Markers to a common bunt resistance gene derived from 'Blizzard' wheat (Triticum aestivum L.) and mapped to chromosome arm 1BS.

Common bunt, caused by Tilletia caries (DC.) Tul. & C. Tul. and T. laevis J.G Kuhn, is an economically important disease of wheat (Triticum aestivum L.) worldwide. The resistance in the winter wheat cultivar 'Blizzard' is effective against known races of common bunt in western Canada. The incorporation of resistance from Blizzard into field-ready cultivars may be accelerated through the use of molecular markers. Using the maize pollen method, a doubled haploid population of 147 lines was developed from the F(1) of the second backcross of Blizzard (resistant) by breeding line '8405-JC3C' (susceptible). Doubled haploid lines were inoculated at seeding with race T19 or T19 and L16 and disease reaction was examined under controlled conditions in 1999 and natural conditions in 2002, and 2003. Resistant:susceptible-doubled haploid lines segregated in a 1:1 ratio for bunt reaction, indicating single major gene segregation. Microsatellite primers polymorphic on the parents were screened on the population. Initial qualitative segregation analysis indicated that the wheat microsatellite markers Xgwm374, Xbarc128 and Xgwm264, located on wheat chromosome 1BS, were significantly linked to the resistance locus. Qualitative results were confirmed with quantitative trait locus analysis. The genetic distance, calculated with JoinMap, between the bunt resistance locus and overlapping markers Xgwm374, Xgwm264 and Xbarc128 was 3.9 cM. The three markers were validated on doubled haploid populations BW337/P9502&DAF1BB and Blizzard/P9514-AR17A3E evaluated for common bunt reaction in the growth chamber in 2007. These markers will be useful in selecting for the common bunt resistance from Blizzard and assist in identifying the resistance among potential new sources of resistance.