Pathway to successful rootstock use: Rootstock Characteristics CREATE A BALANCED VINE Site Factors Final Decision Rootstock Management Vine Balance • Rootstocks influence vine vigour and therefore vine balance. • It is a widely accepted that the best quality wines are produced from balanced vines • The most important selection criteria (apart from phylloxera resistance) is to choose a rootstock that contributes to the production of a balanced vine. Vine Balance • Doing this requires an understanding of the: – inherent vigour of your scion variety and – the potential of your site. • Once you have this information it is possible to do some crude calculations to determine whether it is a high, medium or low vigour rootstock that is required Site Potential • Site potential describes the potential vigour (low, moderate or high) that will be conferred to a vine at a given site • Site potential is a function of: – Soil depth (potential rooting depth) – Soil fertility – Climate Site potential : Potential Rooting Depth of the Soil • In the soil profile the depth to the impenetrable or impermeable layer determines the volume of soil that the vine roots can explore for – moisture and – nutrients • The greater the potential rooting depth, the greater the potential for vigour. Site potential : Soil Fertility • The potential of a site increases with soil fertility. • Clay soils have a greater capacity to store nutrients compared with sand (Gladstones 1992). • Generally soil fertility increases with increasing soil clay content Site potential : Climate • Warm climates encourage growth so long as moisture is not a limiting factor. • Cool to mild climates encourage growth because of the high rainfall that is associated with them. • In general a warm, wet climate has greater potential for vigour compared with a cool, wet climate. • In the absence of irrigation a cool, wet climate has greater potential for vigour than a warm, dry climate Vigour interactions • What happens when site potential, scion vigour and rootstock vigour interact? • Examples taken mostly from commercial vineyards which illustrate these interactions • The first two examples clearly illustrate the importance of matching the rootstock to the scion and site. Vigour interactions Scion Rootstock Site Potential Vigour Vigour Mod-High High High ? Barossa Valley: Thick sand over red mottled clay Shiraz 140 Ruggeri •Excessive Vigour •Semi-premium quality Vigour interactions Site Scion Rootstock Potential Vigour Vigour Low-mod Low-mod Low ? Rheingau: Dry grown, low- mod fertility, soil Riesling 3309C Inadequate Vigour Vigour interactions Site Vigour Scion Rootstock Potential Vigour Vigour Low Low-mod Moderate ? Dry grown, low-mod fertility Riesling 110 Richter Vine Balance Vigour interactions Site Vigour Scion Rootstock Potential Vigour Vigour Moderate Moderate Moderate Coonawarra: Dark clay loam over Cabernet ? rubbly calcrete Sauvignon 5C Teleki Balanced Vine Super premium quality Vigour interactions Site Vigour Scion Rootstock Potential Vigour Vigour Moderate- Low High High ? Shallow loamy sand over red clay Shiraz 1103 Paulsen Balanced Vine Premium quality Vigour interactions Site Scion Rootstock Potential Vigour Vigour Moderate High Low ? Loam over red clay Shiraz 101-14 on weathering rock Balanced Vine - Premium Quality Vigour interactions Site Vigour Scion Rootstock Potential Vigour Vigour Low- Moderate- Low moderate high ? Shallow sandy loam Riesling 5BB Kober over basement rock Balanced Vine- Premium quality Mornington Penn. Vigour interactions Scion Varieties (Chard, Pinot Noir, Cab Sauv., Sauv Blanc) mod., moderate- high and high vigour Site Potential - mod., moderate- high and high vigour? Vigour interactions Site Vigour Scion Rootstock Potential Vigour Vigour Moderate Moderate Moderate Balance Shallow loamy sand over red clay Pinot noir 5C Teleki Pathway to successful rootstock use: Rootstock Characteristics Create a balanced vine SITE FACTORS Final Decision Rootstock Management Site Factors • Rootstocks perform differently at different sites Site influence rootstock performance • Appropriate rootstock selection, requires a thorough understanding of the site Site Factors – Soil properties – Climatic conditions at set/harvest – Water availability – Salt – Presence of soil-borne pests Prioritise, consider and adjust selection Soil Properties It is the soil properties rather than they type which influences rootstock root distribution, rootstock performance and therefore rootstock selection • Soil Texture • Soil Depth • Waterlogging potential • Soil pH • Soil fertility Soil Properties: Texture Soil texture influence on wetting pattern Clay Sand Loam Soil Properties: Texture Rootstock influence on root distribution 30-50cm V. riparia x V. berlandieri V. riparia