Exponential Model Parameters Evaluation Of Dry Matter And Nitrogen Accumulation Trends In Grain Of Spring Wheat Genotypes Using Linear Regression Method

In order to evaluate exponential model parameters of dry matter and nitrogen accumulation in grain of spring wheat genotypes, this study was conducted in Ahvaz Research Station in 1998-99 cropping season. Dry matter and nitrogen accumulation trends were studied in two seprated experiments. In the first experiment, irrigation was carried out normally until physiological maturity, while in the second experiment, the last irrigation was done one week before anthesis to make post - anthesis drought stress. Results showed that exponential model Y = A/ 1 + exp [ ? - DAA)/?] properly explained dry matter and nitrogen accumulation sigmoied trends. Cosidering the high significant correlation of A prameter with dry matter or nitrogen accumulated in physiological maturity, the model was determined as mathematical formula Y = Ym/ 1 + exp [(?- DAA) / ?] . Using canonic correlation results and multivariate statistical analysis and refer to high correlation of ? parameter with effective filling period (EFP) and calculation method of : EFP = Ym / b in which b is the regression slope in gpain linear growth period, parameter ? and also ? will be easily eveluated by determining Ym and b. High significant correlation of actual and estimated data from the above mentioned model and also high determination coefficient oflinear regression based on estimated data(Yest.) and actual dala (Yact.), showed minimum error for model parameter calculation and unbaised evaluation from this introducied method for determination of grain dry matter and nitrogen accumulation in studied genotypes and every sigmoied trends.