To this day plant breeding is most successfully carried out empirically by crossing promising lines with each other and by selecting high yielding plants with improved quality. Biochemical genetics provides increasing possibilities to determine the metabolic pathways leading to storage proteins, enzymes, flavonoids and fatty acids, compounds which give favourable or unfavourable quality characteristics to the desired plant product. Mutations blocking the pathway are of special significance in evaluating the effect of a substance on a quality parameter. Molecular genetics permits the isolation of individual genes and their multiplication in bacteria and yeast. The structures and expression of genes in single copy and complex loci can thereby be explored. The information obtained provides the basis for breeding strategies. In spite of knowledge about the biochemical pathways and the structures of the genes, the selection of the appropriate rare genotypes is often economically unfeasible. Genetic transformation and the application of fluorescent monoclonal antibodies in a non‐destructive way are methods of choice to overcome these restrictions. These problems and their solutions are examplified by breeding of proanthocyanidin‐free malting barley and breeding for improved nutritional quality of feeding barley.