ISHS Acta Horticulturae 206: Symposium on Grapevine Canopy and Vigor Management, XXII IHC
USEFULLNESS OF GROWTH REGULATORS FOR CONTROLLING VINE GROWTH AND IMPROVING GRAPE QUALITY IN INTENSIVE VINEYARDS |
| Author: | S. Lavee |
| Abstract:
Intensive vineyards tend to develop an excessive vegetative growth which often leads to massive shading. Such conditions might cause a reduction in productivity of the lower part of canes and whole vines. The severity of this problem increases particularly in the early years of vineyard development. Uniform bud break is critical for balanced growth and even maturation. The response of various vine forms and treatments to controlled bud break and vegetative growth were studied. Vertical vine forms were more productive than horizontal ones. However, shading in such vines was more severe due to expressed polarity. Dormancy breaking agents and particularly H2CN2 was found to control both time and uniformity of bud opening, and helped to overcome apical dominance. This effect was often carried through till maturation. Controlled pruning, sectorial chemically enhanced bud opening and physiological control of vegetative growth enabled overcoming the shading effect. In most cases 12 leaves above the bunch enabled normal fruit development. Chemical control of excess growth by means of ethephon applications caused a better light penetration to the vineyard and more uniform maturation. The effect of such treatments on time of maturation was only minor and insignificant. Chemicals reducing vigor by shortening the internodes had no effect on the long term fruiting ability. New approaches to vine training based on utilization of the apical dominance could be efficiently combined with chemical growth control to achieve an annual high production. Direct effects of growth regulators on fruit maturation, such as ethephon for coloration, gibberellins for size and auxins on bunch properties, are of significant importance for maintaining quality at high yields. Growth enhancement of vines could be achieved by gibberellic acid. This however did not lead to increased productivity in weakly growing vines, and reduced it in medium and vigorous ones. Preliminary results on growth control were demonstrated with paclobutrazol and on berry size with chloropyridylphenylurea. The relative efficiency of the different methods to maintain high quality in a heavily producing vineyard is discussed. | |
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