Impact of leaf removal after berry set on fruit composition and bunch rot in 'Sauvignon blanc'

D. Mosetti ^[1] ; J.C. Herrera ^[1] ; P. Sabbatini ^[2] ; A. Green ^[2] ; G. Alberti ^[1] ; E. Peterlunger ^[1] ; K. Lisjak ^[3] ; S.D. Castellarin ^[1]
1. [1] Università di Udine
  
  Università di Udine
  
  Udine, Italia
2. [2] Michigan State University
  
  Michigan State University
  
  City of East Lansing, Estados Unidos
3. [3] Agricultural institute of Slovenia
  
  Agricultural institute of Slovenia
  
  Eslovenia
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Localización: Vitis: Journal of Grapevine Research, ISSN 0042-7500, Vol. 55, Nº 2, 2016, págs. 57-64
Idioma: inglés
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Resumen
- Leaf removal is a viticultural practice applied to improve cluster microclimate and grape quality. This practice can reduce the incidence of bunch rots but could also promote the degradation of berry methoxypyrazines, key components for the quality of Sauvignon blanc wines. The influence of cluster-zone leaf removal, applied after berry set, was evaluated on Sauvignon blanc grapevines grown in the Isonzo DOC region (Italy). In 2010 and 2011, yield components and fruit chemical composition were recorded from vines in which the five basal leaves of each single shoot were manually removed at the groat-sized phenological stage, and compared to untreated vines. Our results indicated that leaf removal did not influence yield or fruit composition at harvest, but significantly decreased the incidence and severity of Botrytis bunch rot, while avoiding sunburn damage to the fruit. Our results also demonstrated that increased cluster exposure to sunlight, lowered 2-methoxy-3-isobutylpyrazine (IBMP) and 3- isopropyl-2-methoxypyrazine (IPMP) levels at early stages of berry development but, at harvest, the berry IBMP and IPMP concentration was found to be undetectable in both defoliated and non-defoliated vines. We conclude that leaf removal performed after berry set is a pivotal viticultural management practice to cope with harvest bunch rot complex without negatively affecting fruit composition at harvest.