ABSTRACT. Environmental and production factors might affect grapevine physiology. Estimating these effects is essential for planning the harvest and predicting the quality of grapes. The aim of this study was to characterize the quality and antioxidant potential of ‘BRS Cora’ grapes with different training systems and rootstocks in production cycles of the second half of the year under tropical conditions. The experimental design was randomized blocks with sub-subdivided plots over time. Three training systems and two rootstocks were studied in production cycles referring to the second halves of 2017 and 2018. In 2017, the grapes of plants trained with lyre and vertical shoot positioning (VSP) had the highest soluble solids and sugars contents, and in 2018, this response occurred with the overhead trellis system. There was lower variation in titratable acidity between cycles of grapevines trained with VSP and lyre, as well as in those grafted onto ‘IAC 572’. In 2018, lyre with ‘IAC 572’ promoted higher pigment accumulation. Climatic conditions in 2017 provided a higher accumulation of polyphenols and antioxidant activity in grapes of plants trained with lyre with ‘IAC 766’. The efficiency of the training system within each cycle, associated with the effect of the rootstock, resulted in differentiated responses according to climatic conditions.

ABSTRACT The quality and phenolic compound composition might be affected by production system due to microclimate around the bunches and sunlight interception provided by vegetative canopy architecture and environmental conditions. The aim of this study was to characterize the quality and antioxidant potential of ‘BRS Cora’ grapes with different trellis systems and rootstocks in rainy seasons under tropical conditions. Three trellis systems and two rootstocks were studied in production cycles during the first halves of 2017 and 2018, using a randomized-block experimental design. Interactions between the trellis systems,rootstocks and cycles differentially affect the fruit quality. The association between vertical shoot positioning or an overhead trellis with ‘IAC 766’ induced higher polyphenol compound contents. In turn, the trellis systems overhead trellis and lyre provided greater stability for the berry weight, soluble solids, total soluble sugar contents, yellow flavonoids, total extractable polyphenol compounds or antioxidant activity in both production cycles. The results of this study inferred that the grape quality and phenolic compound composition were not only affected by some specific climatic factors but also by the trellis system, rootstock, and the interaction between the three factors.

RESUMO A videira ‘BRS Magna’ tem como vantagens a adaptação a diferentes regiões brasileiras e a elaboração de suco de qualidade. Entretanto, requer a definição de componentes do sistema de cultivo, como porta-enxerto, para cada região. O objetivo deste estudo foi caracterizar a composição química e o potencial antioxidante de sucos de uvas colhidas de videiras ‘BRS Magna’ cultivadas sobre diferentes porta-enxertos, nas condições tropicais do Submédio do Vale do São Francisco. As uvas foram colhidas no Campo Experimental de Bebedouro/Embrapa Semiárido, em Petrolina-PE, Brasil. Os tratamentos corresponderam aos porta-enxertos ‘IAC 766’, ‘IAC 572’, ‘IAC 313’, ‘Freedom’, ‘Paulsen 1103’, ‘Harmony’ e ‘SO4’. Foram elaborados os sucos de uvas de duas safras, para avaliação após o armazenamento. Para cada safra, adotou-se o delineamento experimental em blocos ao acaso, com quatro repetições. A qualidade dos sucos variou com os tratamentos, em cada duração do armazenamento. Aos nove meses, os sucos da primeira safra apresentaram perda de pigmentos e de compostos fenólicos, sendo que aquele elaborado com uvas de plantas enxertadas sobre ‘Harmony’ distinguiu-se pelos teores de sólidos solúveis (SS), intensidade de cor (IC), antocianinas, índice de polifenois totais (IPT) e capacidade antioxidante. Os sucos da segunda safra, aos quatro meses, caracterizaram-se por maiores teores de alguns compostos, destacando-se o tratamento ‘SO4’ pelos SS, IC, polifenóis extraíveis totais, IPT e capacidade antioxidante. Os porta-enxertos menos vigorosos conferiram melhor qualidade ao suco, desde que se considere o potencial de armazenamento e o processo de elaboração.

