Cultivares e porta-enxertos de videiras para produção de vinhos finos de inverno em clima subtropical

Abstract

Excessive rains in summer affect the ripening of the grapes, negatively affecting the quality of the grapes and wines. In this sense, it is interesting to change the harvest time to favorable times for the maturation of the grapes, such as the double pruning management, which aims to produce grapes in the first half of the year with harvest in the driest months. Cultivar ‘Syrah’, the first that showed adaptability to the management of double pruning, is currently the most outstanding in this untimely production. In this sense, evaluations were carried out in the harvests of 2020 and 2021 with the objective of evaluating the implantation of new cultivars in this double pruning management. Conducted under subtropical climate conditions in the region of Lavras, the treatments consisted of seven Vitis vinifera cultivars: 'Carmenere', 'Marsanne', 'Marselan', 'Touriga Nacional', 'Muscat Petit Grain', 'Petit verdot' and ' Syrah', and two rootstocks of different vigor: IAC766 and 1103 Paulsen. The vines were cultivated in an espalier and pruned in a double spore cord, without the use of irrigation. Yield evaluations were carried out in two cycles, 2020 and 2021, while ecophysiological analyzes were only evaluated in 2020. The variables evaluated were: winter pruning mass, bud fertility, chlorophyll index, leaf surface, soluble solids content , pH, titratable acidity, mass, diameter and number of berries, bunch masses, production per plant and base leaf water potential. The data were subjected to analysis of variance and means compared by the Scott-knott test (p<0.05) There was a greater tendency to water deficit of vines grafted on the rootstock IAC766 and especially on the cultivars Marsane and Marselan. The evaluation of the relative chlorophyll index can be an alternative when evaluating the vigor of plants under management conditions that require a greater number of growth cycles. It was observed a trend of low vigor cultivars to lower estimated chlorophyll contents, such as 'Petit verdot', on the other hand, excess vigor was observed to the detriment of the productive parameters of the cultivar Touriga Nacional. The tendency to be more productive and more vigorous did not compromise the chemical values of the must of the rootstock cultivars IAC766. A greater contribution of climatic conditions was observed during the ripening of the grapes, especially in years with drier winters. It is concluded that the rootstock IAC766 are more recommended due to the greater vigor conferred, cultivars such as Marselan, Marsane, Syrah and Touriga Nacional have potential in the production of winter wines and it is necessary to manage the crowns Touriga Nacional, Petit Verdot and Carmenere regarding the excess and insufficient vigor and fertility of the buds.