Using molecular markers to determine barleys most suitable for malt whisky distilling

Two barley quality characters of specific interest to whisky distillers are fermentability and production of the ethyl carbamate precursor, epi-heterodendrin. The former is a quantitative trait, while the latter may be determined by a single Mendelian genetic factor. Molecular markers have been used to map, to barley chromosome 5(1H), the locus responsible for epi-heterodendrin synthesis and the inheritance of this character and a closely linked microsatellite have been followed through the pedigrees of several contemporary cultivars. Six loci, which affected fermentability in random inbred lines from a barley cross, have been mapped to chromosomes 2(2H), 3(3H) and 7(5H). This would permit the use of molecular markers in a breeding programme, to select barleys best suited for distilling. In addition, one of the loci related to fermentability mapped to an area of the genome indicated, by a previous study, to affect the activity of β-amylase, a character likely to influence fermentability. Molecular markers may, therefore, be powerful tools in exploring the contribution and detecting the mode of action of the genetical components influencing malt whisky distilling.