Physical chemical characteristics of ‘Marselan’ grape under clusters thinning in Serra do Sudeste, RS, Brazil

Abstract

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.