Barleys grown as cultivar mixtures compared with blends made before and after malting, for effects on malting performance

Four barley cultivars were grown in replicated trials at three sites in Scotland in 2000, both as pure stands and in all four possible three-component mixtures. After harvest, some grain from the pure stands was used to synthesise four blends of three component varieties. Grain from the pure stands, the mixtures and the blends was malted and all samples were assessed for total beta-glucan content. At two of the sites, field grown mixtures were shown to have lower malt beta-glucan than blends made prior to malting, although their grain beta-glucan contents had not been significantly different from the means of the component varieties. At the other site, the mixtures had higher levels of soluble nitrogen than the blends or the means of their component cultivars although, significant differences had not occurred in grain nitrogen contents. Three component blends were also made from the malted grain of the pure stands and hot water extracts were measured on all samples including the blends made before and after malting. There were considerable differences between sites and also between mixtures, blends and the mean of the mixture components when assessed separately. At all sites and for all varietal combinations, field grown mixtures were shown to be equal or superior to blends made after harvesting, in addition to frequently exceeding the mean of their components. It was concluded that the advantages, in beta-glucan or protein modification, associated with mixtures resulted from interactions between components in the growing environment and that interactions in the malting and mashing environments had little if any effect.