48 | Advancing Seed in Alberta Combine this with the fact not all clubroot pathotypes (races) have been identified, and it’s therefore difficult, explains Weidler, to develop a canola variety that is resistant to all potential pathotypes to which a plant may be exposed. Dr. Igor Falak reminds us that it was in 2013 that a new clubroot pathotype was identified, one to which all canola varieties on the market carrying resistance to the original 2003 pathotype were susceptible. Although hybrids with the initial type of resistance continue to hold their own on most infested acres, the number of fields with the new pathotype is increasing annually. Falak, senior research scientist with Corteva Agriscience, blames this situation on “years of canola-on-canola.” In addition, he notes that although clubroot “is similar to another disease of canola (blackleg), where canola products may carry race specific resistance,” clubroot-resistant canola varieties “do not have ‘fallback’ resistance mechanisms, unlike blackleg-resistant products that also have a different type of stable resistance.” More breeding challenges are found in the fact that because canola plants carry no clubroot resistance genes, all the major seed companies are actively testing resistance genes found in rutabaga, cabbage and turnip. However, Weidler notes that because these species are only remotely related to canola, it’s far from easy to transfer genes between them without also transferring additional unwanted genetic “baggage” that negatively impacts yield, canola quality or agronomics. If all this wasn’t enough, clubroot is a challenging organism to deal with, having unique characteristics – described by Weidler as a form of life “somewhere between a bacterium and a fungus.” Christianson concludes that the biggest challenge in creating clubroot-resistant canola seed is to introduce resistance “while continuing to improve hybrid performance for yield, maturity, standability, resistance to other diseases, harvestability, seed quality and all of the other attributes that are important to growers’ success.” Breeding Steps to Develop Clubroot-Resistant Canola Seed Christianson says the steps involved in breeding clubroot- resistant varieties are relatively simple, and that any breakthroughs relating to resistance genes “are really just the discovery and characterization of more of them through concerted screening efforts.” A bundle of plants from a susceptible product versus clubroot-resistant hybrid 45H29 under disease pressure (Leduc, Alberta). Notice clubbed roots and premature ripening. Photo: DowDuPont Resistant product 45H29 (left) under severe clubroot pressure versus susceptible product (right) with premature ripening and stunted growth. Photo: DowDuPont Walter Smith 204-825-2000 Airth Farms Ltd. 403-362-4372 Mercer Seed Ltd. 403-327-9736 Sleepy Hollow Seeds Ltd. 403-647-2228 Specialty Seeds Inc. 403-545-6018 Stamp Seeds 403-739-2233 Willms Seed Farms 403-655-2434 Purchase certified Gateway seed from one of our authorized dealers GATEWAY Winter Wheat AAC GATEWAY Gamechanger  Consistent Yields  Best Lodging  Medium Maturity  High Protein  Shorter  Less Fusarium AAC Gateway The New Gold Standard in Quality and Agronomics for Winter Wheat To learn more visit www.seeddepot.ca