Vitis vinifera ‘Ráthay’ on the rootstocks ‘Kober 5BB’, ‘Fercal’, and ‘3309 C’: results of a long-term field trial

Abstract

Context and purpose of the study. Ráthay is an Austrian red quality wine variety with increased resistance to fungi. However, little is known about the effect of rootstock varieties on vigour, yield and grape quality of Ráthay. The aim of the present study was to analyse the influence the three rootstock varieties ‘Kober 5BB’, ‘Fercal’ and ‘3309 C’ on yield, cluster weight, must weight, titratable acidity and pH-value of the must, pruning wood weight, nutrient content of leaves and the lifespan of the vines.

Material and methods. The grafted vines were planted in 1997 at a spacing of 2.0 x 1.0 metres and raised in a medium-high trellis training system with a tying wire (h = 0.85 m), a cordon wire (h = 0.89 m) and three stitching wire pairs (h = 1.25 m, 1.55 m and 1.95 m). Pruning was carried out as follows: one fruit cane with seven to nine buds and one spur with two buds (= single Guyot). Thus, the number of buds per vine was 9 to 11 or the equivalent of 4.5 to 5.5 buds per m². The trial vineyard was located on a steep slope (gradient: 40 to 50 %) facing southeast. The soil type was a carbonate-containing brown soil on flysch marl. The parent rock is flysch marl, a marine sedimentary rock consisting of limestone and clay. The soil has a pH-value of 7.4 and is slightly alkaline. Lime content in the A- and B-horizons is high (23 to 25 %) and active lime is medium (15 to 20 %). The soil has an average humus content of 3.0 % in the topsoil. It is a heavy soil with a clay content of 28 – 30 %. Yield, cluster weight, must weight and titratable acidity and pH-value in the must were determined for ‘Ráthay’ in the form of four replicates per graft combination (10 to 20 vines per replicate) over 22 years. Pooled samples from five vines per repetition were analysed. Beery samples were taken immediately before harvest to determine the maturity parameters. The pruning wood weight was determined after pruning according to the experimental design. In twelve years, leaves were removed from the grape zone in July, dried, ground and the contents of nitrogen, potassium, magnesium, phosphorus, calcium, iron, copper, zinc, manganese and boron were analysed. By the 25th year of growth, the number of vines that had failed by then was evaluated depending on the grafting combination.

Results. Yield was significantly lower on ‘3309 C’ than on ‘Kober 5BB’. Cluster weight was significantly higher on ‘Kober 5BB’ than on ‘Fercal’ and ‘3309 C’. With must weight and pH-value of the musts there were no significant differences between the graft combinations. Titratable acidity in the must was significantly higher on ‘Kober 5BB’ than on ‘3309 C’. Pruning wood weight was significantly lower on ‘3309 C’ than on the other two rootstock varieties. Potassium content of the leaves was significantly lower on ‘Fercal’ than on ‘3309 C’ and magnesium content was significantly lower on ‘Kober 5BB’ than on ‘3309 C’ and ‘Fercal’. Calcium content of the leaves was significantly lower on ‘3309 C’ than on ‘Fercal’ and ‘Kober 5BB’ and phosphorus content was significantly lower on ‘3309 C’ than on ‘Kober 5BB’. The contents of nitrogen, iron, copper and zinc in the leaves of Ráthay were not influenced by the rootstock varieties. Manganese content of the leaves was significantly lower on ‘Kober 5BB’ and ‘3309 C’ than on ‘Fercal’ and the boron content was significantly lower on ‘3309 C’ than on ‘Fercal’. By the 25th year of growth with ‘Kober 5BB’ 19.0 %, with ‘Fercal’ 21.9 % and with ‘3309 C’ 28.8 % of the vines had failed. The main reason for the dieback of the vines was an increasing incidence of Esca with vine age. Furthermore a high incidence of chlorosis was triggered by ‘3309 C’, which increased the number of dead vines.