Marker-based selection in barley for a QTL region affecting α-amylase activity of malt

Abstract

In the development of barley (Hordeum vulgare L.) cultivars for malting purposes, it is usually not possible to select for malt quality characteristics in early generations because of the high cost associated with micromalting large numbers of grain samples and assessing quality traits on the resulting malt samples and because of the sensitivity of quantitative malt quality traits to environmental variation. Thus, barley malting quality may be a good candidate for marker-assisted selection. Here, the objective was to use marker-based selection to manipulate a malt quality characteristic, -amylase activity, in a barley breeding population. Marker-based selection was applied among F₂:₃ lines from the cross ‘Morex’/‘Labelle’, targeting Morex alleles in a region of chromosome 7(5H) that had previously been found to affect -amylase activity in the cross ‘Steptoe’/Morex. The target region was represented by two polymerase chain reaction (PCR) markers. Selected lines were grown in field plots in two years. Agronomic and grain quality data were measured. Grain samples were micromalted and assessed for malt quality traits. Selection for the Morex allele at two PCR markers on chromosome 7(5H) was effective in increasing -amylase activity. It was concluded that marker-based selection for a quantitative trait locus could be effective even when applied in a population other than the mapping population.