Effect of hydrogen cyanamide on bud break, vineyard productivity, and chemical composition of the must of Cabernet Sauvignon grapes

Abstract

Spraying hydrogen cyanamide on canes of Vitis vinifera L. cv. Cabernet Sauvignon in the dormant season, at the concentrations of 0, 1, 3, and 5%, caused a significant effect on the percentage of bud burst, number of clusters per vine, bud fertility, yield per bud, and yield of the vineyard. Polynomial regression analysis shows a quadratic effect, where the points of maximum were obtained with concentrations between 1.8% and 1.9%. Nevertheless, it did not cause a significant effect neither on cluster weight, berry weight, and yield per bud burst, nor on °Brix, total acidity, °Brix/total acidity, pH, density, P, K, Ca, and Mg of grape must. Bud burst was 4 days earlier with application of hydrogen cyanamide at 1%; but it was delayed in 18 days at a concentration of 5%. It also caused a uniform development of the sprouts and reduced or suppressed the apical dominance.