Determination of critical nitrogen concentration of canola leaf and study of correlation between yield, yield components and chlorophyll index with leaf nitrogen concentration

In order to determine the critical nitrogen concentration of canola leaf and studying the correlation of yield and yield components of this plant with leaf nitrogen concentration, 35 farms were managed in the same way of Varamin plain and in the dominant soil serie (Varamin), were selected during 2016. Leaf samples were pick up from these farms at flowering stage and were prepared for analysis. In harvest season, all 35 fields were harvested and the mean grain yield was determined. The critical nitrogen concentration in dry leaves was determined at 3% by using Kate and Nelson's graphical method, for 90% relative yield. There was a significant correlation between the content of canola leaf nitrogen as independent variable (X) with other traits, including grain yield and yield components as dependent variables (Y) at the 35 studied farms. The results of the studies showed that canola seed yield was affected by leaf nitrogen content. The content of nitrogen in canola leaves was significantly correlated with grain yield. This correlation was followed by a quadratic function with a coefficient of explanation of 0.97. Relative yield of canola seed increased only to 4.36% nitrogen concentration of leaves, and since then, the increase in leaf nitrogen did not affect grain yield.