Submitted to: Proceedings International Barley Genetics Symposium
Publication Type: Proceedings
Publication Acceptance Date: 10/22/2000
Publication Date: N/A
Interpretive Summary: The breeding of barley lines that have improved malting quality is impeded by the fact that many of the traits needed in malting barleys are not due to single genes, which are easy to manipulate, but are controlled by multiple genes, each of which contribute a small amount to the overall quality. It is hard to manipulate these so-called 'quantitative' genes using conventional breeding methods. This paper reports on one way to use molecular biology to detect these genes and to incorporate them into improved varieties. A 2-rowed and a 6-rowed malting barleys were crossed and the resulting plants were analyzed for several malting quality traits. Seventeen otherwise undetectable gene locations affecting malting quality were found. Several of these affected multiple malting quality aspects. Genes affecting nearly all aspects of malting quality were located at the same place as the gene(s) that determine whether a barley is 2- or 6- rowed, and these genes were the strongest found. This information will be used by barley breeders to develop improved malting barleys. This will allow maltsters and brewers to produce better, more competitive products and will provide malting barley producers with barleys that are more competitive in the international and domestic markets.
Technical Abstract: This study was conducted to determine the number, genome location and effects of QTL determining malting quality in Harrington and Morex. Using 140 doubled haploid lines from the cross of Harrington x Morex, malting quality phenotype data sets from eight environments, and a 107-marker linkage map, QTL analyses were performed using SIM and sCIM procedures. Seventeen QTL were associated with seven grain and malting quality traits. QTL for multiple traits were coincident. The loci controlling inflorescence type (vrs1 and int-c) were coincident with QTL affecting all traits except malt extract percentage. The largest effect QTL, for percentage of plump kernels, test weight, grain protein percentage, S/T ratio, and diastatic power, were coincident with the vrs1 locus. Results suggest that this mating of two different germplasm groups caused a disruption of the balance of traits.