Influence of vigour on vine performance and berry composition of cv. Sangiovese (Vitis vinifera L.)

Aims : To test the effects of varying degrees of vigour on vine growth, cropping, grape composition and wine quality. Methods and results : The study was conducted in 2008-2009 in a cv. Sangiovese (V. vinifera L.) vineyard (Tuscany). Two uniform zones marked by low (LV) and high (HV) vigour vines were pinpointed using an NDVI (normalized difference vegetation index) map. Soil analysis showed similar texture in both zones, but total soil nutrients were lower in LV than in HV. While only LV vines showed soil water content close to wilting point in 2008, they demonstrated lower leaf area and yield and higher berry sugar and anthocyanin concentrations compared to HV vines. Chemical and wine tasting analysis of the wines made in 2009 showed that the LV wines had better sensory attributes than the HV wines, despite their excessive ethanol content. Conclusions : The differences in vigour, yield and must and wine quality of LV compared to HV vines were linked to variations in soil fertility and water retention capacity. Precision vineyard management practices like supplementary fertilization and irrigation should be used to increase vigour and yield and to decrease sugar content in LV grapes. Cover crop may be used in HV vines to decrease their vigour and yield. Significance and impact of the study : The study confirms that the evaluation of within-field variability is crucial for site-specific vineyard management.