Characterization of grape phenolic compounds of 'Carignan' grapevines grafted onto 'País' rootstock from Maule Valley (Chile): Implications of climate and soil conditions
ABSTRACT Certain grape (Vitis vinifera L.) varieties overseen for decades by the Chilean wine industry have emerged as the 'Carignan'. 'País' has not had this resurgence and its production is sold for a price below the national average, negatively affecting the economy of small producers of the Maule Valley (Chile). The aim was to study the grape phenolic composition of 'Carignan' grapevines grafted onto 'País' rootstock according to climate and soil conditions. Sites were located in Valdivia (Val), Loncomilla (Lon), Melozal (Mel), and Huerta de Maule (Hdm) situated in Maule Valley. Phenolic compounds in grapes were analyzed by HPLC. The results showed that soil and climate conditions affected the accumulation of soluble solids, weight of 100 berries and most of the anthocyanins, flavonols and flavanols. Total anthocyanins content in grapes varied from 1393.05 to 1856.03 mg kg-1 (Val and Mel sites, respectively), while total flavonols content ranged from 124.17 to 218.93 mg kg-1 (Val and Lon, respectively). Total flavanols concentration varied from 86.85 to 158.13 mg kg-1 (Lon and Val), while total content of hydroxycinnamic acids varied from 23.91 to 34.84 mg kg-1 (Mel and Hdm). Location conditioned grape flavonoid composition of 'Carignan' grapevines grafted onto 'País'. The use of an ancient variety as a rootstock ('País') on a variety with a great oenological potential ('Carignan'), could be a viticultural tool to improve the income of the small wine-growers of the Maule Valley, without affecting phenolic composition in grapes.