ABSTRACT The ‘BRS Magna’ grapevine has the advantage of adapting to different regions of Brazil and producing juice of good quality. However, it is necessary to define the components of the cropping system, such as the rootstock, for each region. The aim of this study was to characterise the chemical composition and antioxidant capacity of grape juice collected from ‘BRS Magna’ grapevines grown on different rootstock under the tropical conditions of the Sub-middle São Francisco Valley. The grapes were harvested in the Experimental Area of Bebedouro/Embrapa Semiárido, in Petrolina, Pernambuco, Brazil. The treatments corresponded to the ‘IAC 766’, ‘IAC 572’, ‘IAC 313’, ‘Freedom’, ‘Paulsen 1103’, ‘Harmony’ and ‘SO4’ rootstock. The grape juice was prepared from two harvests for evaluation after storage. For each harvest, a randomised block design was used, with four replications. The quality of the juice varied with the treatment in each storage period. At nine months, the juice from the first harvest showed a loss of pigment and phenolic compounds, while the juice made with grapes from plants grafted onto ‘Harmony’ stood out for soluble solids content (SS), colour intensity (CI), anthocyanins, total polyphenol index (TPI) and antioxidant capacity. Juice from the second harvest was characterised at four months by higher levels of various compounds, especially the ‘SO4’ treatment for SS, CI, total extractable polyphenols, TPI and antioxidant capacity. Considering storage potential and the preparation process, the less-vigorous rootstock resulted in better quality juice.

RESUMO O Submédio do Vale do São Francisco é reconhecido pela particularidade das condições de produção de uvas para diferentes usos. A produção de uvas para suco nesta região é relativamente recente. Por isso, o conhecimento acerca dos componentes do sistema produtivo ainda é limitado. O objetivo deste trabalho foi caracterizar a qualidade e a atividade antioxidante da uva ‘BRS Magna’ sob influência de sistemas de condução e porta-enxertos, em ciclos produtivos do primeiro semestre do ano, em cultivo irrigado no Submédio do Vale do São Francisco. O experimento foi conduzido no Campo Experimental de Bebedouro/Embrapa Semiárido, em Petrolina, Pernambuco, Brasil. Foram estudados os sistemas de condução latada, lira e espaldeira e os porta-enxertos ‘IAC 572’ e ‘IAC 766’, nos ciclos produtivos correspondentes ao primeiro semestre dos anos de 2017 e 2018. O delineamento experimental foi em blocos ao acaso em parcelas subsubdivididas no tempo com quatro repetições. No geral, as respostas foram dependentes do sistema de condução, porta-enxerto e ciclo de produção, que determinaram características específicas às uvas. A produção no primeiro semestre de 2018 caracterizou-se por elevados teores de antocianinas e de polifenóis extraíveis totais e atividade antioxidante superior, sendo as respostas diferenciadas conforme o sistema de condução e o porta-enxerto. Plantas conduzidas em latada e enxertadas sobre ‘IAC 572’ tiveram maior acúmulo de polifenóis extraíveis totais e atividade antioxidante nas bagas. Sob espaldeira, foram observados incrementos nos teores de açúcares, flavonoides amarelos e antocianinas das bagas enquanto o sistema lira promoveu maior massa dos cachos.

ABSTRACT The Submedium São Francisco Valley is renowned for its particular conditions for cultivating grapes for different uses. The production of grapes for juice is relatively recent, and thus, knowledge is still limited on components of the production system. The aim of this study was to characterize the quality and antioxidant activity of ‘BRS Magna’ grapes in irrigated crops of the Submedium São Francisco River Valley under the influence of training systems and rootstocks, in production cycles of the first half of the year. The experiment was conducted in the Experimental Field of Bebedouro/Embrapa Semiárido, in Petrolina, Pernambuco, Brazil. The following were studied: overhead trellis, lyre, and vertical shoot positioning (VSP) systems and rootstocks ‘IAC 572’ and ‘IAC 766’, in the production cycles corresponding to the first halves of 2017 and 2018. Experimental design was in randomized blocks, with sub-subplots through time and four replicates. Overall, responses depended on training systems, rootstocks, and production cycles, which determined specific traits of the grapes. Production in the first half of 2018 was characterized by high anthocyanin contents, high total extractable polyphenols, and higher antioxidant activity, and responses were differentiated according to training system and rootstock. Plants trained to overhead trellis and grafted on ‘IAC 572’ had higher accumulation of total extractable polyphenols and antioxidant activity in berries. Plants trained to VSP had increased sugar, yellow flavonoid, and anthocyanin contents in berries while lyre training system led to higher bunch mass.