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Fyzikálně chemické změny hroznů révy vinné během zrání
Majorová, Anežka
This diploma thesis deals with the physical changes of grapevines during their ripening. Three grapevine cultivars were tested - Hibernal, Malverina and Perun. Grapes were harvested at three different times and the basic criteria for defining the level of ripeness were observed namely, in particular, the weight of bunch of grapes, the weight of ten vine berries, grape berry firmness, the percentage of dry matter and the percentage of titratable acids, and the ripeness index. The changes of all criteria in time as well as the difference between particular cultivars were observed. Furthermore, the correlation between criteria was assessed. The grape berries were also assessed from the visual point of view before harvesting. Regarding all the data which was collected, the decrease of titratable acids for each grapevine cultivar was proven during the monitored period. For Hibernal, a linear decrease of 26mg/100g per day was observed. Linear decrease was also observed for grape berry firmness of 18 kPa in case of Hibernal, and 24 kPa in case of Malverina. Increase of the percentage of dry matter was observed for all three cultivars. In addition, a correlation between the weight of a grape berry and any other measured criteria was not found. The ripeness index shows a different beginning of ripening of different cultivars.
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Vliv regulace násady hroznů na vývoj révy a kvalitu hroznů
Ťápal, Marek
The knowledge of location conditions, grapevine morphology and physiology are the fundamental assumptions for production of high quality grapes and final wine. The quality management should be considered as a comprehensive set of agrotechnical steps which influence the crop quality. The canopy management, especially bunch thinning, represents a group of actions influencing grapes quality parameters such as sugar and acids content, pH value and the content of polyphenols, anthocyanins and yeast assimilable nitrogen. The aromatic or phenolic maturity and plant vigor are influenced by the canopy management, too. The bunch thinning experiment with Malverina grape variety showed a very positive effect on sugar and acids content, pH value, aromatic maturity and plant vigor.
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