This research was an attempt to evaluate the trunk girdling effect to hasten the maturation of table grapes produced out of season in the northwest of Parana state, Brazil. The trial was carried out in three vineyards of 'Rubi' (Vitis vinifera L.) and the girdling consisted of removing a narrow ring of bark entirely round of the trunk using a double-bladed 3.1 mm knife, 1.5 m far from the ground. The technique was applied during the early ripening period, which took place in early April, 2001. A randomized block design with two treatments (girdling and control) and four replications was used as an statistical model for each location. Each plot was composed by one plant. Total soluble solids (TSS) and titratable acidity (TTA) were evaluated weekly through berries samples collection, from the establishment of the experiment up to its harvesting, totalizing six samplings for each location. Both TSS and TTA presented linear correlation as function of time for both treatments and through linear regression, it was estimated the period the clusters reached the maturation, considering 14 ºBrix as standard. The period of maturation hastening in girdled plants in relation to the control ones ranged from 3 to 12 days. There was no difference in relation to the TTA decrease pattern in berries in both girdled and control treatments for all locations.
Vitis vinifera L.; grapevine; soluble solids; titratable acidity
