Table grape rootstocks in South Africa

US 8-7

Richter 99 x Jacquez Synonym(s): USVIT 8-7

Origin: Bred by Prof. C.J. Orffer, Stellenbosch University, in 1949

GENERAL CHARACTERISTICS Tolerances relating to: Phylloxera: Moderate. Nematodes: Moderately susceptible (2) to root-knot nematodes; moderate to dagger nematodes. Phytophthora : Unknown.

• Not widely used for table grapes. • No indications that demand is increasing.

CULTIVATION CHARACTERISTICS Compatibility: Reasonable (1) to moderate. Affinity: No problems known or observed in trials. Rooting: Not available. Vigour if not grafted: Moderate (1) . Vigour if grafted: Very good, but less vigorous than Ramsey and Dog Ridge in local trials. More inputs regarding canopy management practices of the scion cultivar are required than for most other rootstocks because of their strong vigour. Petiole nutrient status tendencies: High Ca uptake and low Mn uptake.

Crown gall: Unknown. Wet soils: Unknown. Dry soils: Moderate to good. Saline soils: Unknown. Calcareous soils: Unknown.

GENERAL: • Rootstock trials performed on loamy and sandy loam soils. • Long-term trial results showed production and quality performance of Crimson Seedless grafted to US 8-7 to be very good, but that of Regal Seedless only average.

32 Table Grape Rootstocks in South Africa