Status of Bunt Resistance in Western Canadian Spring Wheat and Triticale

The reaction of western Canadian spring wheat and triticale to a composite of races of common bunt (Tilletia caries and T. foetida) was assessed in field studies conducted over 2 yr at three locations. Triticale and durum wheat were designated immune or highly resistant. Among cultivars of hard red spring wheat, Columbus was the most resistant followed by Katepwa, Leader, and Lancer. Neepawa, Park, and Marquis were intermediate in resistance. Roblin and Laura were susceptible. The Canadian Prairie Spring wheats HY320 and HY360 were highly susceptible and susceptible, respectively, whereas Oslo was intermediate in resistance. The utility wheats Wildcat and Glenlea were highly susceptible and intermediate, respectively. The soft white wheats Owens and Fielder were susceptible. The reaction of the cultivars to individual bunt races was evaluated under controlled environment conditions to identify specific Bt resistance genes. This revealed the presence of Bt1 in the cultivar Canuck and Bt10 in the line BW-553. Resistance in the other cultivars of hard red spring wheat appeared to be race nonspecific in nature. Race specificity was apparent in durum wheat but the virulence pattern could not be employed to identify specific Bt resistance genes. The potential impact of seeding large acreages to spring wheat cultivars that are highly susceptible to common bunt is discussed.Key words: Tilletia caries, Tilletia foetida, bunt (common)