What are the critical considerations for selecting rootstock when establishing a new vineyard? Flashcards
What are the main roles of rootstocks in viticulture?
Rootstocks provide resistance to soil pests (mainly phylloxera), adapt the vine to specific soil and climate conditions, moderate vine vigor, and influence yield, grape composition, and vineyard longevity.
How can rootstocks affect budbreak and shoot uniformity?
Some rootstocks, especially berlandieri × rupestris types like 1103 Paulsen, can lead to uneven budbreak or missing shoots in varieties like Cabernet Sauvignon.
What is graft incompatibility and how does it appear?
It’s a failure in the graft union over time, showing as weak growth, poor sap flow, excessive suckering, or eventual vine decline.
Why must scion-rootstock interactions be considered on a variety-by-variety basis?
Because rootstocks don’t affect all varieties equally; the same rootstock may increase vigor in one variety and have little effect on another.
How can rootstocks influence virus expression in scions?
Some rootstocks amplify symptoms of viruses. For example, 3309C or Freedom may show stronger fanleaf or leafroll symptoms if the scion is infected.
Why are V. riparia-based rootstocks preferred in clay or waterlogged soils?
They tolerate poor drainage due to their shallow, fibrous roots and natural adaptation to moist environments.
Which rootstocks are recommended for sandy, drought-prone soils?
Deep-rooting, drought-tolerant rootstocks like St. George, Ramsey, 1103 Paulsen, and 140 Ruggeri.
What are the best rootstocks for high-lime (calcareous) soils?
41B, 5BB, and 161-49C—due to their V. berlandieri heritage which provides tolerance to lime-induced chlorosis.
Which rootstocks are salt-tolerant?
1103 Paulsen (very high salt exclusion), followed by 140 Ruggeri, Ramsey, 101-14, and Schwarzmann.
How do rootstocks support drought and heat tolerance?
Through deep root systems and water-conserving physiology, allowing vines to maintain canopy and photosynthesis during dry or hot periods.
What makes a rootstock suitable for cold climates?
It should promote early dormancy and cane maturation to increase winter hardiness. Riparia-based stocks like 3309C are common in cool climates.
What is a short-cycle rootstock and why is it useful in cold areas?
A rootstock that encourages early vine shutdown in autumn, giving the vine time to harden off before winter—critical for survival in cold regions.
What happened with AXR1 rootstock?
It was widely used in California but failed due to its partial V. vinifera parentage, leading to major phylloxera outbreaks and vineyard replantings.
How should rootstocks be selected in nematode-infested soils?
Based on the specific nematode species present; resistant stocks include Ramsey, Freedom, Harmony, and GRN series.
How do rootstocks influence tolerance to soil-borne diseases like Phytophthora or cotton root rot?
Rootstocks with better drainage tolerance (e.g., riparia types) or those observed to survive in infected areas are used for protection.
How do rootstocks vary in vigor potential?
• Low: V. riparia types (e.g., Riparia Gloire, 420A)
• Moderate: V. berlandieri × riparia types (e.g., 5C, 161-49C) • High: V. rupestris, V. champinii types (e.g., 1103P, Ramsey)
How does matching rootstock vigor to the site improve vine balance?
It ensures appropriate canopy size, reduces need for excessive pruning, and avoids over- or under-yielding. Helps with ripening and fruit quality.
What are risks of using a high-vigor rootstock on a fertile site?
Excessive canopy growth, shading, delayed ripening, reduced fruit quality, and increased disease pressure.
How do rootstocks affect grape yield?
By influencing cluster number, berry size, and fruit set. Vigorous rootstocks tend to support higher yields, if balanced.
How do rootstocks impact grape composition?
They affect sugar accumulation rate, acid retention, pH, potassium uptake, and phenolic concentration through their influence on vine physiology.
Why do winemakers consider rootstock when aiming for high-quality wines?
Certain rootstocks can moderate vigor, advance ripening, or reduce berry size—all contributing to better concentration and balance.
How can rootstock choice influence vineyard lifespan?
By resisting pests and adapting to soil/climate, a good rootstock reduces stress, prevents early decline, and maintains productivity over decades.
What are signs of rootstock-related vineyard decline?
Increased vine death after 15–20 years, poor canopy performance, or reduced yields. Can indicate poor disease resistance or root exhaustion.
Why is deep root architecture beneficial for vine longevity?
It allows access to deep water and nutrients, increases drought resilience, and buffers against year-to-year variability.
