Prohexadione-calcium as a regulator of vine growth. Effect on the physical-chemical characteristics of wine grapes.

Resumo

The production of premium quality grapes requires the control of several and multiple parameters in the vineyard. Therefore, management of production yield is becoming increasingly more important for a quality vitiviniculture. At present, it seems undeniable that high crop yields give lower quality grapes than those obtained from low crop yields. Nowadays, manual cluster thinning is a very widely-used technique to reduce production in vigorous vines or in vines that have been subject to favourable weather conditions. An alternative method for controlling production is the use of plant growth regulators, which has provided successful results in other fruits.Prohexadione-calcium (Pro-Ca) is a gibberellin biosynthesis inhibitor that produces a decrease in berry size. This leads to an increase in surface-to-volume ratio, theoretically increasing the proportion of phenolic and aroma compounds, very important for grape quality. This product is easily applied by spraying and constitutes no apparent risk to consumers or the environment, because it is reported to be absorbed completely within eight hours and degraded by plants with a half-life of a few weeks and in soil with a half-life of less than one week, without producing toxic metabolites.The aim of this study was to examine the effect of Pro-Ca application on the physicochemical characteristics of Tempranillo and Grenache grape varieties. Research was carried out in two consecutive harvests 2007 and 2008. The effect of Pro-Ca on grapes was compared with grapes cultivated using manual cluster thinning and control vines. Application of Pro-Ca in both varieties shows a decrease in berry size and weight. The grapes obtained from treated vines, both manual cluster thinning and Pro-Ca, presented a higher concentration of phenolic compounds and an enhancement of colour than those from the control. Evolution of alcoholic fermentation of must from grapes treated with Pro-Ca was correct and similar to manual cluster thinning and untreated grapes. © 2012 Nova Science Publishers, Inc. All rights reserved.