Qualidade e capacidade antioxidante durante a maturação da uva BRS Magna em função de porta-enxertos nas condições tropicais do submédio do vale do são francisco

Abstract

The diversification of vitiviniculture for juice production in the Submedium region of São Francisco Valley, especially from the increase on the cultivation of Vitis labrusca and hybrid grapes, suggests a need for research focused on the study of components of the productive system and its influence on fruit and their derivatives. The objective of this study was to characterize changes in compounds determining the quality of 'BRS Magna' grape during maturation from plants growing on different rootstocks, during production cycles of the first and second half of the year. The experiments were carried out in the Experimental Field of Bebedouro, Embrapa Semiárido, Pernambuco State, Brazil, with vines of BRS Magna cultivar, on overhead trellis system and drip irrigation system. Four production cycles were evaluated, with two production cycles of the first and second semester of 2017 and 2018. The treatments combination corresponded to ‘IAC 313’, ‘IAC 572’, ‘IAC 766’, ‘Paulsen 1103’, ‘Harmony’ and ‘Freedom’ rootstocks and fruit age (related to maturity stages). The clusters were periodically collected from véraison to harvest. The experimental design was in randomized blocks, in subdivided plots through time, for each production cycle studied. The rootstocks were distributed in the plots and the dates or fruit age in the subplots. Four replicates were used, with six plants each, from which five bunches were collected, in each time. In the study comparing the two production cycles of the first semester, the 2018 cycle, in a general view, favored a greater accumulation of flavonoids and anthocyanins in skins. In both cycles of the first half, the harvest at approximately 64 DAF (days after fruit set) potencialized the quality. Higher levels of anthocyanins and yellow flavonoids were favored by 'IAC 313' and 'IAC 572' rootstocks in the 2017 cycle, as well as 'IAC 313' and 'IAC 766' in the 2018 cycle. In the stydy comparing both cycles of second semester, the cycle of 2017 favored the 4 anthocyanins accumulation in skin berries, being 'IAC 766' which resulted in higher contents. Regardless of the method for free radical capture adopted, the 'IAC 572' rootstock promoted greater antioxidant capacity to the grapes. Using multivariate analysis tools to study the data of four successive production cycles was possible to confirm that grapes with more advanced maturation presented higher contents of bioactive compounds that reflected the higher antioxidant capacity. By these procedures, it was also concluded that the rootstocks 'IAC 572' and 'Freedom' stood out for gathering the best quality characteristics in specific crops.