Evaluation of different rootstocks for grapevine in south Brazil: nutritional, yield, and qualitative aspects

The potential for quality winegrape production in southern Brazil is hampered by the lack of rootstock information to control vine vigor on soils that result in high vegetative growth. This two-year trial carried out in southern Brazil (EPAGRI Experimental Station of Sao Joaquim - SC) compares different rootstocks and evaluates the behavior of vines grafted with 'Sauvignon Blanc'. Measurements assess vine vigor, nutritional status, yield, and quality with the aim to enhance knowledge about the choice of rootstocks for Brazilian viticulture. Ten different rootstocks 101-14 Mgt, 3309 C, 110 R, 99 R, 1103 P, Kober 5BB, SO4, 420A Mgt, Gravesac, and IAC 766 were replicated four times in plots composed of six vines. Starting at the end of 2018, two years after planting, vigor measures as the weight of pruned material and shoot length, SPAD levels, nutrient concentration of leaves and petioles were collected at full bloom and at veraison. Productivity and quality parameters including yield, clusters, pruning weights, soluble solids, pH and total acidity were also measured. The rootstocks IAC 766 and Gravesac conferred greater vegetative development (both for shoot length and weight of pruned material) than 420A Mgt and 110 R, which had the lowest productivity but the highest concentration of soluble solids. However, the highest yields were observed in plants grafted on 1103 P, Kober 5BB, and 3309 C. SPAD values of plants grafted on IAC 766, 3309 C, Kober 5BB, and Gravesac were significantly higher than those of 110 R, 1103 P and 99 R. K/Mg ratio and potassium content in both leaves and petioles were significantly lower in 420A Mgt. Magnesium levels in both tissues were strongly affected by rootstocks. Plants grafted on 1103 P and 99 R had higher values compared with 3309 C and Gravesac. Boron absorption significantly increased when 101-14 Mgt, 1103 P, and 3309 C were used. According to qualitative parameters, 'Sauvignon Blanc' grafted on all evaluated rootstocks produced grapes suitable for the production of quality wines.