow- ers have noticed increased blackleg severity in their ‘R’ and ‘MR’ varieties. To steer this situation in a new direction, the Canola Council of Canada (CCC), the Blackleg Steering Committee, and the Western Canadian Canola/Rapeseed Recommending Committee are imple- menting a much more specific rating system, an idea first developed in Australia. In short, instead of guess- ing, growers will be able to deter- mine over time which genes are not working against whatever blackleg strain they’ve got, and can switch to a variety with a different resistance gene(s) — thereby gaining a much better chance of improved crop per- formance against the pathogen. “These new resistance labels will be important for producers who have DESIGNERGENES: WHAT’SONTHELABEL? Labelling seed with the specific resistance genes is allowing blackleg in canola to be better controlled, both at the farm and provincial levels. Treena Hein been noticing increasing blackleg issues in their fields,” notes Canola Council agronomy director Clint Jurke. “If producers have not had any issues with blackleg, then they can keep doing what they are doing. This is for those that are experienc- ing higher levels of disease than they would like to have.” As many as 10 new blackleg resistance labels will be applied to various ‘R’ and ‘MR’ canola varieties in the coming years, with the letters A, B, C, D, E1 , E2 , F, G, H and X used to identify major resistance genes present (see sidebar for variety examples). Tsai notes that while these labels will improve a grower’s odds at zero- ing in on their races and keeping the disease in check, he adds “from what I understand, we are getting very close in the development of a quick test to better characterize the blackleg races in a field and it will likely not be long before a grower can submit a sample to their local diagnostic lab, get a full profile of the blackleg pathogens in their field, and make their variety selections accordingly. In the mean- time, there are ‘multigenic’ varieties available with several types of major genes in a single variety that can offer a broad defence against the disease.” Jurke notes that ‘multigenic’ is a term used differently by various par- ties (e.g. to refer to quantitative resist- ance, stacks of R genes, or a stack of R genes with quantitative resist- ance) but that industry consensus is expected soon. Records Critical Frequent and accurate scouting with excellent record keeping is essential for determining if the genes in a In the past, growers managed blackleg by planting a canola variety different from the one they had planted on the same field, usually two or three years before.