Growth dynamics and yield of winter wheat varieties grown at diverse nitrogen levels
The growth dynamics determining the yield of winter wheat depends partly on genetic determination and partly on environmental factors, including nutrient supplies. Growth and yield responses to nutrient supplies were investigated for three diverse genotypes. In the dry year of 2007 dry matter production and leaf area were influenced chiefly by N supplies, while in the more favourable year of 2008 the genotypic effect was more pronounced, and in most cases N fertiliser only led to a significant increase in yield up to a rate of 80 kg ha −1 . The maximum value of the leaf area index (LAI) was recorded at the 240 kg ha −1 N level for all three varieties in 2007 (11.5; 9.9; 8.1), while in 2008 the maximum was observed at the 160 kg ha −1 N level for Mv Toborzó and Mv Palotás (8.6 and 8.4, respectively), and only in Mv Verbunkos did LAI continue to increase up to 240 kg ha −1 N (9.8). The cumulative BMD and LAD parameters mostly exhibited much higher values in 2007 than in 2008. The maximum grain yield was achieved at 160 kg ha −1 N in 2007 and at 80 kg ha −1 N in 2008. It could be concluded from the results that the manifestation of genotypic traits was enhanced by favourable weather conditions, which also led to the better utilisation of lower rates of N fertiliser.