Berlandieri x Riparia Group

420A

Origin: France (Millardet e de Grasset – 1887).

VEGETATIVE FEATURES

Leaf: medium-to-large, wedge-shaped, whole or with a hint of a three-lobed shape, hairless upper side, dark-green flap, bullous, with a V-U-shaped open petiolar sinus; the lower side is arachnoid, green, with light-green main ribs.

Woody shoot: long, branched, with prominent development of secondary shoots, elastic, hairless, of a bright brown-purple color.

CULTURAL APTITUDES

Ability to promote fruit setting:

good

Root system regeneration:

slow

Adaptability to soil type:

compact: good
wet: very poor
dry: good
stony: good
acidic: poor
saline: poor

Branching pattern of the roots:

taproot

Susceptibility to deficiencies or excesses:

deficiency of K: sensitive
deficiency of Fe: low sensitivity
deficiency of Mg: sensitive
deficiency of Zn: sensitive
deficiency of P: low sensitivity

Resistance to root phylloxera:

high

Resistance to leaf phylloxera:

good

Susceptibility to fungal and plant diseases:

downy mildew: low
powdery mildew: sensitive
anthracnose: sensitive
eutypa disease: it induces sensitivity
rachis desiccation: it induces moderate sensitivity

OTHER INFORMATION

- Behavior in the nursery: the rooting is good in combination with most grape varieties; however, it is not considered an easy-to-grow rootstock; it benefits from hormone treatments and mulching so to stimulate the rooting process.

Behavior in the propagation block: it is advisable to be grown on trellis, but it is also suitable to be grown sprawling on the ground; it tends to delay the entry into full production.

Behavior in the open field: it is not suitable to replanting; it induces differences in diametric growth at the grafting point; it restrains botrytis attacks and prolongs production capacity.