ISHS Acta Horticulturae 646: International Symposium on Irrigation and Water Relations in Grapevine and Fruit Trees
IRRIGATION AND WINE QUALITY OF VITIS VINIFERA CV. BOBAL IN REQUENA. SPAIN. |
| Authors: | J.L. Salón, J.V. Méndez, C. Chirivella, J.R. Castel |
| Keywords: | Berry size, stem water potential, stress integral, red and rose wines. |
| Abstract:
An experiment on drip irrigation was performed in a black grape c.v. Bobal/161-49 vineyard planted in 1983 in Requena (Valencia, Spain). The soil is a deep clay loam, Typic Calciorthid. Plant spacing was 2.45 x 2.45 m and plants were pruned to an open vase with about 12 buds per plant. Treatments consisted in an unirrigated Control (T1), and four irrigation treatments, where water was applied at different levels from flowering until near harvest. The treatments studied were: T2 (50-50-0), T3 (100-100-0), T4 (100-100-50) and T5 (100-100-100), where numbers are the percentage of the estimated ETcrop applied, respectively in each of the periods: I) flowering to fruit set, ii) fruit set to veraison, and iii) veraison to maturity. The experimental design was a completely randomised block with four replicates and 64 vines per plot. The effects of this differential irrigation on vine water status, yield, berry growth and composition, and wine quality parameters were investigated during 1999 and 2000. Irrigation increased yield in both seasons due mainly to an increase in berry weight. The concentration of juice soluble solids (Brix) and titratable acidity (TA) was unaffected by the irrigation treatment and a similar pattern was observed for the alcoholic content and TA of the elaborated wines. However, the concentration of anthocyanins, total phenolics and color intensity of both red and rose wines decreased with increasing water application in an inverse pattern to that of berry size (dilution effect). Yield, berry weight, anthocyanins, total phenolics and color intensity of red wines were closely correlated with the water stress integral (which expresses the intensity and duration of stress) calculated from early morning stem water potential determinations. Sensory evaluation by experienced tasters ranked the red wines in decreasing order of water application with preference for the unirrigated one. The main defects of the irrigated wines were attributed to visual characteristics and poorer aroma quality. | |
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