The cultivar Malbec has been present's good performance and quality in the South Half of Rio Grande do Sul (RS). In this context, we aimed to evaluate the quality of "Malbec" grapes in relation to the phytotechnical, physicochemical parameters and bioactive compounds under different intensities of cluster thinning in Encruzilhada do Sul-RS. The experiment was carried out in a commercial vineyard in the 2015/16 with the cultivar Malbec (Vitis vinifera L.) under rootstock "1103 Paulsen", with spacing of 2.2 m between rows and 1.1 m between plants. The experimental design was of randomized complete blocks with five replications. The treatment factor tested was the cluster thinning, with four levels (0%, 10%, 30% and 50%), performed in véraison. The evaluated phytotechnical variables were cluster length, cluster fresh weight, berries fresh weight, number of berries, rachis fresh weight. Also what were determined are the number of clusters, production and Ravaz index. The physicochemical variables verified were pH, soluble solids (SS), titratable acidity (TA) and SS/TA ratio. The bioactive compounds were total polyphenols index and total anthocyanins. The appropriate balance between source and sink, by the Ravaz index, occurs to zero and 10% of cluster thinning. The "Malbec" grapes present an increase of the maturation index (SS/TA) at 50% of cluster thinning, due to the low titratable acidity at this level. The total polyphenols index has a larger increment when the plants are submitted to the cluster thinning of 10%, providing a larger quality to the fruits. At all the levels of cluster thinning tested, when compared to the control, there was a greater contribution of total anthocyanins in the berries.

the aim of this study was to evaluate the chemical characteristics and sensory acceptance of juices and cuts of ‘Bordô’ and ‘Niágara Rosada’ grapes. The experimental design was in a one-factor scheme, with five levels. Treatments were: T1 – ‘Bordô’ (100%); T2 – ‘Bordô’ (70%) + ‘Niágara Rosada’ (30%); T3 – ‘Bordô’ (50%) + ‘Niágara Rosada’ (50%); T4 – ‘Bordô’ (30%) + ‘Niágara Rosada’ (70%); T5 – ‘Niágara Rosada’ (100%). Chemical analyses were: content of soluble solids, pH and titratable acidity, and sensory analyses were: color, aroma, flavor, body and global acceptance. For the soluble solids content, the highest averages were verified in T1, T2 and T3 treatments. As for pH, the highest value was recorded in T3, T4 and T5 treatments, while the highest titratable acidity was recorded in T4 and T5 treatments. In the sensory analysis, in juice with the highest percentage of ‘Bordô’ grape (T1 and T2) or with the same proportion of ‘Bordô’ and ‘Niágara Rosada’ (T3), the highest mean acceptance values were found. Thus, it could be concluded that the use of 100% ‘Bordô’ grape and ‘Bordô’ juice cut with up to 50% ‘Niágara Rosada’ are presented as alternatives for juice production.

AGRONOMIA (AGRONOMY)RESUMO: Este experimento teve como objetivo avaliar o efeito de diferentes intensidades de raleio de cachos nas características físico-químicas da 'Marselan' na Serra do Sudeste-RS. O estudo foi realizado na safra 2015/16 em vinhedo comercial no município de Encruzilhada do Sul. A cultivar utilizada foi a Marselan (Vitis vinifera L.) sobre porta enxerto Paulsen 1103 e espaçamento de 2,2m entre fileiras e 1m entre plantas. O delineamento experimental foi de blocos completos casualizados em esquema unifatorial, com cinco repetições. O fator de tratamento testado foi o raleio, com quatro níveis (0, 10, 30 e 50%), realizado no véraison. As variáveis avaliadas foram comprimento e massa fresca de cachos, massa fresca e número de bagas e massa fresca de ráquis. Também foi determinado o número de cachos, produção por planta e o índice de Ravaz. Foram verificadas o pH, sólidos solúveis (SS), acidez titulável (AT), a razão SS/AT, índice de polifenóis e antocianinas totais. A 'Marselan' quando submetida a 0 e 10% de raleio de cachos obteve adequado índice de Ravaz, indicando que a relação carga vegetativa está proporcional a produção por planta nesses níveis. Para todas as outras variáveis, a intensidade de raleio de cacho não proporciona incremento na qualidade da uva 'Marselan' na Serra do Sudeste-RS. Palavras-chave: índice de Ravaz; remoção de cachos; véraison; Vitis vinifera Physical chemical characteristics of 'Marselan' grape under clusters thinning in Serra do Sudeste, RS, BrazilABSTRACT: This observation, this experiment aimed to evaluate the effect of different intensities of cluster thinning in the physicochemical characteristics of 'Marselan' grape in the Serra do Sudeste, RS, Brazil. The cultivar used was the Marselan (Vitis vinifera L.) on Paulsen 1103 grafted and 2.2m spacing between rows and 1m between plants. The study was carried out in the 2015/16 harvest in a commercial vineyard in the municipality of Encruzilhada do Sul. The experimental design was a randomized complete block with five replications. The treatment factor tested was the cluster thinning, with four levels (0, 10, 30 and 50%), performed in véraison. The evaluated variables were length clusters, fresh cluster mass, fresh berries mass, number of berries, fresh rachis mass. The number of clusters, production per plant and Ravaz index were also determined pH, soluble solids (SS), titratable acidity (TA), ratio SS/TA, total polyphenol content and total anthocyanins. The 'Marselan' when submitted to 0 and 10% of cluster thinning obtained an adequate Ravaz index, indicating that the relation vegetative load is proportional to the production per plant at these levels. For all other variables, the intensity of cluster thinning does not increase the 'Marselan' grape quality in the Serra do Sudeste-RS.Características físico-químicas de uva 'Marselan' sob raleio de cachos na Serra do Sudeste-RS Rev. Bras.

The grapevine (Vitis spp.) is the one main fruit grown in the world. One of the primary requirements of production destined to be consumpted in natura is the acceptance of product in the consumer market. Thus, the aim of this work was to evaluate the physico-chemical characteristics and the sensorial acceptance of grapes 'Niágara Rosada' and 'Niágara Branca'. The experimental design was in a one-factor scheme, with two levels. The evaluated variables were bunch length, berry diameter, soluble solids content, pH and titratable acidity. For the sensorial evaluation, the attributes color, aroma, sweetness, acidity, flavor and overall acceptance were evaluated using a hedonic scale of nine points, besides the intention to buy. The 'Niágara Branca' presented higher mean for cluster length and 'Niágara Rosada' for berry diameter. For soluble solids and titratable acidity, 'Niágara Rosada' presented higher mean. In the sensory analysis, the 'Niágara Rosada' obtained the highest note for color and the 'Niágara Branca' for sweetness; however, the two cultivars had good overall acceptance, with grades between 8.3 and 8.4. It is concluded that the 'Niágara Rosada' and the 'Niágara Branca' presented good acceptance by the evaluators.