Early defoliation (hand vs mechanical) for improved crop control and grape composition in Sangiovese (Vitis vinifera L.)
Article first published online: 24 MAR 2008
© 2008 Australian Society of Viticulture and Oenology Inc.
Australian Journal of Grape and Wine Research
Volume 14, Issue 1, pages 25–32, April 2008
How to Cite
INTRIERI, C., FILIPPETTI, I., ALLEGRO, G., CENTINARI, M. and PONI, S. (2008), Early defoliation (hand vs mechanical) for improved crop control and grape composition in Sangiovese (Vitis vinifera L.). Australian Journal of Grape and Wine Research, 14: 25–32. doi: 10.1111/j.1755-0238.2008.00004.x
- Issue published online: 24 MAR 2008
- Article first published online: 24 MAR 2008
- Manuscript received: 6 September 2007; Revised manuscript received: 12 December 2007; Accepted: 17 January 2008
- berry weight;
- source–sink balance
Background and Aims: The number of pre-bloom source leaves is a primary determinant of subsequent fruitset. Accordingly, we tested whether pre- and post-bloom hand (HD) and mechanical (MD) defoliation are effective in limiting the yield of a high-cropping cultivar such as Sangiovese in a 3-year field study.
Methods and Results: The first six basal leaves and any laterals were removed by hand, and the same area was subjected to MD, the latter removing 48.3% of the leaf area removed manually. Both treatments significantly reduced fruitset, yield per shoot, bunch weight, berries per bunch and bunch compactness. Yield/ha declined from 32.8 tons in control vines to 24.4 and 19.0 tons for MD and HD (pre- and post-bloom treatment means), respectively. Leaf-to-fruit ratios were unaffected by defoliation as source loss was fully offset by yield decline. Soluble solid concentration and total anthocyanins on a fresh-weight basis increased by 2.4°Brix and 0.2 mg/g in HD and by 2.2°Brix and 0.08 mg/g in MD as compared with that in non-defoliated control.
Conclusions: Although results from HD reinforce the physiological basis of the technique's effectiveness, MD proved likewise effective in reducing yield and improving grape quality.
Significance of the Study: Early MD has the potential to regulate yield in a timely and cost-effective fashion.