Vitis vinifera ‘Barbera’ is the second red-grape variety for vineyard surface in Italy and the most widely cultivated (34 % of the total vineyards) in Piedmont (North-West Italy) where it is the base for VQPRD wines such as ‘Barbera d’Alba’, ‘Barbera d’Asti’ and ‘Barbera del Monferrato’. Fifteen clones have been selected and at present registered in Italy (AA.VV., 2005). In the present work the polyphenolic contents of clones of different origin were compared in the same environment. A PCA model was studied to reveal those variables which were highly correlated and which were able to differentiate clones. The trial was carried out in 2002 and in 2004 on vines planted in 1997, vertically trained and Guyot pruned. The vineyard, East-exposed and located in Monforte d’Alba (CN) was set in 3 randomised blocks of 5 vines each. At harvest berry skins of the studied clones (the registered clones AT-84, CVT 83, BA-AL-128, BA-AL-132, 17-BA, MI-B-34, PC-BA-26, MI-B-12 and the clones GJ1, GJ2, OB63 and OB66, under evaluation for possible homologation) were analysed for total anthocyanins and polyphenols by spectrophotometry and for anthocyanin profile, flavonols, hydroxycynnamoyl acid esters (HCTA) and free hydroxycinnamic acids (HCA) by HPLC (Di Stefano and Cravero, 1991). The two years of trial presented quite different meteorological conditions, 2002 being very fresh and wet with a total degree days (base 10°C) of 1653 °C and a total rainfall of 822 mm whereas 2004 was in the average, with a total degree days of 1773 °C and a total rainfall of 433 mm. ‘Barbera’ is a 3’,5’-substituted anthocyanin prevalent variety (delphinidin-3-glucoside, petunidin-3-glucoside and malvidin-3-glucoside together accounting for 70 % of the total anthocyanin content); the total acylated form percentages range from 12 to 20 %. In berry skins the caffeoyl-tartaric/p-coumaroyl-tartaric acid ratio is generally below 1 and the total flavonol concentration is around or below 100 mg/kg of berries (Di Stefano and Maggiorotto, 1995). GJ1 and BA-AL-132 berry skin polyphenols were less affected by the climatic conditions, as they accumulated similar quantities of total polyphenols, anthocyanins, flavonols, HCTA and HCA in the two years while the other examined clones showed a higher variability in the two years of trial. The malvidin-3-O-glucoside percentage was higher in the warmer year while in cooler 2002 its percentage content was reduced in favour of the delphinidin-3-O-glucoside percentage. The PCA model revealed that malvidin-3-O-glucoside percentage was negatively correlated with cyanidin-3-O-glucoside and delphinidin-3-O-glucoside percentages. The HCTA and the HCA concentrations showed a good level of positive correlation. The model used generally allowed a satisfactory clone separation and pointed out the significant year effect on the analysed polyphenol concentration.
Metabolic response of Vitis vinifera L. biotypes to climatic conditions
FERRANDINO, Alessandra;GUIDONI, Silvia;
2007-01-01
Abstract
Vitis vinifera ‘Barbera’ is the second red-grape variety for vineyard surface in Italy and the most widely cultivated (34 % of the total vineyards) in Piedmont (North-West Italy) where it is the base for VQPRD wines such as ‘Barbera d’Alba’, ‘Barbera d’Asti’ and ‘Barbera del Monferrato’. Fifteen clones have been selected and at present registered in Italy (AA.VV., 2005). In the present work the polyphenolic contents of clones of different origin were compared in the same environment. A PCA model was studied to reveal those variables which were highly correlated and which were able to differentiate clones. The trial was carried out in 2002 and in 2004 on vines planted in 1997, vertically trained and Guyot pruned. The vineyard, East-exposed and located in Monforte d’Alba (CN) was set in 3 randomised blocks of 5 vines each. At harvest berry skins of the studied clones (the registered clones AT-84, CVT 83, BA-AL-128, BA-AL-132, 17-BA, MI-B-34, PC-BA-26, MI-B-12 and the clones GJ1, GJ2, OB63 and OB66, under evaluation for possible homologation) were analysed for total anthocyanins and polyphenols by spectrophotometry and for anthocyanin profile, flavonols, hydroxycynnamoyl acid esters (HCTA) and free hydroxycinnamic acids (HCA) by HPLC (Di Stefano and Cravero, 1991). The two years of trial presented quite different meteorological conditions, 2002 being very fresh and wet with a total degree days (base 10°C) of 1653 °C and a total rainfall of 822 mm whereas 2004 was in the average, with a total degree days of 1773 °C and a total rainfall of 433 mm. ‘Barbera’ is a 3’,5’-substituted anthocyanin prevalent variety (delphinidin-3-glucoside, petunidin-3-glucoside and malvidin-3-glucoside together accounting for 70 % of the total anthocyanin content); the total acylated form percentages range from 12 to 20 %. In berry skins the caffeoyl-tartaric/p-coumaroyl-tartaric acid ratio is generally below 1 and the total flavonol concentration is around or below 100 mg/kg of berries (Di Stefano and Maggiorotto, 1995). GJ1 and BA-AL-132 berry skin polyphenols were less affected by the climatic conditions, as they accumulated similar quantities of total polyphenols, anthocyanins, flavonols, HCTA and HCA in the two years while the other examined clones showed a higher variability in the two years of trial. The malvidin-3-O-glucoside percentage was higher in the warmer year while in cooler 2002 its percentage content was reduced in favour of the delphinidin-3-O-glucoside percentage. The PCA model revealed that malvidin-3-O-glucoside percentage was negatively correlated with cyanidin-3-O-glucoside and delphinidin-3-O-glucoside percentages. The HCTA and the HCA concentrations showed a good level of positive correlation. The model used generally allowed a satisfactory clone separation and pointed out the significant year effect on the analysed polyphenol concentration.
I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
