Altura do dossel vegetativo 'Cabernet Sauvignon' no Município de Dom Pedrito – Rio Grande do Sul (RS): impacto na produtividade e na qualidade do vinho

Abstract

The objective of the present work was to evaluate the influence of the height of the vegetative canopy on the productivity, physico-chemical compositions of must and wine of the Cabernet Sauvignon cultivar, as well as on the phenolic composition (anthocyanins, stilbenes and flavonoids) and their impact on the methoxypyrazine content of the wines. Therefore, four heights of vegetative canopy were tested: 60 cm (T1), 80 cm (T2), 100 cm (T3) and 120 cm (T4). The experiment was conducted in a commercial vineyard located in the region of Campanha Gaúcha Dom Pedrito, RS, (31 ° 01 ′ S, 54 ° 36 ′ W, altitude 159 m), in the cycles 2015/16, 2016/17, 2017/18 and 2018/19. The main agronomic variables were analyzed (estimated productivity per plant and per hectare, average weight and number of clusters). The wines were made using traditional methodology, all in the same way, and the physico-chemical analyzes of must and wine were carried out using Fourier transform infrared spectroscopy (FTIR). Phenolic analysis was performed by high performance liquid chromatography and UV / Vis spectrophotometry. The quantification of methoxypyrazines by means of solid phase microextraction using “headspace” (HS-SPME) followed by gas chromatography coupled with mass spectrometry (GC-MS). Agronomic variables were not influenced by treatments. Regarding the physical and chemical characteristics of the must and wine, despite having statistical differences for some parameters in certain vintages, it was not possible to highlight even one treatment. There was little influence on the individual quantification of anthocyanins, but a strong influence of each cycle on their profile. The wines had low levels of methoxypyrazines, and did not differ from each other.