Multiple regression analyze the relationship between crop size of cereals (winter wheat, winter rye) and weather conditions, verified with the cross validation test

Abstract: This analysis examined the impact of the weather conditions (sums of effective temperatures and total precipitation) prevailing during a particular period of plant development on crop sizes of cereals (winter wheat, winter rye). The relationships were analyzed based on data obtained from COBOR research stations (Polish Center for Crop Varieties Evaluation) and from nearby meteorological stations. After an initial evaluation, the equations of multiple regression were verified with the Cross Validation test. Conclusions on the existing relationships were drawn based on the models which were positively verified. The data from some localizations did not provide a basis for any positively verified model of regression. But, on the other places, the increase in wheat and rye crop size was correctly described by an equation with a variable duration of the period from shooting to heading. The yield also proved to be dependent to a statistically significant degree on atmospheric precipitation during the period of waxy maturity – harvest and the total precipitation of the phase of emergence – tillering. An increase in these parameters caused a reduction in the crop size. In this locations, a statistical relationship appeared between the time of emergence and the yield of wheat.