AbstractUptake and distribution of nitrogen in old and new German summer wheatsFive old German summer wheat varieties, bred in the first third of this century, were compared with five new varieties in an outdoor pot trial. The modern genotypes had taken up slightly more N, both at anthesis and at maturity. At anthesis, N percentage in all organs was considerably higher for modern cultivars. This resulted mainly from a dilution effect caused by superior dry masses of old varieties. Modern genotypes accumulated more N in the upper leaves and ears. As compared with the old varieties, less N was found in the stems of the new cultivars. At maturity, N concentration in vegetative organs was simular for both groups of varieties. N percentage of grains was higher for old cultivars. However, the new genotypes achieved higher N yields. This resulted in part from the slightly higher assimilation of N. Moreover, new genotypes were superior in N translocation which was reflected by higher nitrogen harvest indexes. The postfloral loss of N from the vegetative tissue depended on the organ and the age of the varieties.