DETERMINATION OF NITROGEN UTILISATION AND NITROGEN UPTAKE EFFICIENCY OF SOME WHEAT GENOTYPES UNDER LIMITED NITROGEN CONDITIONS

Wheat is one of the most important human foods in Turkey and the most important nutrient of wheat plant is nitrogen. Since the green revolution in wheat variety breeding, high nitrogen high yielding varieties have been bred. Nitrogen resources of our world are limited, the use of excess nitrogen fertilisers for years has caused environmental pollution. It is also one of the important costs in wheat farming. There is a need to breed new wheat varieties that will reduce the use of nitrogen fertiliser. In order to reduce the damage to the environment and economic damage to the producer, it is important to breed high yielding varieties that require less nitrogen fertiliser. Otherwise, the cost of nitrogen fertiliser and the depletion of its reserve will negatively affect wheat production. A total of 7 genotypes including 4 local bread wheat genotypes, 2 durum wheat varieties (svevo, fırat93), 1 local siyez wheat collected from the villages of the Southeastern Anatolia region which is the homeland of wheat plant were used. The experiment was established according to split-plot design with 4 nitrogen doses and four replications. Nitrogen uptake efficiency and nitrogen utilisation efficiency were inversely proportional to nitrogen dose and nitrogen uptake efficiency increased as nitrogen dose decreased. Increasing nitrogen doses had an inverse effect on nitrogen uptake efficiency and the nitrogen dose with the highest nitrogen uptake efficiency was in the lowest nitrogen dose application. The genotype with the highest value among the local genotypes was GYE4.