ISHS Acta Horticulturae 689: VII International Symposium on Grapevine Physiology and Biotechnology
REFLECTIVE MULCH TO ENHANCE BERRY QUALITY IN ONTARIO WINE GRAPES |
| Authors: | J.M. Coventry, K.H. Fisher, J.N. Strommer, A.G. Reynolds |
| Keywords: | anthocyanin, flavonol, phenolics, insects, light |
| Abstract:
The Niagara wine region of Ontario is at the northern fringe of adaptability for Vitis vinifera. In some growing seasons many V. vinifera cultivars do not reach full maturity before the impending winter forces harvest. It has been demonstrated in many studies that sunlight is critical to quality grape production through its effect on photosynthesis and on the expression of genes involved in production of secondary metabolites important to grape quality. Reflective mulch has the potential to improve berry quality through its effect on the microclimate within the canopy and in particular light penetration into the fruiting zone. A multi-varietal trial was established in a commercial vineyard in 2003 to determine the effect of reflective mulch on berry, must and wine quality of Ontario grown V. vinifera grapes. It was hypothesised that increased light resulting from the reflective mulch would improve berry quality, which would in turn produce deeply colored wines with pleasantly, complex sensory characteristics. Results reported in this paper are limited to the cultivar ‘Cabernet Franc’ portion of this study, which includes an assessment of microclimate within the canopy, berry quality over development from cluster closure to harvest and an experiment to determine the effect of reflective mulch on insect populations within the canopy. The reflective mulch product used in this study deteriorated significantly over the season becoming oxidized, dirty and in some cases losing it reflective coating. While this deterioration undoubtedly impacted the results of this study, mulch enhanced the quantity and quality of light into the fruiting zone, advanced veraison and in general increased °Brix, total phenolics, flavonols and anthocyanins of ‘Cabernet Franc’ berries at harvest. Mulch also reduced the number of insects trapped in the canopy especially aphids and leafhoppers. These results indicate there is potential for reflective mulch to improve berry quality in Niagara grown grapes, particularly in a late, cool or short growing season. | |
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