Tuesday, November 14, 2006

New Powdery Mildew Resistance Genes and their use to Develop Pyramids in Cultivated Wheat.

Lilian Miranda, J. Paul Murphy, David Marshall, and Steven Leath. North Carolina State Univ, 840 Method Rd Unit #3, Raleigh, NC 27695

Powdery mildew of wheat (Triticum aestivum), caused by Blumeria graminis f.sp. tritici, is an economically important fungal disease in the southeastern United States.  Breeding for disease resistance using single major genes has not provided long lasting protection against this disease and virulence shifts in the pathogen population are commonly observed. Pyramiding different major genes into a single cultivar disrupts directional selection pressure that causes resistance breakdown and should provide a more durable disease resistance. Two novel powdery mildew resistance genes present in the NCSU germplasm lines NC96BGTD3 and NC97BGTD7 were characterized using microsatellite markers. These and other previously described NCSU powdery mildew resistance germplasm lines were used to develop pyramids.  Germplasm X Germplasm crosses were made and microsatellite markers flanking the Pm genes were used to select F2 lines that were homozygous resistance for both parental genes.