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 of studies from both Australia and overseas. Water availability and Drought tolerance Highly Tolerant Moderately Susceptible Ramsey 5BB Kober 1103 Paulsen 5C Teleki SO4 Tolerant Susceptible 140 Ruggeri 101-14 110 Richter Schwarzmann 99 Richter 3309C Riparia Gloire 420A Unfavourable Weather Conditions • Flowering and Ripening – Some rootstocks influence set – Some rootstocks influence rate of ripening Influence on Rate Ripening

• Several rootstocks advance maturity • 101-14 and 5C Teleki have consistently advanced maturity in Australian vineyards compared with ungrafted Vitis vinifera by one week. • In regions prone to inclement weather during the ripening period advancing maturity will: – Lower the risk of late season disease development – Ensure ripeness before the end of the ripening period Influence on Rate Ripening • Delay maturity to: – Spread the harvest load – Avoid ripening during hottest month Influence on Rate Ripening The following rootstocks advance fruit maturity: • 101-14 • 5C Teleki • Schwarzmann • 3309C • 420A The following rootstocks delay fruit maturity: • Ramsey • 140 Ruggeri • 1103 Paulsen • 110 Richter • 99 Richter Influence on Rate Ripening Important to note: • While drought tolerant rootstocks delay maturity, in drought/dry conditions their drought tolerant characteristics keep the canopy fresh and therefore keep ripening ticking over c.f. own roots/other rootstocks. • And vice versa; 101-14 in dry conditions, the canopy will struggle and therefore will not advance maturity compared with own roots. • Its important to think of the „bigger picture‟ Fruit Set • Poor set results from cool, wet and windy conditions during the pre-flowering and flowering period • Merlot and to a lesser extent Chardonnay and Cabernet Sauvignon are susceptible. • Appropriate rootstock selection will : – reduce the incidence of poor fruit set leading to more consistent yields – reduce the proportion of „shot‟ berries potentially leading to better quality (May, 2004). Fruit Set Classification Rootstock References

(Cirami, 1999), (Candolfi- 5C Teleki Vasconcelos, 1995) (Cirami, 1999), (Whiting, 2003, Schwarzmann (Candolfi-Vasconcelos, 1995) (Cirami, 1999), (Dry, unpublished), Improves fruit set and 101-14 (Candolfi-Vasconcelos, 1995) or fertility SO4 (Delas et al., 1991) 3309C (Delas et al., 1991) 420A (Candolfi-Vasconcelos, 1995) Riparia Gloire (Delas et al., 1991) Reduces fruit set/not 1103 Paulsen (Whiting, 2004) recommended for poor set varieties 110 Richter (Candolfi-Vasconcelos, 1995)

The table summarises findings from Australian and overseas research. Australian findings in bold. Salinity

• Soil and water salinity will always be problem in many Australian wine regions because of the naturally high salt levels in the soil • These problems have been exacerbated with the recent drought  reduced water availability means less water to apply as leaching fractions leading to increases in soil salinity • Soil and water salinity effectively reduces water availability to the vine and results in: – Reduced vigour – Reduced yield – Potential reduction in quality Salt Affected Cabernet Sauvignon in Langhorne Creek, S.A. Salinity

• Some rootstocks accumulate salt at low levels • Soil salinity levels above 1.8 dS/m in the root-zone will restrict root growth and performance of own rooted vines. • Where levels exceed this value salt tolerant rootstocks should be used to ensure maximum yield and quality. • need to consider current and future salinity levels Vineyard variability

• All vineyards have variability in vine performance due to differences in soil type and/or topography throughout the block (Bramley, 2005). • Vineyard variability results in: – Inefficiencies in management inputs – Inaccurate/less reliable yield forecasting – Reductions in the consistency of grape quality (Bramley and Hamilton, 2005) Vineyard variability

• Vineyard managers (in Australia) tend to manage variability post-establishment using the principles of precision viticulture.

• Rootstocks, however, offer vineyard managers the opportunity to manage vineyard variability at establishment by matching the potential vigour of a rootstock to the potential vigour of the soil in an attempt to increase vineyard uniformity. Vineyard variability

Growers can do this in two ways: – Match rootstock to soil type and set-up each rootstock as a separate management unit with the aim of uniform management of the vineyard. – Match rootstock to soil type within a block or down a row. 5C Teleki

Site potential increasesSchwarzmann down the hill

101-14

Rootstock 5C Teleki Schwarzmann 101-14

Inherent Rootstock Moderate Low-moderate Low Vigour

Shoot # 15.07a 13.3a 14.07a

PWt (kg/vine) 0.45a 0.33b 0.42ab

Yield (kg/vine) 2.18a 1.23b 1.36b

Values with same letter are not significantly different <0.05. Vineyard variability

