Langjährige Beobachtung des Einflusses von 12 Unterlagsrebsorten auf die Edelsorte <i>Vitis vinifera L. cv</i> . Sauvignon blanc im Weinbaugebiet Südsteiermark

Abstract Long-term assessment of the influence of 12 grapevine rootstocks on the cultivar Vitis vinifera L. cv. Sauvignon blanc in the wine-growing region South Styria. The aim of this study was to examine the performance of the Sauvignon blanc variety grafted onto 12 different rootstocks in terms of phenology, vigour, stability, nutrient supply, grape quality, yield performance and must composition. After 19 years, vine losses were greatest in the rootstocks K5BB, 1103P, 3309C and 8B. Losses in the rootstock variety 161-49C (30%) were exclusively due to poor graft affinity and stunted growth. Minor differences were observed in the timing of bud break and no differences in the timing of flowering. After 19 years of growth, the significantly largest stem diameter was found in the trial variety 1103P (63 mm), while the smallest were detected in the varieties 3309C (49.6 mm) and 161-49C (51.0 mm). In four of the 12 varieties, rootstock suckers were observed. This was most common in 1103P, where suckers occurred on 40% of all vines. Significantly fewer suckers (all 5%) were found in the K5BB, SO4 and Ganzin 9 varieties. The macro-nutrient contents in the dry matter of the leaf blades differed significantly in phosphorus, potassium, calcium and magnesium. The highest phosphorus contents were found in the rootstock varieties 5C (0.33%) and Fercal (0.32%), and the lowest in 3309C (0.22%), 161-49C (0.23%), Börner (0.23%), 8B (0.24%), SO4 (0.25%) and Binova (0.26%). The highest potassium content was provided by SO4 (1.21%), while the variants 420A (0.99%), Fercal (1.01%), 1103P (1.03%) and Ganzin 9 (1.06%) were significantly lower. Significantly higher leaf calcium contents were found in the variants 1103P (2.35%), 420A (2.29%) and Fercal (2.25%). The highest magnesium contents in the leaf blades were measured in the variants 1103P (0.25%) and Fercal (0.2%). Significant differences in the micronutrient content in the leaf blades were only found for copper and zinc. The highest copper contents were measured in the trial varieties Ganzin 9 (14.5 mg/1000 g), Fercal (12.8 mg/1000 g) and 1103P (11.2 mg/1000 g). For zinc, the rootstock 161-49C trial variant with the highest content (33.7 mg/1000g) differed significantly from the Binova variant (20.6 mg/1000g) with the lowest content. The highest average yields per vine were achieved with Fercal (3.98 kg), 1103P (3.97 kg) and 420A (3.95 kg) varieties, while the lowest yields were recorded for the 3309C (2.83 kg) and 161-49C (1.60 kg) rootstock varieties. The highest cluster weights were achieved by 5C (169 g), 1103P (167 g) and Fercal (166 g), which differed significantly from K5BB (153 g), Börner (152 g), 3309C (142 g), Ganzin 9 (140 g) and 161-49C (111 g). Analysis of the grape musts revealed a significant difference in calcium concentration between 161-49C (72.0 mg/l), which showed the highest, and 1103P (58.2 mg/l), with the lowest. Rootstock 161-49C tended to produce the lowest total acidity in the must, while Börner, Ganzin 9, 3309C and 8B tended to have lower NOPA and NH4 + values.