Determining the effect of plant growth regulators and planting density on grain yield of Adana-99 bread wheat variety under Çukurova conditions

This study was conducted in the Research and Application area of Çukurova University Faculty of Agriculture, Department of Field Crops during the 2021/2022 wheat growing season. The study aimed to investigate the effects of different planting densities (300, 500, and 700 plants/m²) and foliar applications of plant growth regulators (chlormequat chloride and Naphthaleneacetic acid) at various growth stages on the grain yield of the Adana-99 bread wheat variety. The most significant increase in grain yield (802 g/m²) was observed with NAA-40 application at a density of 300 plants/m². Meanwhile, grain yields of 769 and 760 g/m² were recorded with NAA-32 and NAA-30+KMK-32 applications, respectively, at a density of 700 plants/m². The number of grains per square meter exhibited a similar trend in the aforementioned applications for grain yield, while the effect of these applications on grain weight was found to be non-significant. This study revealed that the number of grains per square meter plays a crucial role in determining grain yield in the relationship between grain yield and yield components. This was achieved through the application of NAA during the flag leaf emergence stage. Based on these results, it is recommended that producers should apply NAA during the flag leaf emergence stage to attain higher grain yields in bread wheat.