Advanced Backcross QTL Mapping of Yield and Malt Quality in a Wild x Cultivated Barley Mapping Population

While many sources of disease resistance can be found in wild barley (Hordeum vulgare subsp. spontaneum), the utility of wild barley for complex yield and malting quality characteristics is less well understood.  To identify whether wild barley contains useful alleles for yield and malting quality, we mapped QTL for a series of malt quality measures, yield, heading date, height, and lodging in an advanced backcross population derived from a wild x cultivated cross.  The population was derived from a 2-row malting cultivar recurrent parent Harrington and a wild barley donor parent OUH602 which exhibits resistance to several pathogens.  Improved yield and malting quality are products of breeding, and would not necessarily be selected on in wild populations.  Still, useful variation for these traits might be present, particularly as genetic diversity of breeding programs may become limited over time.  Understanding the genetic basis of these traits in wild barley may increase the effectiveness of introgression and utilization of exotic germplasm in a breeding context.  Using 111 SSR markers and 5 field seasons of phenotypic data, we find that OUH602 does not provide beneficial alleles for yield and malting quality, with the exception of soluble protein content for which both parents contributed favorable QTL.  Heading date has a strong QTL on chromosome 2H which may be associated with the photoperiod (Ppd-H1) gene located in the vicinity and yield seems to be largely influenced by the brittle rachis (Brt1 and Brt2) genes on chromosome 3H.  To further explore the interaction between traits, we identified several trait correlations which can inform decisions in a breeding context.