Abstract
Twenty grapevine genotype of diverse hybrid origin (‘Chancellor’, ‘Delisle’, ‘ES-6-12-28’, ‘ES-4-7-25’, ‘GR-7’ ‘Hibernal’, ‘Sabrevois’, ‘Kay Gray’, ‘Lucie Kuhlmann’, ‘Michurinetz’, ‘Okanagan Riesling’, ‘Prairie Star’, ‘St. Croix’, ‘St. Pepin’, ‘Seyval noir’, ‘Seyval blanc’, ‘SV-18-307’, ‘Vandal-Cliche’ and ‘Vidalblanc’)andonevmf/era (’Siegerrebe’) were evaluated under different winter protection methods where twelve hardy and semi-hardy genotypes received 3 treatments: seven tender genotypes received one treatment and only one tender genotype received 2 treatments [vines without protection: (Ml)]; pinning half of the canes to the ground allowing for natural snow cover protection and the remaining canes left attached to the trellis wires without protection (M2); vine removed from the trellis, laid down and covered with geotextile fabric (M3) or soil (M4) at three locations in Quebec (Canada) differing in soil type and microclimate conditions. The effects of these methods on annual production, winter resistance and vegetative growth were measured. Total yield for all genotypes at Frelighsburg were 3 and 4 times higher than at L'Orpailleur (Dunham) and Dietrich-Jooss (Iberville) commercial vineyards, respectively. For protection system Ml and M2, the highest yields were recorded for ‘Vandal-Cliche’ and ‘St. Croix’ followed by ‘ES-4-7-25’ and ‘St. Pepin’. The M3 treatment was the most effective protection for some semi-hardy genotypes. Under M3 protection average yield of semi-hardy genotypes remained higher (6 and 4 kg) than that of the hardy genotypes (3 and 1.7 kg) at L'Orpailleur and Dietrich-Jooss (2000), respectively. ‘Seyvalnoir’, ‘Seyvalblanc’, ‘Chancellor’, ‘Vandal-Cliche’, and ‘ES-4-7-25’ exceeded 20 kg under M3 treatment. M4 protection for ‘Seyval blanc’ was not effective resulting in decreased yield, vigour and increased mortality. Higher bud survival levels were observed at Frelighsburg for hardy genotypes such as ‘Sabrevois’, ‘St. Croix’, ‘Kay Gray’, ‘Vandal-Cliche’, ‘St. Pepin’ and ‘Michurinetz’ under all protection treatments. In commercial vineyards, greater than 50% bud mortality was observed for semi-hardy genotypes ‘ES-6-12-28’, ‘GR-7’ and ‘Lucie Kuhlman’, with even higher mortality in tender genotypes ‘Siegerrebe’, ‘Vidal blanc’ and ‘SV-18-307’. The highest vigour was achieved in hardy and moderately hardy cultivars while the tender cultivars were less vigorous at all three sites and over both years. Site location was the most important factor affecting vine yield and mortality, with the best performances being recorded at Frelighsburg. This is assured due to the site in Frelighsburg having a slight south slope very well drained sandy soil, and excellent snow accumulation.