Fenologia e qualidade das Vitis vinifera L. ‘Merlot’, ‘Cabernet Sauvignon’ e ‘Tannat’ submetidas a diferentes épocas de poda.

Abstract

The Campanha Gaucha region has been highlighted due to production of Vitis vinifera L. grape to make fine wines. This region extends along the border of Brazil and Uruguay whose main cities are Candiota, Bagé, Dom Pedrito and Santana do Livramento. Between the activities of utmost importance in management of viticulture activity, the dry pruning can be emphasized. In general, the dry pruning is performed in rest period, i. e. between the months of July and September, and requires a high labor demand. Thus, it is necessary to collect all the obtainable information on the phenological cycle of this culture to make easier the management and scaling of the available labor. The work aims to evaluate the phenological behavior and the quality of postharvest of the cultivars Merlot, Cabernet Sauvignon and Tannat, in different periods of dry pruning. The experiments were carried out in a commercial vineyard located in the city of Candiota, Rio Grande do Sul, during the harvest 2015/2016. The experimental design was a completely randomized design consisting of four treatments and three replications, where the treatments were the different dry pruning times performed in May, June, July and August, composing treatments 1, 2, 3 and 4 respectively. The phenological evaluations observed during the crop cycle were: sprouting, flowering, fruiting and beginning of maturation. After the harvest the variables evaluated in the wort were the total soluble solids, sugars, titratable acidity, pH and density. The total number of bunches per treatment, number of bunches per plant, total mass of bunches per treatment and average mass of bunches per plant were evaluated for the production calculation. Data were submitted to analysis of variance (Anova) and comparison of means by the Tukey test at 5%. The 'Tannat' vine pruned in August had a later phenological behavior in relation to the other treatments. After sprouting, the plants pruned in June developed faster than the others. The different seasons of dry pruning did not interfere with production. When dry pruning is performed in August, the 'Tannat' harvest may be later. For 'Cabernet Sauvignon' the early pruning of the month of May remains longer in dormancy, sprouting at the same time as the plants pruned in July. The pruning done in June anticipates the sprouting and can cause damages caused by the spring frosts. The pruning done in August obtained higher yield per plant when compared to the traditional season in July. Dry pruning at different times did not influence the analytical characteristics of the must. In the 'Merlot' grapevine, the dry pruning carried out in the month of June anticipated the sprouting and when it was carried out in the month of August it obtained a total number and a total mass of bunches higher than the one realized in the month of June.The different seasons of dry pruning did not differentiate the results of the physical-chemical variables of 'Merlot'.