A model of the genetic differences in malting quality between European and North American barley cultivars based on a QTL study of the cross Triumph × Morex

With 2 figures and 2 tables Abstract To study the genetic control of malting quality, in North American and European barley varieties, over five contrasting environments, 106 doubled haploid (DH) lines, from the cross ‘Triumph’ × ‘Morex’, were grown at Pullman (Washington State, USA) in 2002, Dundee (Scotland) in 2003 and 2005 and Lleida and Valladolid (Northern Spain) in 2006. The vrs locus, associated with two‐row vs. six‐row ear type, had a significant effect, as two‐row lines had higher grain protein content at all sites. This had variable effects on other malting parameters, but hot water extract (EXT) was not significantly affected at the two Spanish sites. Quantitative trait loci associated with malting characters were distributed across all seven chromosomes, but the most influential, with effects on EXT and alcohol yield, at more than one site, were on 1H, with ‘Morex’ providing the increasing allele and 5H, with the increasing allele from ‘Triumph’. Transgressive segregation, in both directions, occurred at all sites. It was concluded that crosses between European and North American germplasm could enhance quality attributes in barley cultivated across diverse environments.