Things to consider • Use soil surveys pre-harvest (EM-38 and ground-truthing with soil pits) • Requires an understanding of soil/scion/rootstock interactions • Blocks should still be set up for differential management, with the long-term aim of managing as a single unit • Matching rootstock to soil type down a row is best achieved if there is previous experience of rootstock use on the site Pathway to successful rootstock use: Rootstock Characteristics

Create a balanced vine

Site Factors

FINAL DECISION

Rootstock Management Final Decision

• 1, 2 or 3 rootstocks? • What has performed well in your region/ other similar regions? • What has performed well in the past? • Discuss final selection with fellow growers, winery and nursery • Important decision- take your time • The more information available- better decision Pathway to successful rootstock use: Rootstock Characteristics

Create a balanced vine

Site Factors

Final Decision

ROOTSTOCK MANAGEMENT Rootstock Management

• Different rootstocks perform differently and so need to be managed differently

• Just as it would be inappropriate to manage Shiraz and Chardonnay identically, it is inappropriate to manage two rootstocks in the same manner Key Management Considerations IRRIGATION STRATEGY

NUTRITION STRATEGY Influence of rootstocks on vine water requirements • The influence of rootstock on vine water requirements is related to drought tolerance • Drought tolerant rootstocks have access to greater volumes of soil moisture throughout the growing season Lower irrigation requirements and increased water-use efficiency Therefore as rootstock drought tolerance increases, vine water requirements decrease. Managing to rootstock water requirements 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. Managing to rootstock water requirements Group A (101-14, Schwarzmann, 3309C) • Shallow, low density root system • Consistently classified as drought susceptible • 101-14 + 3309C higher water requirements than other rootstocks and own roots • Schwarzman similar water requirements to own roots, greater than other rootstocks, lower than 3309C and 101-4 Managing to rootstock water requirements Group A (101-14, Schwarzmann, 3309C) • Decrease dripper spacing and apply shorter more frequent irrigations increase amount of water hitting effective root zone  leading to increases in WUE • Will be the first blocks to show water stress  indicator blocks • Pay close attention during heat waves • Management practices to increase moisture retention e.g. Mulching Managing to rootstock water requirements Group B (5BB Kober, 5C Teleki, SO4) • Lateral spreading root system • Classified as moderately susceptible-moderately tolerant • Manage according to soil type/ vigour • Lower water requirements than group A rootstocks • Similar water requirements to own roots • Higher water requirements than C and rootstocks Managing to rootstock water requirements Group B (5BB Kober, 5C Teleki, SO4) • Rapid moisture uptake in spring and prone to leaf loss later in season as soil dries out • Better suited to soils that release moisture more slowly • Save irrigation water for later in the season to avoid basal leaf loss • Decrease dripper spacing and apply shorter more frequent irrigations • Mulching Managing Rootstocks

Group C and D (110R, 99R, 1103 P, 140R, Ramsey) • Consistently classified as drought tolerant • Deep extensive root system Higher RAWs than other rootstocks and own roots • Require less frequent irrigations than ungrafted vines and group A and B rootstocks. Managing to rootstock water requirements Group C and D (110R, 99R, 1103 P, 140R, Ramsey) • Water requirements, in general: 99 Richter > 110 Richter > 1103 Paulsen >140 Ruggeri > Ramsey • Need to make sure that these rootstocks have to work hard for their moisture  If irrigated at same time as other rootstocks, they are kept in luxury conditions Managing drought tolerant rootstocks in „wet‟ years • The production of excessive vigour by drought tolerant rootstocks in „wet‟ seasons can be an issue • overcome this issue is to use a high water use cover-crop • will „dry out‟ the top layers of the soil profile making the vines „work harder‟ resulting in a reduction in shoot vigour • Get control over the water inputs to the vine earlier in the season Managing drought tolerant rootstocks in „wet‟ years • Growers should keep the cover-crop growing for as long is as necessary to achieve the desired outcomes. • In practice cover-crop left in for longer than what would be the case for ungrafted or lower vigour rootstocks. • Penfold (2006) found that chicory and most varieties of ryegrass and fescue are the most effective cover-crop species for reducing water (and nutrient) availability and decreasing vine vigour Nitrogen Requirements

• Nitrogen has a large influence on vine performance and quality • Research has shown that rootstocks differ in their response to nitrogen (Keller et al., 2001a). • Because rootstocks respond differently, they require different management strategies Nitrogen Requirements

• Difficult to provide any strong management advice for individual rootstocks: – positive linear relationship between % N at flowering and pruning weights (vigour) N supply can be used as management option for controlling vine vigour  High vigour rootstocks generally require lower inputs ad vice versa – Rootstock should be sampled separately Rootstocks and Vigour

