Control through breeding methods of factors affecting nutritional quality of cereals and grain legumes

The comparison of nutritional quality parameters of proteins from cultivated cereal and legume species with animal proteins indicate the poor nutritional value of these plant products. The nutritive value of different cereal and legume species is very variable and large differences have also been observed coming from cultivars belonging to the same species. Many interpreting factors, such as protein content, essential amino acid composition and availability, protein digestibility and others are involved in such a highly variability. In addition, cereals as well as legumes may contain large amounts of antinutritional factors which can have serious effects under particular circumstances (e.e. tannins in a low-protein diet or phytates in a metal-deficient diet). Some legume species also contain chemicals of a different nature (i. e. lathyrogens, cyanogenetic glycosides, and others) which may be extremely toxic when ingested in significant amounts. The plant breeder attempting to develop higher-yielding, disease-resistant and nutritionally-improved crop varieties should be aware of such a complex of factors and alert to the possible production or increase of undesirable products or deleterious changes in chemical composition. Available data, although rather limited, indicate valuable breeding approaches to the improvement of nutritive value of cereal and legume grains for humans.