EFFECT OF SHOOT AND BUNCH DENSITY ON YIELD AND QUALITY OF 'SUGRAONE' AND 'THOMPSON SEEDLESS' TABLE GRAPES

This study aimed to evaluate the effect of shoot and bunch density through thinning practices on yield components and quality of 'Thompson Seedless' and 'Sugraone' grapevines in the Sao Francisco River valley. The experiments were carried out during two growing seasons (2010 and 2012) in commercial vineyards of Lagoa Grande, state of Pernambuco, Brazil. Treatments were a split plot represented by three shoot densities and three bunch densities in a random block design. The yield of 'Thompson Seedless' grapevine was up to 25.9% higher in plants kept with 6 bunches. m(-2), reaching 20.7 and 27.0 kg. plant(-1) , in the 2010 and 2012 crop years, respectively. Although effects on yield were not observed in 'Sugraone' cultivar, bunch and berry mass was higher in treatments with 5 bunches. m(-2) and 7 shoots. m(-2), respectively, in the last production cycles. 'Thompson Seedless' grapes with greater berry firmness were harvested in 2012 in plants submitted to densities of 7 or 8 shoots. m(-2), while the contents of soluble solids and total soluble sugars were higher in grapes harvested from plants with lower shoot and bunch densities. However no effects of treatments on the contents of soluble solids were observed in 'Sugraoen' grapes. The use of 7 shoots. m(-2) associated to 6 bunches. m(-2) is recommended for 'Thompson Seedless' grapevines because it increased yield with no harm to fruit quality, while for 'Sugraone', densities of 7 shoots. m(-2) and 5 bunches. m(-2) can be used to increase the mass of bunches and berries.