Role of the variety and some environmental factors on grape stilbenes

V. vinifera L. 'Barbers', 'Croatina', 'Malvasia di Candia aromatica', growing in the Piacenza viticultural area (North-West Italy) at four elevations (150, 240, 320, 420 m a.s.l.), were tested at harvest for grape stilbene (traps-resveratrol, traps-piceid, cis-piceid) synthesis over three years (2000-2002). Meteorological data were recorded, as well as vine production and fruit quality parameters. The most significant findings were: (i) traps-piceid was the most abundantly produced stilbene compound (103 mu g center dot kg(-1) berry FW), while traps-resveratrol was the least produced (57 mu g center dot kg(-1) berry FW); (ii) 'Barbers' and 'Croatina' had similar traps-resveratrol berry levels (71 mu g center dot kg(-1) berry FW and 76 mu g center dot kg(-1) berry FW respectively), higher than 'Malvasia di Candia aromatics' (24 mu g center dot kg(-1) berry FW); (iii) 'Barbers' had the highest traps-piceid and cis-piceid concentrations (235 and 136 mu g center dot kg(-1) berry FW, respectively) while 'Malvasia di Candia aromatica' had the lowest levels (13 and 1 mu g center dot kg(-1) berry FW, respectively); (iv) stilbenes increased with elevation up to 320 m, while decreasing at the highest altitude; (v) the vintage year only significantly affected the cis-piceid berry concentration which was positively related to the relative humidity at the end of ripening, and negatively related to degree-days at the end of ripening.