Compatibility of Rootstock Börner with Various Wine- and Table-Grape Varieties

Compatibility ORIGINAL SCIENTIFIC of Rootstock PAPER Börner with Various Wine- and Table-Grape Varieties Compatibility of Rootstock Börner with Various Wine- and Table-Grape Varieties Stanko VRŠIČ, Borut PULKO, Janez VALDHUBER University Centre of Viticulture and Enology Meranovo, Faculty of Agriculture and Life Sciences, Pivola 10, 2231 Hoče, Slovenia, (e-mail: stanko.vrsic@um.si) Abstract The compatibility of Börner rootstocks with various wine- ( Furmint, Regent, Riesling, Sauvignon Blanc, and Welschriesling ) and table-grape ( Muscat Bleu, Ester, and Nero ) varieties, used as scions, were investigated in 2005 and 2006. The Börner rootstock was compared to the most prevalent rootstocks ( and ) in Slovenia. A randomised, complete block design was used (four replicates, 50 grafted plants per replicate). At the time of forcing, the differences in callus development were greater between the years than between rootstocks, which were the most obvious in the Furmint wine-grape variety. In 2006 there were 24% more grafts with a fully developed callus than in 2005. Due to poorer wood maturity (e.g. in 2004) callus of this late-ripening variety was less developed. In 2006, for most varieties, the average percentage of the first grade grafted vines was higher when the rootstock was used. In our experimental conditions (loamy soil) the grafted vines on the Börner rootstock had fewer roots and they were thinner. Key words: grafted vine, rootstock, compatibility, Börner Introduction The grafting of European grapevine (Vitis vinifera L.) varieties onto rootstocks (hybrids of the American Vitis species) is still considered to be the most effective way of protection against phylloxera (Daktulosphaira vitifoliae Fitch), a world-wide pest of grapevines (Granett et al., 2001). The Phylloxera develops more aggressive biotypes which overcome the resistance of some rootstocks (Granet et al., 2005), and damage due to phylloxera increases (Martinez-Peniche, 1999). At the end of the nineties in Germany several vineyards were replanted with vines grafted on the Börner rootstock, which was selected from the hybrid progeny derived from crossing V. riparia 183 Gm V. cinerea Arnold (Korosi, 2011). The Börner rootstock is less tolerant to the heavy soils and lime-induced chlorosis (Pavloušek, 2009). When breeding and selecting rootstocks for certain site conditions not only the resistance to phylloxera, but also their affinity and compatibility, growth intensity (Pavloušek, 2010), vigour (Pellegrino et al., 2005), adaptation to soil (Tarricone et al., 2011), and climatic conditions are of great importance (Patil et al., 2005; Pavloušek, 2011; Vršič et al. 2014). In young grafted grapevines, the scion has a major effect on the biomass accumulation in the shoot, as well as the root system. Also the rootstock has a significant effect on root development (Vršič et al. 2015). In grafted vines, the root development and healing of the graft union were particularly affected by the water content and carbohydrates stored in the canes used for scions and rootstocks (Vršič et al., 2009). The mechanism of graft incompatibility is not yet fully understood. The X-ray tomography technique used to evaluate graft quality showed that the good grafts had tissues well connected in the wood and phloem, and had a regular structure (Milien et al., 2012). The main objective of this study was to investigate the compatibility of various wine- and table-grape varieties with different rootstocks, with special emphasis on the Börner rootstock. Proceedings. 51 st Croatian and 11 th International Symposium on Agriculture. Opatija. Croatia (409-413) Section 8. Viticulture and Enology 409

