Four varieties of potatoes were cultivated for 2 years in a blend of varieties and also separately with and without application of fungicides against potato blight. The cultivation of varieties in a blend gave higher yield of tubers and starch as well as higher starch content in tubers than for separately cultivated varieties. The cultivation in a blend had no effect on starch properties. The use of fungicides increased tuber and starch yields and starch content in the tubers relative to cultivation without fungicides. The application of fungicides decreased viscosity of starch pastes.