The post-harvest germination and the germinative ability one year after harvest, as well as the vigour of eight Pioneer maize hybrids were examined in four sowing seed laboratories. The genetic purity was checked in laboratory conditions and at a test production station. Experimental plot sections were separated on the test production plots and half of these sections were combine harvested, while the other half was ear harvested. The objective was to determine whether the quality parameters of maize sowing seed (germinative ability, vigour, genetic purity) will be deteriorated in the case of shelled harvesting. The germination of sowing seeds was done untreated in four sowing seed examination laboratories in accordance with the ISTA standard and their vigour was examined in one laboratory. Two randomly selected hybrids were divided into four fractions and each fraction was analysed separately. All germinative ability results were in accordance with the standards (above 90%). The germination results of the shelled sowing seed maize did not reach that of the maize of which the entire ear was harvested, while the number of abnormal seedlings was higher in the case of the experimental (combine harvested) maize than the other group. During the germination of the fractional sowing seed lots, the lowest germinative ability was shown by the round medium fraction, while the highest value was obtained in the case of the large plain fraction. During the vigour analysis, certain hybrids from the shelled group provided better results, probably due to stress during the processing or drying of the ear group. The sowing seed samples were stored in the sowing seed plant of Pioneer Hi-Bred Plc. and they were examined again one year after harvesting. During the evaluation of the one-year germination results, it was established that all hybrids showed reduced germinative ability but they stayed withing standards. No significant difference was observed between the two harvesting methods and no significant difference was shown in vigour either. The genetic purity was examined with Isoelectric Focusing (IEF) and test production. During the test production, the ear harvesting had better results than the shelled harvesting. As regards the IEF method, the result was not so straightforward, as the shelled harvesting showed better values in certain cases. It can be established from the IEF examination that the ratio of invasive plants pollinated by other invasive plants was higher than that of the self-pollinated ones. After continuing the series of experiments, it could be considered to perform combine harvesting of the hybrid maize sowing seed in certain cases.

Keywords: maize seed, germinative ability, vigour, genetic purity