x V. rupestris V. berlandieri x V. rupestris Figure 1.Hypothetical rootstock root distribution patterns adapted from Guillon (1905) and based on the emergence angles of American Vitis species. Soil Properties: Texture Group A: V. riparia x V. rupestris Sand Loam Clay •Diagram suggests preference for loam and clay-loams •Low proportion of roots in sand •poor WUE in sandy soils, maximum WUE in loams- clay loams • may explain why prone to stress on sandy soils in the heat of summer Soil Properties: Texture Group B: V. riparia x V. berlandieri Sand Loam Clay •Lateral root distribution makes them better suited to clay and clay loam soils (confirmed in literature) •May explain why prone to stress on sandy soils in the heat of summer Soil Properties: Texture Group C. V. berlandieri x V. rupestris Sand Loam Clay •Good proportion of roots in all three wetting patterns •May explain adaptability to wide range of soils Soil Depth • Very important as it determines the volume of soil – Readily Available Water – Nutrient Availability • Greatest influence on site potential vigour (Maschmedt pers comm.) • Deeper the soil, greater the potential site vigour Waterlogging potential • All vines perform poorly in waterlogged soils amend site prior to planting • Rootstocks are generally more susceptible to waterlogging than V. vinifera Less susceptible: Susceptible: •Schwarzmann •99 Richter •SO4 •Ramsey •110 Richter •140 Ruggeri •1103 Paulsen •420A •101-14* *susceptible in early years, but more tolerant as the vine develops. Reference: www.sardi.sa.gov.au/pages/hort/viticulture/rootstock_characteristics.htm Soil Acidity Soils below pH 5.5 generally: • lead to nutrient deficiency (N, P, K, S, Ca and Mg) or • nutrient toxicity in grapevines (Al, Cu and Mn). The following information is based on Whiting (2003) Recommended Rootstocks: Rootstocks to avoid: • 140 Ruggeri • Schwarzmann • 1103 Paulsen • 101-14 • 99 Richter • SO4 • 110 Richter • Ramsey • 5C Teleki • 5BB Kober • 3309C Lime Content • Growers need to be aware that vines grafted to rootstocks are more susceptible to lime-induced chlorosis than ungrafted vines. • Those rootstocks that tolerate the highest levels of active lime are descended from Vitis berlandieri • According to Galet (1998) powdery chalk is most harmful. Lime Content • Most to least lime tolerant according to Galet‟s (1998) rankings: – 140 Ruggeri – 5BB Kober – 420A – 110 Richter – 1103 Paulsen – 99 Richter – SO4 5C Teleki and Ramsey- Not included in Galet‟s rankings, but have been classified in the literature as having lime tolerance Nutrient Elements • N and K are the two most important nutrient elements when selecting and managing rootstocks • Most rootstocks take up and assimilate nitrogen more efficiently than own rooted vines • Some rootstocks are more sensitive to nitrogen than others (Zerihun and Treeby, 2002). Nutrient Elements • Rootstocks influence potassium uptake • High levels of potassium uptake can lead to high juice pH levels, wine instability and poor red wine colour. • Most Australian viticultural soils are abundant in potassium, California the opposite….Chile, N.Z and Argentina? • Rootstock influence on potassium uptake may be an important selection criteria • Rootstocks from Vitis champinii (Ramsey, freedom, harmony, dog ridge, K-stocks) have high potassium uptake and so have lost favour in Oz viticulture Nutrient Elements Rootstocks that Rootstocks that accumulate K at accumulate K at lower moderate levels are: levels are: •420A • Schwarzmann •110 Richter • 140 Ruggeri •5C Teleki • 99 Richter •5BB Kober • 101-14 •1103 Paulsen •SO4 Whiting (2003) Water availability and Drought tolerance Growers need to consider the drought tolerance of a rootstock if they: • Dry grow in arid regions • have soils with low readily available water values (<50mm) • currently have or expect to have seasons where water allocations are restricted • Water source is unreliable from season to season • Limited irrigation system i.e. have areas of the vineyard which suffer from loss of yield and quality as a result of not being able to get around their irrigation shifts in the peak water-use period • Want to maximise their water allocation-increase planted area Water Availability and Drought Tolerance • Results and conclusions obtained from different studies on the water-use efficiency or drought tolerance can be contradictory • Difficult to definitively predict a rootstocks drought tolerance at a given site. • A good rule of thumb is to remember that drought tolerance is related to vine vigour and generally the most vigorous vines have the most extensive root systems and are therefore the most drought tolerant (Soar, 2004). • The classification of rootstocks is based on the consistency of their performances in a number