Variation in grain β-glucan due to site, cultivar and nitrogen fertiliser in Western Australia

Abstract

To adjust to projected changes in the future climate, maltsters are looking to reduce their water use. One option is to reduce the number of periods of water immersion during steeping from two to one. This might be possible if cultivars with very low grain β-glucan are used, as high β-glucan concentrations can restrict water penetration into the endosperm and the speed of germination. This study compared the grain β-glucan and various grain quality traits of nine two-row, Australian barley cultivars when grown at three sites with four rates of nitrogen (N) in Western Australia. Significant differences in grain β-glucan were found. Of the main factors, cultivar was found to have the largest effect on grain β-glucan followed by site, with N having the smallest effect. Grain β-glucan increased with increasing N application at two of the three sites. Not all cultivars responded similarly to N application. Grain with low β-glucan concentration generally had lower hectolitre weights, higher screenings, lower grain protein and was softer than grain with high grain β-glucan. There was no correlation between grain β-glucan and average grain weight, grain brightness or malt extract. The implication of these interactions and correlations in the breeding of very low grain β-glucan cultivars suited to single steep malting is discussed.