In this study, three black currant cultivars (Ben Sarek, Ben Lomond and Malling Juel) and three red currant cultivars (Industrija, Rondom and Red Versailles) were compared in terms of fruit quality by high-performance liquid chromatography analysis in order to determine sugars and organic acids profiles in their fruits. Among the analyzed individual sugars, fructose was determined to be the major component in all studied cultivars.

The effects of foliar application of paclobutrasol (PK), chlorcholinechloride (CC) and gibberellic acid (GA₃) on grape yield and quality of the grapevine cultivar Limberger were studied. PK and CC strongly inhibited shoot growth. The number of berries per bunch, bunch weight and grape yield per m² were increased. At the same time, sugar content of must was either reduced (CC2000) or retained at the level of control (PK1000, CC1000). The GA150 treatment resulted in lower grape yield.

Partial root drying (PRD) is a new irrigation and plant growing technique which improves water use efficiency without significant yield reduction. The aim of the presented thesis was to investigate the effect of this technique on the growth of vegetative and generative tomato organs, and especially fruits, its influence on the activity of enzyme cell wall peroxidase morpho-anatomical characteristics of flower and fruit pedicels, influence on fruits yield and quality and ions distribution in tomato organs.