Physical and chemical characteristics of grape clusters from Vitis rotundifolia cultivars

The goal of this work was to evaluate physical and chemical cluster characteristics of eight Vitis rotundifolia cultivars: Topsail, Magnolia, Noble, Roanoke, Magoon, Regale, Bontiful and Dixie. The evaluated clusters were collected from a preexistent Vitis rotundifolia orchard located at the Canguiri Experimental Station of the Federal University of Parana, in Pinhais-PR. The following variables were evaluated for the 2004 and 2005 crops: total cluster mass, berry mass per cluster, rachis mass, number of berries per cluster and berry diameter. A completely random design with 50 replications was used and each cluster has been considered as a parcel. The chemical characteristics of the juice were evaluated: pH, acidity and total soluble solids. For these analyses, a completely random design with 10 replications was used with 5 clusters per plot. The cultivar Noble stood up from the rest in terms of total soluble solids content for both crops (2004 and 2005) with 12.7 degrees and 13.7 degrees Brix respectively. The cultivar Dixie presented the highest pH (3.04) in 2004 and the cultivar Magnolia in 2005, which present the lower acid content in both years. The cultivars Magnolia and Roanoke stood up in 2004 and 2005 respectively in total cluster mass, mass of berries and rachis mass. In terms of number of berries per cluster, the cultivars Roanoke and Magnolia presented the highest numbers in 2004 while in 2005 the highest numbers were presented by the Roanoke, Regale and Noble cultivars. In 2004, the average berry mass of the cultivars Magnolia and Topsail was superior to the others being the last cited cultivar also superior in this variable in 2005. The cultivar Noble presented the smallest diameter of berries. It was possible to conclude that Vitis rotundifolia cultivars, due to their low total soluble solids content, high acidity and low pH are not recommended for fresh consumption but present potential for juice, jam and jelly production. Furthermore, the cultivars presented small clusters with few berries, being considered inferior than clusters from other american grapevines.