GENETIC DIVERSITY IN MALT QUALITY OF NORTH-AMERICAN 6-ROWED SPRING BARLEY

Malting barley (Hordeum vulgare L.) breeders often are accused of using germplasm with a narrow genetic base for development of new cultivars. Yet, gains are being made in improving agronomic and malt quality traits. This suggests that more variability exists than otherwise can be expected by examining pedigrees. The objective of this study was to compare results from the cluster analysis based on the coefficients of parentage between 21 North American six-rowed barley cultivars with the cluster analysis based on 10 malt quality traits of the same cultivars. This information may aid us in determining if further gains can be expected by intercrossing closely related genotypes, and to identify those malt quality traits in which improvement can be expected. Malt quality traits evaluated were kernel plumpness, grain protein, hue-grind extract, coarse-grind extract, fine-coarse extract difference, soluble protein, soluble protein to total barley protein ratio, diastatic power, alpha-amylase activity, alkaline viscosity, and total malt beta-glucan content. Data on these traits for each of the 21 cultivars were collected on malt produced from samples of grain grown at Fargo, ND, over 3 yr. Composition of the clusters based on the coefficients of parentage was different from that of the clusters based on the analysis of malt quality traits. Clusters based on the analysis of the coefficients of parentage were related to the location of develop ment of the cultivars. Results suggest that gains in malting quality still may be expected from intercrossing germplasm from different breeding programs and even within a program. Traits that may be improved further are kernel plumpness, diastatic power, alpha-amylase activity, soluble to total protein ratio, alkaline viscosity, and total malt beta-glucan.