EFFECTS OF HYDROGEN CYANAMID ON BUD BREAKING OF THE GRAPEVINE 'ITALIA' IN THE SÃO FRANCISCO RIVER VALLEY

Abstract

Under tropical climate conditions, as in the Sao Francisco River Valley, Northeast Brazil, grapevine presents bud dormancy and high apical dominance. The present work aimed at evaluating the effects of hydrogen cyanamid, spreader-sticker and torsion of the canes on grapevine bud break, yield and fruit quality of the ‘Italia’ table grape cultivar, in the Sao Francisco River Valley. The experiment was carried out at Petrolina-PE, in the semi-arid region of Northeast Brazil, during two harvest seasons (2001–2002). The treatments were as follows: T1: control; T2: H2CN2 2.45%; T3: H2CN2 2.94%; T4: H2CN2 3.43%; T5: H2CN2 2.94% + BreakThru ® 0.03% and T6: H2CN2 2.45% + torsion of the canes, in a randomized complete block design with four repetitions. The results showed that hydrogen cyanamid, independent of the concentration, increased bud burst and bud fruitfulness, with increments of 68% and 84% in the yield per plant, respectively in the 1 st and 2 nd d harvest seasons. There was no significant effect on berry size, sugar and acidity content of the fruits and harvest anticipation. There was no answer to spreader-sticker. On the other hand, the practice of cane torsion presented a tendency to increase the effects of the hydrogen cyanamid.