The objective of our research was to evaluate the impact of different NPK supply levels on the lipid peroxidation in the leaf of three maize (Zea mays L.) hybrids with different genotypes and two ripening periods during the main phenophases. The extent of lipid peroxidation was performed using the method of Heath and Packer (1968), based on the amount of malondialdehyde (MDA) generated. Our measurements were performed in a polyfactoral small plot long-term fertilisation experiment, using samples taken on five occasions (4-, 6-, 8-, and 14-leaf stages, as well as silking). Examinations were performed based on a control treatment and two different fertilisation levels (Dose 1=control, Dose 2=60 kg ha-1 N 46 kg ha-1 P2O5 54 kg ha-1 K2O, Dose 3=150 kg ha-1 N 115 kg ha-1 P2O5 135 kg ha-1 K2O). The high dose of NPK fertilisation increased the extent of lipid peroxidation at the Dose 3 nutrient level. As a result of fertiliser treatments, there were significant differences between the examined hybrids, showing different values on each sampling occasion. The highest MDA level was measured in the case of H1 at the silking phase (FW: 5.01 μmol g-1 MDA). During the initial phase of development, the lowest MDA level was measured in the case of H1, which led us to conclude to the better adaptation ability of the hybrid in its early development phase. In the initial development phase, at the 4–6-leaf stage, the lowest MDA level was observed in the H3 hybrid under optimal nutrient supply conditions. In the case of appropriate nutrient supply, the MDA levels of hybrids increased during silking at the end of the growing season, but to a different extent. Altogether, during the lipid peroxidation analysis and based on the length of the growing season and the observed fertiliser reactions, the examined hybrids can be classified in order to achieve the proper adaptation abilities and the application of a proper hybrid-specific crop production practice.

Keywords: fertilisation levels, lipid peroxidation, long-term experiment, maize, NPK