Rootstocks

Question 1

Using examples, explain how adaptability to Soil pH can influence a grape-grower’s choice of rootstock:

Answer 1

Certain rootstocks are more tolerant of very low (acidic) or high (basic) pH levels.

e.g. Hybrids of V. rupestris X V. berlandieri e.g. 99R = tolerant of acidic soils.

V. berlandieri e.g. 41B = tolerant of high lime content (high pH soils.)

Question 2

Using examples, explain how adaptability to Vigor can influence a grape-grower’s choice of rootstock:

Answer 2

Vigor = tendency to grow a lot of shoots/vegetation.

Low vigor rootstocks = better in cool climates (because low temps encourage vegetative growth.) e.g. V. riparia such as 420A = low vigor.

High vigor rootstocks = better in unfertile, dry conditions or for sparkling wine production, e.g. V. rupestris such as 140R = high vigor.

Question 3

What are 4 factors that might influence a grape-grower’s choice of rootstock?

Answer 3

1. Resistance to Pests
2. Water / Drought Tolerance
3. Soil pH
4. Vigor

Question 4

Using examples, explain how adaptability to Water can influence a grape-grower’s choice of rootstock (3):

Answer 4

• Hybrids of V. rupestris and V. berlandieri e.g. 110R = tolerant to drought (ability to root deeply / quickly.)
• V. riparia e.g. Riparia Gloire = tolerant of water-logged soils.
• V. berlandieri e.g. 1103 Paulsen = tolerant of salinity.

Question 5

What is the advantage / disadvantage of a grape-grower replacing existing vines via head grafting?

Answer 5

Advantage: Established root system allows new vine to produce fruit much sooner.

Disadvantage: Specific traits of the rootstock might be more suitable for previous varietal than the new one.

Question 6

Using examples, explain how adaptability to Pests can influence a grape-grower’s choice of rootstock:

Answer 6

• Phylloxera-Resistant rootstocks are almost universally used.
• Additionally, some rootstocks are further resistant to other pests, e.g. Ramsey and Dog Ridge (both champini) are resistant to root-knot nematoads.