The aim of this diploma thesis is the identification of yeasts isolated during grape must fermentation. The must was obtained from Pinot Noir varieties grown in an integrated and organic production. The partner of this thesis was a winery Holánek. In the theoretical part of the work was the emphasis on information about the determinants quality of wine, yeasts and PCR-RFLP method. Physiological properties of yeasts were described and also the principles of the polymerase chain reaction (PCR) were explained. In the experimental part of the thesis was applied molecular biology method PCR-RFLP for identification of yeasts. The specific segment of DNA was amplified (5, 8S-ITS rDNA sequencing) with the help of ITS1 and ITS4 primers. The incurred amplicons were digested by applying restriction endonucleases: HaeIII, HinfI and TaqI. Subsequently the restriction fragments were analysed by using of electrophoresis. The yeasts were identified and classified by taxonomy on the level of genera and species