Stanko VRŠIČ, Borut PULKO, Janez VALDHUBER Material and methods The wine grape varieties Welschriesling, Furmint, Riesling, Sauvignon Blanc, and Regent and the table grape varieties Muscat Bleu, Ester, and Nero were grafted on,, and Börner rootstocks in 2005 and 2006. The canes of scions and rootstocks were collected in the collection vineyard at the University Centre of Meranovo, Faculty of Agriculture and Life Sciences, in Slovenia. Prior to grafting, the cane of rootstocks and scions were desinfected by Chinosol W (0.5% solution) and kept in plastic bags at 2 o C. In total, 200 scions of each variety were grafted onto each rootstock. Grafts were callused in moist sawdust at a temperature of 26 28 C, and with humidity of about 80%. The grafted vines were left in water for 24 hrs and then planted in a trial based on a randomised, complete block design (with four replicates, 50 grafts per replicate) in the ridges covered with black polyethylene foil. The trials were conducted in a commercial nursery near Ptuj (4646' N, 1581' E, 280m AMSL) in NE Slovenia. The soil was medium deep loamy, with a ph 6.11 (0.1 mol/l KCl). Based on the ammonium lactate extraction procedure, the soil contained 152 mg P, 289 mg K, and 135 mg Mg per kg of air-dried soil from a soil layer of 0-30 cm. The soil samples were taken before the start of the trial. Fertilizers were not applied during the experimental period To evaluate the compatibility of the grafted units was analysed by the degree of callus development and the percentage of first grade grafted vines (Council Directive 68/193/EEC and Offi-cial Gazette of RS, no. 93/05). After the forcing period, the grafted vines were divided into three groups: (1) vines with a completely developed callus; (2) vines with a partially developed callus; and (3) vines without a callus. After digging up the plants, we checked the healing of the grafted place and determined root growth. The first grade grafted vines had at least three equally developed roots which were thicker than 3mm (the accepted minimum; Official Gazetteof RS, no. 93/05). For the statistical analysis of the data, the programme SPSS 19.0 was used (ANOVA analysis of variance, p <0.05). Results and discussion In general, in 2006 the percentage of grafted vines with a completely developed callus was on average 24% higher than in 2005 in all rootstocks (20% in, 22%, and 29% in Börner ). The highest increase on average was determined for Furmint (40%). The average percentage of grafts in 2005, with a completely developed callus was 11% higher when using (in comparison to Börner ), except for Sauvignon Blanc, Regent, and Muscat Bleu, where no significant differences were established. The greatest differences among rootstocks were observed on Riesling (14%) grafted onto the and Börner rootstocks. The significant difference between and was observed only in the Nero table grape variety. In 2004, the weather conditions for wood maturation were not optimal, and this was reflected in the callus formation in 2005 (Tab. 1). Furmint was characterised by the highest percentage of grafted vines with a partly developed callus in all rootstocks (on average 45%). This can be considered as typical for this variety, especially in years when weather conditions are not suitable for wood maturation (e.g. in 2004). After forcing in 2006, the average percentage of grafted vines with completely overgrown callus was 83%. Differences between the and Börner rootstocks (Table 1) were significant only in Regent, Sauvignon Blanc, and Muscat Bleu varieties. Sauvignon Blanc and Muscat Bleu had a higher percentage of grafted vines with a completely overgrown callus on the Börner rootstock, which was not reflected later on the percentage of first grade grafted vines in the nursery. The differences between the rootstocks in the average percentage of the first grade grafts were more consistent in table grape varieties (Fig.1). The percentage was significantly higher in both years, when the rootstock was used. In wine varieties (Fig.2) the percentage was higher at the rootstock only in Furmint. Regent had the highest percentages on the Börner,while in other varieties the differences between the rootstocks were not significant in 2005. The percentages of the first grade grafts varied from 52% in Regent to 67% in the table grape variety Nero, both on the rootstock. The average percentage of first grade grafted vines (of all studied varieties) was 60%, and ranged from 58.4% in Börner to 61.7% in. 410 51 st Croatian and 11 th International Symposium on Agriculture

Compatibility of Rootstock Börner with Various Wine- and Table-Grape Varieties Table 1. Callus development of the wine- and table grape variety on the rootstocks,, and Börner () after the forcing in 2005 and 2006. Variety Rootstock Callus 2005 Callus 2006 Complete Partial Without Complete Partial Without 52a 44 4 88a 8 4 50a 42 8 88a 4 8 Furmint 43b 49 8 90a 8 2 58a 38 4 72b 20 8 60a 32 8 70ab 24 6 Sauvignon 62a 30 8 80a 16 4 64a 12 24 80a 14 6 62a 20 18 78a 14 6 Regent 58a 20 22 68b 24 8 70a 20 10 84a 8 8 62ab 22 16 82a 18 0 Riesling 56b 32 12 88a 10 2 68a 30 2 88a 10 2 62ab 36 2 84a 14 2 Welschriesling 58b 34 8 88a 12 0 66a 30 4 86a 14 0 62a 34 4 84a 12 4 Ester 56b 34 10 88a 10 2 64a 34 2 80b 14 6 62a 32 6 86ab 10 4 Muscat bleu 58a 38 4 90a 8 2 68a 22 10 90a 10 0 58b 32 10 84a 12 4 Nero 56b 22 12 86a 12 2 Note: different letters indicate significant differences between the rootstocks in each variety; p 0.05. In 2006, the differences between the rootstocks were consistent in all varieties and average percentage varied from 62% in Riesling on the to 86% in Welschriesling on (Fig.2). The differences between and Börner were significant in all varieties, except in Furmint. In 2006, the average percentage was higher by 13.5% (it was 73.5%), and it varied from 70.6% in Börner to 78.4% in. In the case of Börner, the average percentage of the first grade grafts of all varieties was lower in both years, 58.4% in 2005 and 70.6% in 2006. The main reasons were the probably a lower number and thinner roots of Börner. Section 8. Viticulture and Enology 411

