Comparison of the reactions of new native bread wheat (Triticum aestivum L.) varieties to different seed densties and nitrogen doses

To examine the effects of different nitrogen dose applications and sowing densities on the grain yield and quality characteristics of bread wheat under Tekirdağ ecological conditions, 4 new bread wheat cultivars (NKÜ Lider, NKÜ Ergene, NKÜ Asia and NKÜ Zirve) developed by TNKU Faculty of Agriculture, Department of Field Crops were used as the genetic material in the study. The field experiment was divided in random blocks to form 4 different sowing densities (300, 400, 500, 600 seeds m-2) sub plots and 4 different nitrogen doses (12, 16, 20 and 24 kg da-1) sub-sub plots for each variety. The split-split plots experimental design was carried out in 3 replications in the 2020-2021 growing period. The grain yield and some yield components and grain quality characteristics were examined in the study. As a result of variance analysis, it was determined that the effects of cultivars, different plant density and nitrogen dose applications on most yield and quality characters were significant in the study. For the bread wheat varieties used in the research, it was seen that increasing the seed amount, although not regularly, was successful in increasing the grain yield up to a certain point, despite the decreases in other grain yield and yield components except plant height. However, it was determined that there was a decrease in quality characteristics in the same situation. In addition, it has been understood that the increased nitrogen dose also causes increases, although not regularly. It can also be stated that these effects on yield and quality characteristics differ for each variety. It was concluded that the combination of 400 seeds m-2 sowing frequency and 20 kg da-1 nitrogen dose for high grain yield, and the most appropriate sowing frequency for grain quality, 400 seeds m-2 and 24 kg da-1 nitrogen dose combination may be the most appropriate. Keywords: Bread Wheat, Nitrogen Fertilization, Sowing Density, Grain Yield, Yield Components, Protein Ratio