In the last years, particularly in the viticultural areas characterized by low soil fertility and water availability, when the skin berry colour of red-varieties is considered optimal for harvest, the juice sugar concentration is often too high, giving rise to wines with high alcohol levels which are not well accepted by modern consumers. On the other hand is not possible to anticipate the time of harvest because of the risk of incomplete poliphenols synthesis which is known to start at veraison. Late trimming, enabling to decrease leaf area/yield ratio during the last phase of berry maturation, may represent a cheap and simple agronomical practice for slowing down sugar accumulation. However is not clear if late trimming may also delay anthocyanins accumulation in berry skin. With the aim of testing such hypothesis a 3-year experiment (2008-2010) was conducted in a mature Sangiovese vineyard located in a hot hilly area of Emilia-Romagna Region (Tebano, Ravenna, Italy), treated with different intensity of late (post-veraison) shoot trimming. In August, when grape soluble solids reached about 15 °Brix (40-45 days before expected harvest), spur-pruned vines were submitted to trimming maintaining 14 (light trimming) or 10 (severe trimming) nodes on the main shoot and compared with control non-trimmed vines. A randomized block design was adopted. Berry weight and their soluble solids, total acidity and pH were monitored several times after treatment, while skin anthocyans, fruit yield and cluster weight were determined at harvest. Berry quality data (berry weight, soluble solids, pH, total acidity and yeast assimilable nitrogen, skin anthocyans concentrations) collected during 2008 and 2009 indicate a slowing-down of maturation in the berries collected on trimmed vines. Nevertheless skin anthocyans levels at harvest did not show statistical differences with control vines. Trimming decreased bunch weight and yield. In 2010 year, characterized by different metereological conditions (lower summer temperatures), trimming did not change sugar accumulation while inducing a small decrease of berry skin anthocyanins concentration (peonidin). These results suggest that late trimming may represent an effective tool for slowing down sugar accumulation without changing phenolic maturity. Furthermore, data indicate that late trimming practices should be performed and finely adjusted to metereological conditions and berry maturation trend.
ROMBOLA’ A.D., COVARRUBIAS J.I., BOLIANI A.C., MARODIN G.A., INGROSSO E., INTRIERI C. (2011). Post-veraison trimming practices for slowing down berry sugar accumulation and tuning technological and phenolic maturity. V. Novello; M. Bovio; S. Cavalletto.
Post-veraison trimming practices for slowing down berry sugar accumulation and tuning technological and phenolic maturity
ROMBOLA', ADAMO DOMENICO;INTRIERI, CESARE
2011
Abstract
In the last years, particularly in the viticultural areas characterized by low soil fertility and water availability, when the skin berry colour of red-varieties is considered optimal for harvest, the juice sugar concentration is often too high, giving rise to wines with high alcohol levels which are not well accepted by modern consumers. On the other hand is not possible to anticipate the time of harvest because of the risk of incomplete poliphenols synthesis which is known to start at veraison. Late trimming, enabling to decrease leaf area/yield ratio during the last phase of berry maturation, may represent a cheap and simple agronomical practice for slowing down sugar accumulation. However is not clear if late trimming may also delay anthocyanins accumulation in berry skin. With the aim of testing such hypothesis a 3-year experiment (2008-2010) was conducted in a mature Sangiovese vineyard located in a hot hilly area of Emilia-Romagna Region (Tebano, Ravenna, Italy), treated with different intensity of late (post-veraison) shoot trimming. In August, when grape soluble solids reached about 15 °Brix (40-45 days before expected harvest), spur-pruned vines were submitted to trimming maintaining 14 (light trimming) or 10 (severe trimming) nodes on the main shoot and compared with control non-trimmed vines. A randomized block design was adopted. Berry weight and their soluble solids, total acidity and pH were monitored several times after treatment, while skin anthocyans, fruit yield and cluster weight were determined at harvest. Berry quality data (berry weight, soluble solids, pH, total acidity and yeast assimilable nitrogen, skin anthocyans concentrations) collected during 2008 and 2009 indicate a slowing-down of maturation in the berries collected on trimmed vines. Nevertheless skin anthocyans levels at harvest did not show statistical differences with control vines. Trimming decreased bunch weight and yield. In 2010 year, characterized by different metereological conditions (lower summer temperatures), trimming did not change sugar accumulation while inducing a small decrease of berry skin anthocyanins concentration (peonidin). These results suggest that late trimming may represent an effective tool for slowing down sugar accumulation without changing phenolic maturity. Furthermore, data indicate that late trimming practices should be performed and finely adjusted to metereological conditions and berry maturation trend.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
