Two experiment series differing with the quality of the seeding material used for the study were performed in 1986–1998. In series I, the seeding material (superelite – control) was every year purchased from the farmer. In series II, the same seeding material at superelite class from 1996 harvest is stored in the Polish Center of Plant Genetic Resources IHAR, Radzików, was used each year. The results, in both experimental series, point out to a lack of significant differences referring to grain yield between superelite and subsequent reproductions. Values of yield structure elements remained at similar levels in subsequent reproductions.