Composition of variety mixtures in barley and wheat

Summary

Breeding within the last 50 years has focused on developing genetic uniform crops/varieties for farmers to be able to produce homogeneous products to be sold. Therefore, especially for selfing crops like wheat and barley where nearly all plants in a field are genetical identical, specific tools have to be applied to ensure genetic diversity. Among these tools is the use of variety mixtures. Principles for composing variety mixtures are to a large extent based on disease resistance characteristics and this is insufficient to predict the performance of the mixtures. Biological principles for interactions between varieties will be of relevance not only to organic farming but also to conventional agriculture where variety mixtures have been used for many years to a varying degree. To improve the performance of mixtures especially under organic conditions we need more information on the ability of different varieties to complement and compensate for each other under a range of different conditions (specific and general mixing ability).