effect of genotype variability on nitrate uptake and assimilation of wheat cultivars

nitrate concentration of the soil, at the start of growing season, is high due to minerali-zation of soil organic n during the fall and the addition of n fertilizers. it may be useful to exploit this n form as much as possible. therefore, the nitrate uptake, assimilation and dry matter production of several wheat cultivars were examined in a series of experiments using a hydroponic culture system. seedlings were grown at two rates of nitrates (0 and 1.0 mm) and the experiments lasted for 26 days. significant genetic variation in the growth and nitrate uptake were observed. the atila and yavarous cultivars consistently produced large seedlings absorbing higher quantities of nitrate from the nutrient solution, compared to the falat, star and seri 11 cultivars which produced smaller seedling and took up lower amounts of nitrate. however, apart from seedling vigor, there was evidence that some cultivars were more efficient physiologically in assimilating nitrate. for compa-rable amounts of nitrate taken up from solution, total dry matter production in this group of cultivars was considerably greater than others. results of this work revealed that ge-netic differences among wheat cultivars affect nitrate uptake, which in turn indicated the influence of plant status and in particular root system on the potential of nitrate uptake.