Efficiency of hydrogenated cyanamide, spreader-sticker and torsion of the canes to break bud dormancy in grapevine cv. Italia in the São Francisco Valley

Abstract

In the tropical climate of the São Francisco Valley, Northeast of Brazil, grapevine presents bud dormancy and high apical dominance. The present work aimed to evaluate the effects of hydrogenated cyanamide, spreader-sticker and torsion of the canes to overcome that dormancy as well as on yield and fruit quality of the cv. Italia. The experiment was carried out in Petrolina (PE) during two production cycles (200-2002). The treatments were as follows: T: control; T2: H2CN2 2.45%; T3: H2CN2 2.94%; T4: H2CN2 3.43%; T5: H2CN2 2.94% + Break- Thru® 0.03% and T6: H2CN2 2.45% + torsion of the canes, in a randomized complete block design with four repetitions. The results showed that the hydrogenated cyanamide, independently of the concentration, increased the bud germination and yield, with increments of 22% and 522% in the yield per plant, respectively in the st and 2nd production cycles. There was no significant effect on berry size, fruit sugar content and acidity as well as on earliness of harvest. There was no answer to the spreader-sticker. Submitting the canes to a torsion showed to be a practice capable of increasing the effects of the hydrogenated cyanamide.Additional keywords: bud germination; yield; quality.