Table grape rootstocks in South Africa

DOG RIDGE

V. champini (a natural crossing) Synonym(s): Dogridge

Origin: Discovered by T.V. Munson on Dog Ridge mountain, Texas, USA, in 1900

GENERAL CHARACTERISTICS Tolerances relating to: Phylloxera: Moderate. Nematodes: Good against root-knot nematodes; susceptible to dagger and ring nematodes (2) . Phytophthora : Very good. Crown gall: Unknown. Wet soils: Very good. Dry soils: Very good (1) . Saline soils: Good to very good. Calcareous soils: Very poor to moderate, depending on the quantity of free lime in the soil.

White cultivars, performs as well as and sometimes better than Ramsey, especially on sandy soils.

CULTIVATION CHARACTERISTICS Compatibility: Weak; grafts with difficulty. Affinity: No problems known or observed in trials. Rooting: Poor; should be treated with rooting hormones. Vigour if not grafted: Very strong to excellent. Vigour if grafted: Very strong; vines can be developed fully within the first year. Costs of canopy management practices higher than with other rootstocks due to vigorous growth. Petiole nutrient status tendencies: High P, Ca, Mg and B uptake (1) .

GENERAL: • Performance in trials mostly and sometimes even better than Ramsey, especially with white cultivars. • Induces strong vigour in scions and is usually associated with good to excellent quality table grapes with most scion cultivars and in a wide spectrum of soils. • With inherently vigorous scion cultivars, it may sometimes result in problems regarding fertility, as well as colour development problems with red and black cultivars in very fertile soils.

36 Table Grape Rootstocks in South Africa