Mapping of QTL for malting quality attributes in barley based on a cross of parents with low grain protein concentration

Abstract

The barley population used for this research was derived from a cross of parents inherently low in grain protein concentration (GPC). Because of the established inverse relationship between GPC and malt extract, our aim was to characterise quantitative trait loci (QTL) that affect eight malting quality attributes in the hope of identifying novel alleles. The mapping population comprised 180 doubled haploid progeny of a cross between VB9524 with ND11231 ∗12. QTL analysis was based on a 167-point genetic linkage map and malting quality data obtained by micro-malting grains from two trial sites. The number of QTL identified for individual traits ranged from 3 to 5. The distribution across chromosomes showed a paucity of QTL on chromosome 1H and 6H (with one locus each) and a high concentration on chromosome 2H (nine loci). Together, the QTL explained 20–58% of the phenotypic variation observed for each trait. The inclusion of GPC as a covariate increased the number of QTL identified for malt extract and diastatic power, largely due to increased power of detection.