Drawing on the statistical survey performed over 2010-2011 on 155 farms in the Kujawy and Pomorze region, there was evaluated cultivar diversity for basic field crops and it was compared in the sown crops of winter wheat, spring barley, winter triticale, rye, maize, winter rape, sugar beet and potato. The following were determined: the knowledge of crop cultivars sown by farmers on production plantations and the most frequently grown cultivars, their number to the number of plantations of that species, diversity and domination defined using the Shannon-Wiener and Simpson indices. It was found that on 15.8-43.4% plantations the cultivars were not known to the farmers, most in the sown crops of spring barley. The best knowledge was recorded for the cultivars of winter wheat, winter rape and potato. A high richness of cultivars, expressed with the number of cultivars to the number of plantations, concerned the crops of potato, sugar beet and maize and the lowest richness - rye. The highest cultivar diversity of crops occurred in the sown winter wheat, winter triticale, winter rape, corn and spring barley. The lowest diversity, however, at the same time, the highest cultivar dominance, was recorded for sugar beet, potato and rye. The highest share of a single cultivar in the sown crop of the species was reported for 'Californium' winter rape, 'Dankowskie Zote' rye and 'Lord' potato.