Stanko VRŠIČ, Borut PULKO, Janez VALDHUBER Figure 1. Average percentage of first grade grafted vines of table grape variety of the rootstocks,, and Börner in 2005 and 2006 (different letters indicate significant differences between the rootstocks in each variety; p 0.05). Figure 2. Average percentage of first grade grafted vines of wine variety of the rootstocks,, and Börner in 2005 and 2006 (different letters indicate significant differences between the rootstocks in each variety; p 0.05). Conclusion Our results show that the compatibility of the Börner rootstock with the wine and table grape varieties was similar to and rootstocks, which are most prevalent in Slovenia. The differences in callus development were greater between the years than between rootstocks. Less suitable weather conditions (e.g. 2004) influenced poorer wood maturity (cane for scions), and was reflected in the callus development in 2005. This was most obvious in the Furmint wine-grape variety. Furmint was characterised by having the most grafts with a partly developed callus in all rootstocks, which can be considered as typical for this lateripening variety. The root development and healing of the graft union are particularly affected by the water content and stored reserves (mainly carbohydrates) in the canes (Vršič et al., 2009). The differences in callus development between the years were confirmed the existence of 24% more grafts with a completely overgrown callus in 2006 than in 2005. The differences were more consistent in both years in the table grape varieties, which ripen earlier and where the wood maturity was more appropriate. This was also the case in the year with less favourable weather conditions. 412 51 st Croatian and 11 th International Symposium on Agriculture

Compatibility of Rootstock Börner with Various Wine- and Table-Grape Varieties In our experimental conditions (heavier soil) it was also found that the grafts on the Börner rootstock had fewer roots and they were thinner. This resulted in less carbohydrate accumulation in the grafts, which may affect the growth of grafts in the first year in the vineyard. Due to resistance against phylloxera and tolerance to viruses which are transmitted by nematodes (Blank et al., 2009), the Börner rootstock is suitable for stock plantations to produce scions. In this way, the reinfection of vines in newly planted vineyards can be reduced. It promotes the biological defence system in the areas infected by phylloxera and nematodes. References Granett, J, L. Kocsis, L. Horvath and E. B. Horvathne (2005). Grape Phylloxera Gallicole and Radicicole Activity on Grape Rootstock Vines. Hortscience, 40: 150-153. Granett, J, M. A. Walker, L., Kocsis and A. D. Omer (2001). Biology and Management of Grape Phylloxera. Annual Review of Entomology, 46: 387-412. Korosi, G. A, K. S. Powell, P. R. Clingeleffer, B. Smith, R. R. Walker and J. Wood (2011). New Hybrid Rootstock Resistance Screening for Phylloxera under Laboratory Conditions. Acta Horticulturae, 904: 53-58. Martinez-Peniche, R. (1999). Effect of Different Phylloxera (Daktulosphaira vitifoliae Fitch) Populations from South France, upon Resistance Expression of Rootstocks 41 B and Aramon x Rupestris Ganzin No. 9. Vitis, 38: 167-178. Milien, M, A. S. Renault-Spilmont, S. J. Cookson, A. Sarrazin, J. L. Verdeil (2012). Visualization of the 3D structure of the graft union of grapevine using X-ray tomography. Scientia Horticulturae, 144: 130-140. Patil, S. G, S. P. Karkamkar and M. R. Deshmukh (2005). Screening of grape varieties for their drought tolerance. Indian Journal of Plant Physiology. 10: 176-178. Pavloušek, P. (2009). Evaluation of Lime-induced Chlorosis Tolerance in New Rootstock Hybrids of Grapevine. European Journal of Horticultural Science, 74: 35-41. Pavloušek, P. (2010). Lime-induced chlorosis and drought tolerance of grapevine rootstocks. Acta Universitatis Agriculturae Et Silviculturae Mendelianae Brunensis, 58: 431-440. Pavloušek, P. (2011). Evaluation of drought tolerance of new grapevine rootstock hybrids. Journal of Environmental Biology, 32: 543-549. Pellegrino, A, E. Lebon, T. Simmoneau and J. Wery (2005). Towards a simpleindicator of water stress in grapevine (Vitis vinifera L.) based on thedifferential sensitivities of vegetative growth component. Australian Journal of Grape and Wine Research, 11: 306-315. Tarricone, L, G. Masi, G. Gentilesco and A. M. Amendolagine (2011). Effects of Rootstock on Nursery Performance of Seedless Table Grapes. Rivista di Viticoltura e di Enologia. 64: 73 81. Vršič, S, B. Pulko and J. Valdhuber (2009). Influence of Defoliation on Carbohydrate Reserves of Young Grapevines in the Nursery. European Journal of Horticultural Science, 74: 218-222. Vršič, S, V. Šuštar, B. Pulko and T. Kraner Šumenjak (2014).Trends in climate parameters affecting winegrape ripening in northeastern Slovenia. Climate Research, 58: 257-266. Vršič, S., B. Pulko and L. Kocsis (2015). Factors influencing grafting success and compatibility of grape rootstocks. Scientia Horticulturae 181: 168 173. sa2016_p0807 Section 8. Viticulture and Enology 413