Adjusting yield components under different levels of N applications in winter wheat

This work presents information on the patterns of yield determination by yield components as a function of the level of management of the crop. The data used for the analyses were obtained from 8 field experiments located across Poland in 2009 and 2010. 25 winter wheat cultivars were evaluated at two management levels, i.e., at a low input of nitrogen fertilisation and pesticides and at a higher input of these materials. Yield determination was evaluated with a path analysis conducted for each cultivar separately for each management level. The results were presented using the values of the path coefficients. The pattern of yield determination for most of the cultivars examined differed between the high-input and the low-input management levels. Under the low-input management, all three yield components contributed similarly to yield determination. Under high-input management, the effect of the number of spikes per m 2 was much greater than the effect of the weight of an individual grain.