Grape maturation and quality for juice production in tropical conditions in the initial production cycles

Abstract

The objective of this work was to characterize the maturation and the grape quality of the cultivars Isabel Precoce and BRS Cora, grafted onto 'IAC 572' rootstock, in order to determine harvest time. The experiment was carried out in the Submédio São Francisco river basin, Brazil, during the production cycles from November 2009 to March 2010 and from June to  September 2010, in a randomized complete block design, with four replicates constituted by five bunches. The bunches were periodically collected from the beginning of the maturation, which for 'Isabel Precoce' grapes corresponded to 54, 61, 68, 71, 74, and 77 days after fruit set (DAF), in the first cycle, and to 49, 56, 63, 67, 71, 74, and 77 DAF, in the second one. For 'BRS Cora', the bunches were collected at 61, 68, 71, 74, 77, and 82 DAF, in the first cycle, and at 53, 60, 65, 70, 74, and 78 DAF, in the second cycle. The 'BRS Cora' grapes are more acid than the 'Isabel Precoce' ones; however, they show the highest contents of soluble solids and soluble sugar. The harvest time for 'Isabel Precoce' grapes occurred at 77 DAF in both productive periods; for 'BRS Cora' grapes, it occurred at 82 DAF, in the first semester, and it was anticipated by four days in the second one.