Influência de porta-enxertos no desenvolvimento, produtividade, qualidade da uva e do suco da BRS Magna

Abstract

Brazilian grape juices are predominantly derived from Vitis labrusca grapes, representing more than 80% of total production in the country. ‘BRS Magna’ was launched with the aim of improving sensory attributes such as the color, sweetness and flavor of the grape juice produced. However, it is necessary to test this cultivar on different rootstocks, as these promote different effects on the scion cultivar, influencing vigor, yield components and fruit quality, as well as the quality of products. However, this influence is dependent on the specific affinity of the scion/rootstock/environment interaction. Therefore, the objective of the work was to evaluate which rootstock is most suitable for the cultivar 'BRS Magna'. The work was carried out in the vineyard established in the experimental area of the Universidade Tecnológica Federal do Paraná (UTFPR), located in the municipality of Pato Branco, Paraná. 'BRS Magna' was grafted onto 10 rootstocks: 'Kober 5BB', 'SO4', 'IAC 766 Campinas', 'Harmony', 'Paulsen 1103', '420A', ‘Freedom’, 'IAC 572 Jales', 'IAC 313 Tropical' and '101-14 MGT'. In three production cycles, vigor parameters, yield components, maturation evolution, physical-chemical characteristics of the berry, gas exchange, incidence of mildew, mineral nutrition, underdevelopment and death of plants, in addition to the chemical and sensorial profile of the juices. The highest plant vigor was obtained with the rootstock ‘IAC 572 Jales’, while ‘101-14 MGT’ and ‘420 A’ induced low vigor in the scion cultivar. The highest productivity was obtained with ‘IAC 572 Jales’ and ‘SO4’, while ‘420 A’ and ‘101-14 MGT’ were the lowest. The ‘420 A’ rootstock induced inefficiency in the gas exchange of the scion cultivar, especially in plants affected by Yuong Vine Decline (YVD). No rootstock induced downy mildew resistance to ‘BRS Magna’, only some combinations were more tolerant than others. The macronutrient contents in the leaf tissue and in the bunch were influenced by the rootstock. Plants grafted onto lower vigor rootstocks showed higher levels of soluble solids, lower acidity and, consequently, a higher ripeness index (ratio) in the berry pulp. The experimental juice of ‘BRS Magna’ grafted onto the ‘Kober 5BB’ rootstock achieved greater acceptance and purchase intention. Considering all evaluations carried out and the experimental conditions, the recommended rootstock for growing ‘BRS Magna’ scion is ‘IAC 572 Jales’. On the other hand, ‘101-14 MGT’ and ‘420 A’ are not recommended as rootstocks for this cultivar. Therefore, choosing the appropriate rootstock is crucial to optimize the production and quality of grape juice, contributing to the advancement of Brazilian viticulture.