SO 4
| Variety Passport | |
| Country of origin: | Germany |
| Breeder: | Zsigmond Teleki, Heinrich Fuhr |
| Variety number VIVC: | 11473 |
| Prime name: | Selektion Oppenheim 4 |
| Breeding number: | SO 4 |
| Principal Synonyms: | Selection Oppenheim 4, Oppenheim So4, Berlandieri X Riparia So4 |
| Year of obtaining / registration: | obtained in 1896 |
| Pedigree given by breeder: | Obtained In 1896 |
| Pedigree confirmed by markers: | Berlandieri Resseguier 2 x Gloire de Montpellier |
| Rootstock type: | Phylloxera-resistant, Nematode-resistant, Acid-soil tolerant, Salt-tolerant |
| Data Sources: | Vitis International Variety Catalogue (VIVC), INRAE (France) |
| Agrobiology | |
| Vigor: | vigorous |
| Lateral shoot formation: | weak |
| Flower type: | male |
| Active lime tolerance: | 17% |
| Salinity tolerance: | resistant |
| Drought tolerance: | resistant |
| Waterlogging tolerance: | low |
| Nematode susceptibility: | 2 points (resistant) |
| Root phylloxera susceptibility: | 1 point (highly resistant) |
| Rooting ability: | high |
| Graft compatibility with Vitis vinifera: | high |
| Recommended soil types: | 1. Sandy soils (provided that the magnesium deficiency is corrected), plains terroirs and clay-limestone soils that are moderately or not very fertile, as well as acidic soils. |
| Ampelographic overview |
History of Origin and Agronomic Importance
The grape rootstock SO 4 was obtained in 1896 by breeders Sigmund Teleki and Heinrich Fuhr through the crossbreeding of Vitis berlandieri and Vitis riparia forms derived from Euryale Rességuier. In France, this variety covers an estimated surface area of approximately 180,000 hectares and is found across all French wine-growing areas. The variety exhibits a high tolerance to the root form of phylloxera. Its resistance to Meloidogyne incognita and Meloidogyne arenaria nematodes is also very good, while it remains moderately tolerant to Meloidogyne hapla. This vine is well suited to acidic and sandy soils and is fairly tolerant to chlorides. However, it poorly absorbs magnesium, which can promote the dessication of the stems. The radial trunk growth of this rootstock is very limited, creating a "thin leg" effect with substantial diameter differences compared to the grafts, which determines the requirement for trellising. The vigor conferred to the grafts is strong, particularly during the first 15 years of the vine's life. The grafted plants produce high yields from the first years after planting, which sometimes requires cluster thinning. It induces good sugar content in the fruits, but the resulting wines often lack body and can sometimes express herbaceous notes and high pH levels due to the elevated yields.
Ampelographic Description of the Rootstock Variety SO 4
The identification of the variety SO 4 is based on the following ampelographic characteristics:
- Young shoot tip (cleft): half opened, with a piping anthocyanin coloration and a medium density of prostrate hairs.
- Young leaves: characterized by a distinct bronzed appearance.
- Shoots: elongated, with a ribbed surface and a slightly elliptic section. The nodes are shiny red, and the internodes show reddish spots on the ventral side. Erect and prostrate hairs are completely absent.
- Tendrils: divided into three parts (trifid).
- Adult leaf: large in size, wedge-shaped, and involute. The leaf blade is undulate between the veins. The petiole sinus is open, forming a U- or V-shape. The marginal teeth feature straight sides. The anthocyanin coloration of the veins is weak. On the lower side of the leaves, the density of erect hairs is low to medium.
- Inflorescences: the variety develops male flowers.
- Woody shoots: the mature woody canes have a dark brown coloration.
Propagational Features in Nursery Management
The grape rootstock SO 4 provides a very good wood production yield, reaching 60,000 to 100,000 meters per hectare of mother vines, though a certain proportion of dry canes can sometimes occur. The variety responds well to fertilization and irrigation, but the canes complete their lignification fairly late in the season. The rootstock SO 4 exhibits very good cutting and grafting capacities, and its canes are easy to clean and disbud due to the limited growth of lateral shoot buds. The internodes feature a medium-size diameter. When utilized, hormone treatments should be moderate, and the total duration of the stratification process may sometimes require longer periods.