Can Mapping Be Done In a Narrow Cross?.

The requirements for brewing beer from barley (Hordeum vulgare L.) malt are specific and unique for each brewer. Two major brewers that utilize six-rowed barley malt in the United States (US), Anheuser-Busch InBev (ABI) and MillerCoors Brewing Company (MillerCoors), require very different malt quality parameters for producing their products.  Robust and Stander are two closely related cultivars that differ greatly in agronomic performance and malt quality.  Robust fits the requirements of MillerCoors and Stander has many of the parameters desired by ABI.  A total of 54 doubled-haploid (DH) lines and the parents from the Robust x Stander cross have been evaluated at nine locations in North Dakota and one location in Idaho in the past five years.  Agronomic data were collected at all locations and cleaned samples from six of the locations were micro-malted at NDSU. A linkage map using 168 DArT and SSR markers was constructed.  This map was used to identify QTL for free amino nitrogen (FAN) in chromosomes 5H and 6H, wort color in chromosomes 2H and 5H, and soluble protein and Kolbach index in chromosome 6H.  Additionally, QTL for different fermentable sugars were mapped to chromosomes 4H, 5H, and 6H. An additional 139 Robust x Stander DH lines were generated in 2009, and will be evaluated with the current DH population in the summer of 2011 at three locations. A map utilizing all 193 DH lines is being developed using existing DArT and SSR markers, and 200 new SNP markers. The new map will be used to better localize QTL controlling agronomic and malt quality traits in the larger population.