Corn cultivation is an important component of the grain industryin any agricultural country. Corn is characterized by its versatility and high yield. One of the most important prerequisites for obtaining high yields is planting with high-quality seed material. Similarity is the main indicator of seed quality. The formation of similarity depends on a number of factors that affect the plant and grain during ripening. These factors include the dynamics of moisture release and accumulation of dry matter, as well as the moisture content at which the seeds are harvested. During the research, features the ripening of corn hybrids were established and the humidity at which seed germination was formed was determined. It was established that at a moisture content of 50–51%, the grain contains 71–83% of the maximum possible dry matter. The maximum content was recorded at a humidity of 30–33%. Laboratory similarity wasformed at a moisture content of 47.2–53.5% and below, depending on the hybrids. It was found that seed moisture release compared to previous multi-year data has significantly increased, ranging from 0.8–2.3% per daydepending on the hybrids. The accumulation of the main mass of dry matter is completed at a moisture content of 22–30%. At a moisture content of 32–40%, the seeds already reach high field similarity and productivity depending on the maturity group of the hybrids.