Oppenheim Selection 4
Genetic origin
This variety results from a cross between Vitis berlandieri and Vitis riparia from Euryale Rességuier.
Identification is based on the following traits:
– The young shoot tip is half-open, with anthocyanin pigmentation along the edges and a medium density of prostrate hairs.
– Young leaves are bronzed.
– Herbaceous shoots are elongated, with a ribbed contour, slightly elliptical cross-section, shiny red nodes and internodes with reddish spots on the lower side, and no upright or prostrate hairs.
– Tendrils are trifid (split into three branches).
– Mature leaves are large, wedge-shaped, involute, with a wavy blade between veins, an open U- or V-shaped petiolar sinus, straight-sided teeth, weak anthocyanin pigmentation on veins, and a low to medium density of upright hairs on the underside.
– Flowers are male.
– Shoots are dark brown in color.
SO4 has a high level of tolerance to root phylloxera. It also shows strong resistance to Meloidogyne incognita and Meloidogyne arenaria nematodes. Its tolerance to Meloidogyne hapla is moderate.
SO4 tolerates up to 35% total limestone, 17% active limestone, and an IPC (chlorosis risk index) of 30. Its resistance to iron chlorosis is thus considered moderate. It performs well in acidic soils and has fairly good tolerance to chlorides. Drought resistance ranges from moderate to good, but it shows low to moderate adaptation to excessive moisture and can be sensitive to tylosis. SO4 absorbs magnesium poorly and may increase the risk of rachis desiccation. It is well suited to sandy soils (provided magnesium deficiency is corrected), flat terroirs, and moderately to low-fertility clay-limestone soils. However, it is poorly adapted to very dry, chlorosis-prone, or overly compact soils.
In general, SO4 is highly compatible with most scion varieties, but radial trunk growth is limited. It is said to have a “thin leg”, meaning a significant diameter difference may occur with the scion, requiring support staking. Grafted vines on SO4 develop rapidly, and it imparts strong vigor to the scion, especially in the first 15 years of the vineyard’s life. SO4 enables high yields early after planting, sometimes requiring thinning. It promotes good sugar accumulation, but the resulting wines often lack body and may show herbal notes due to high yields. It also tends to produce wines with higher pH levels.
SO4 is a very good wood producer (60,000 to 100,000 meters/ha), although some dry wood may be present. It responds well to fertilization and irrigation, but lignification of the wood is relatively late. It has excellent rooting and grafting ability and is easy to de-bud. Its internodes are of medium diameter and shoot regrowth is limited. If used, hormone treatment should be moderate, and stratification may require slightly more time.