EN
The experiment was carried out in three localities: Łagiewniki, Zielecin, Małyszyn. The subject of the study was an open-pollinated cultivar – Casoar and a hybrid cultivar – Visby. Seeding rate of open-pollinated and hybrid cultivars amounted to 40, 80 and 35, 70 seeds/m2. Two spring nitrogen fertilization levels 160 and 220 kg N/ha and three plant protection programs were applied. The most intensive protection comprised fungicide application in the stage of 4–6 leaves, stem elongation and flowering. Less intensive programs of protection consisted fungicide application in the stage of 4–6 leaves and flowering or in the stage of stem elongation and flowering. All experimental factors significantly influenced the yield of seeds but the highest effect on the yield had environmental conditions and cultivar. Higher yield was recorded for cultivar Visby, nitrogen dose of 220 kg/ha, seeding rate of 70 seeds/m2 for hybrid cultivar and 80 seeds/m2 for openpollinated cultivar and plant protection which comprised fungicide application three times in the vegetation season. The increase of production intensity caused higher profitability of winter oilseed rape growing.