Production Parameters and Biochemical Composition of ‘BRS Núbia’ Table Grapes Affected by Rootstocks Under Subtropical Conditions

Table grapes are among the main fruit crops cultivated in Brazil, supported by cultivar diversity, technological advances, and adaptation to diverse edaphoclimatic conditions. Rootstock selection is critical in viticulture, influencing phenology, yield, and fruit quality. This study evaluated yield- and fruit-related production parameters, cluster characteristics, and biochemical composition of ‘BRS Núbia’ table grape grafted onto different rootstocks. The experiment was conducted at the Experimental Farm of the Faculty of Agricultural Sciences (UNESP), São Manuel, São Paulo, Brazil, using a randomized block design in a split-plot scheme (three rootstocks × three seasons) with seven replicates. Rootstocks included ‘IAC 572 Jales’, ‘IAC 766 Campinas’, and ‘Paulsen 1103’, while subplots corresponded to the first three production seasons after grafting. Evaluated variables comprised bud fruitfulness, yield, productivity, physical attributes of clusters, berries, and rachises, and in 2022, berry biochemical traits, including total phenolics, flavonoids, anthocyanins, and antioxidant activity. Rootstocks did not significantly affect bud fruitfulness or yield-related parameters. In contrast, production season markedly influenced vine performance, with the third (2023) season showing higher cluster and berry mass and size. Regarding fruit composition, vines grafted onto ‘Paulsen 1103’ and ‘IAC 766 Campinas’ showed greater accumulation of total phenolics and anthocyanins than those grafted onto ‘IAC 572 Jales’, overall.