1- SO4: Selection Oppenheim 4
The SO4 pattern has been imposed in recent years in many wine-growing areas in northern Spain , but not in the rest of Spain, as its adaptation to dry soils is poor.
Its main characteristic is that it supports excess humidity well . In France and cool areas it has been considered the most important rootstock.
2- Usual name
3- Sorters , breeders
Sigmund Teleki y Heinrich Fuhr
4- Year of obtaining
5- Genetic origin
Cross of Vitis berlandieri and Vitis riparia
6- Resistance to soil parasites
SO 4 has a high resistance to root phylloxera.
Likewise, its resistance to the nematodes Meloidogyne incognita and Meloidogyne arenaria is very good.
Its degree of resistance to the nematodes Meloidogyne hapla is medium.
It is generally considered to have good resistance to nematodes.
7- Adaptation to the environment
- SO 4 resists up to 35% total limestone and 17% active limestone. CPI 30.
- Its resistance to iron chlorosis can be considered average.
- In some places, it performs well in acid soils and its tolerance to chlorides is quite good.
- Its resistance to drought is medium.
- Its adaptation to excess humidity is medium-high.
- The SO 4 poorly absorbs magnesium and favors the drying phenomenon of the stalk.
- Its use is interesting in sandy soils (thinking that we will have to make magnesium corrections), argilocalcareous soils with medium or low fertility.
- It is poorly adapted to very dry , chlorotic and very compact soils.
8- Interaction with the variety and production objectives
- In general, SO 4 shows good compatibility with the grafts, but the radial growth of the trunk is very limited.
- For this reason, there may be an important difference in diameter between the rootstock and the variety and it is necessary to use a trellis.
- The development speed of the plants grafted with SO 4 is very high and the vigor that this rootstock confers on the plants is considered strong during the first part of the life of the vineyard (first 15 years).
- It allows to obtain high yields and in the first years after planting it needs clusters thinning.
- It favors fruiting and advances ripening as long as it does not have a high load.
- It transfers good levels of sugars , but the wines obtained often lack body and have herbaceous notes due to the high yields.
- SO 4 also favors obtaining high pH wines .