Malting quality is not really a single trait, but a combination of traits, each of which is complex in nature. Most of the components of malting quality are controlled by multiple genes. This genetic complexity and the expensive assays required to measure malting quality parameters make it an excellent target for Marker-Assisted Selection (MAS Barley CAP will use a new approach to map genes for malting quality by identifying SNP markers associated with genetic variation within breeding germplasm. This research will take advantage of malting quality data routinely collected in each of the breeding programs at the Malt Quality Lab at the USDA Cereal Crops Research Unit in Madison, WI; the Anheuser Busch program uses their own lab. In addition, Paul Schwarz’s laboratory will investigate lipoxygenase and β-glucanase activity during malting..

Each year SNP marker data and malting quality data will be generated on approximately 500 of the 960 lines that are part of Barley CAP. In addition to the increased statistical power for detecting marker-trait associations, mapping in breeding germplasm will accelerate MAS for malting quality. This is because desirable alleles identified in the mapping studies are likely to be segregating in current breeding populations, and thus can be screened with markers immediately.

100 breeding lines from our preliminary yield trials in 2004 and SSR markers Identified nine marker-trait associations for some malting quality traits. Using these SSR markers we identified F2 breeding populations this summer upon which we will impose MAS. Breeding efficiency results from the fact that the genetic study was initiated only one year prior to making the crosses to generate breeding populations that will be subjected to MAS. In this sense, the genetic mapping work and breeding using MAS are done nearly in parallel.