The influence on wheat grain quality indices of the preliminary threshing machine parameters of
combine harvester header was investigated. The value of the trauma and the germination energy of the grain
collected by the combine with the serial and experimental harvester were determined. It was established that
as a result of passing the grain through the entire technological chain of the combine, germination energy
decreased by 1.13 - 1.15 times. For the proposed options for preliminary threshing of grain, rational
throughput values have been established, which correspond to hig h levels of germination energy. The
highest germination energy level of the grain 99% was noted in the header, the drum of which contained four
strips, according to the combine throughput 7.5 kg/s. This level was 7% higher than the serial header.