Quantitative trait loci for germination and malting quality characters in a spring barley cross

Absence of dormancy and good malting quality are significant targets of many barley (Hordeum vulgare L.) breeding programs. Expression of dormancy is strongly affected by the environment, and malting quality assays are expensive. Both groups of characters would therefore be suitable for marker-assisted selection. The objective of this study was to identify quantitative trait loci (QTL) controlling germination and malting quality characters in a cross between the spring barley genotypes 'Blenheim' and E224/3 as an initial step in the development of a marker-assisted selection scheme. The characters were measured on a random sample of doubled haploid lines from the cross grown in replicated trials each year from 1989 to 1992. The QTL were revealed by regression analysis of the data with marker scores from 120 mapped polymorphic loci. The QTL controlling hot water extract were located on barley Chromosomes 2, 3, and 7. Milling energy was largely controlled by a factor on Chromosome 7, a region also associated with extract viscosity. The dense dwarfing gene on Chromosome 3 was associated with a reduction in grain N but this was found to be a dilution effect as the locus had previously been found to be associated with an increase in grain yield. The germination characters showed little relationship with each other, possibly reflecting different mechanisms of control.