Breeding for malt and feed quality in northern Australia

Abstract

Most countries that produce barley classify their varieties as either malt or feed with the feed class consisting of varieties that are not biochemically suited for malting. However, these varieties have probably not been tested for any animal feed value. In a number of countries, including Australia, more barley is used annually for feeding animals than used in beer production. Under Australian feedlot conditions, anecdotal data had suggested that malt varieties were best for feeding cattle but little data was available to support this generalisation. We have undertaken a study comparing over 30 Australian varieties and breeding lines to ascertain some scientific basis to this theory. Genotypes from two sites and two years replicated trials were evaluated for malt and feed analysis. Results indicated that the levels of resting grain components were similar for each end-use. There was no apparent difference in total starch content between malt and feed. However, there were differences for the in sacco Dry Matter Digestibility with the good feed and malt genotypes having low levels. While there was no strong relationship for particle size (hardness) between malt and feed quality there was a relationship within a genotype with feed type being slightly harder. This relationship was independent of protein content. The most significant area of difference is the need for malt varieties to produce moderate to high levels of enzymes to breakdown endosperm components during malting and mashing. Varieties that performed especially well in both end-uses, ie. good malt quality and improved animal performance, were current malting varieties. The biochemical results to date demonstrate that breeding programs could effectively select for improved malt and feed quality in breeding lines by focusing on malt quality and selecting lines with high level of enzymes