Determination of the effect of sowing time and nitrogen amount on grain yield in Gökhan bread wheat variety

This study was conducted at the Research and Application area of the Department of Field Crops, Faculty of Agriculture, Çukurova University, during the 2022/2023 growing season. The objective was to evaluate the effects of four sowing dates (November 20, December 12, January 3, and January 23) and five nitrogen application rates (0, 5, 10, 15, and 20 kg N da⁻¹) on the grain yield of the Gökhan bread wheat variety, using a split-plot design with three replications. Sowing date served as the main plot factor, while nitrogen dosage was assigned to the sub-plots. The results indicated that both sowing dates and nitrogen doses significantly influenced spike stem length, spike length, plant and spike density per square meter, grain yield, grain weight, harvest index, hectoliter weight, and the protein and starch content of the grain. A significant negative correlation was observed between grain yield and traits such as plant height, spike stem length, spike length, grain count per square meter, and grain protein and starch content. In contrast, positive correlations were identified between grain yield and grain weight, biological yield, harvest index, and hectoliter weight. The highest grain yield for the Gökhan bread wheat variety under the conditions of Çukurova was achieved with the sowing on January 23. These findings suggest that the typical sowing period, which usually begins in the second half of November, can be extended until the last week of January. Keywords: Bread wheat, planting time, nitrogen dose, grain yield.