Moderate – High Vigour Rootstocks

Reduce water and nitrogen inputs

Lower Vigour SUMMARY: • Arm yourself with knowledge • Identify whether it is a low, moderate or high vigour rootstock that will contribute to vine balance • Identify the site factors that will influence rootstock performance  adjust selection • Confirm selection(s) based on past or other experience • Manage different rootstocks differently • Further Reading: • May, P. (1994) Using Grapevine Rootstocks: The Australian Perspective. (Winetitles: Adelaide). • Wolpert, J.A., Walker, M.A. and Weber, E. (1992) Rootstock Seminar: A Worldwide Perspective. (American Society for Enology and Viticulture: Davis). • Whiting, J (2004). Rootstocks. In Viticulture Volume 1: Resources. Eds. Dry, P.R. and Coombe, B.G. (Winetitles: Adelaide). • Whiting, J. (2003) Selection of Grapevine Rootstocks and Clones for Greater Victoria. (Department of Primary Industries: Victoria). • References: • Bramley, R. G. and Hamilton, R.P. (2005) Hitting the zone: making viticulture more precise. In Proc. 12th Aust. Wine Ind. Tech. Conf., 2004. Eds. Blair, R., Williams, P. and Pretorius, S. (AWITC), pp 57-61. • Carbonneau, A. (1985). The early selection of grapevine resistant rootstocks for resistance to drought conditions. American Journal of Enology and Viticulture 36, 195-198. • Cirami, Furkliev, J. and Radford, R. (1994) Summer drought and vine rootstocks. Australian and New Zealand Grape grower and Winemaker No. 366a, 145. • Condolfi-Vasconcelos, M.C. (1995) Phylloxera resistant rootstocks for grapevines. North West Berry and Grape Information Network. • Cirami, R. (1999) Guide to the selection of phylloxera resistant rootstock. (Phylloxera and Grape Industry Board of South Australia). • Delas, J.J. et al (1991) in Delas, J.J. (1992) Criteria used for rootstock selection in France. In Proc. Rootstock Seminar: A worldwide perspective, Reno, 1992. Eds. J.A. Wolpert, M.A. Walker et al. (American Society for Enology and Viticulture), pp 1-14. • Dry, P.R., Maschmedt, D.J., Anderson, C.J., Riley, E., Bell, S-J. and Goodchild, W.S. (2004) The grapegrowing regions of Australia. In Viticulture Volume 1: Resources. (Winetitles: Adelaide). • Dry, P.R., Iland, P.G. and Ristic, R. (2005) What is vine balance? In Proc. 12th Aust. Wine Ind. Tech. Conf., 2004. Eds. Blair, R., Williams, P. and Pretorius, S. (AWITC), pp 68-74. • Ezzahouani, A. and Williams, L. (1995). The influence of rootstock on leaf water potential, yield, and berry composition of ruby seedless grapevines. The American Journal of Enology and Viticulture. 46: 559-563. • Galet, P. (1998) Grape Varieties and Rootstock Varieties. (Oenoplurimédia), France • Gibberd, M., Walker, R., Blackmore, D. and Congdon, A. (2001) Transpiration efficiency and carbon isotope discrimination of grapevines grown under well watered conditions in either glass house or vineyard. Australian Journal of Grape and Wine Research. 7, 110-117. • Guillon, J. M. (1905) Étude générale de la vigne: Historique les vignobles et les crus anatomie et physiologie, sol et climat. Masson, Paris. • Gladstones, J. (1992) Viticulture and Environment. (Winetitles: Adelaide). • Keller, M., Kummer, M. and Carmo-Vasconcelos, M. (2001a) Soil nitrogen utilisation for growth and gas exchange by grapevines in response to nitrogen supply and rootstock. Australian Journal of Grape and Wine Research 7, 2-11. • Krstic, M. and Hannah, R. (2003) Matching Scion and Rootstock combinations in Sunraysia. Final Report to GWRDC. Project No. RT02/19-3 (Dept. Primary Industries: Mildura). • May, P. (2004) Flowering and fruitset in grapevines. (Lythrum Press: Adelaide). • McArthy, M., Cirami, R., Furkaliev, J. (1997) Rootstock response to Shiraz to dry and drip irrigated conditions. Australian Journal of Grape and Wine Research. 3, 95-98. • Nicol, J.M., Stirling, G.R., Rose, B.J., May, P. and Van Heeswijk, R.V. (1999) Impact of Nematodes on grapevine growth and productivity: Current knowledge and future directions, with special reference to Australian viticulture. Australian Journal of Grape and Wine Research 5, 109-127. • Pech, J., Stevens, R.M. and Gibberd, M.R. (2001) Responses of Chardonnay and Shiraz on five rootstocks to reduced irrigation. Poster Summary. Proceedings of the Australian Wine Industry Technical Conference. • PIRSA Land Information (2000) Assessing Agricultural Land. [CD ROM]. Primary Industries and Resources South Australia. • Quader, M., Riley, I. and Walker, G. (2002) Nematode parasites in South Australian vineyards. The Australian and New Zealand Grape grower and Winemaker. No. 464, 62-64. • Smart, D.R., Schwass, E., Lakso, A. and Morano, L. (2006) Grapevine rooting patterns: a comprehensive review American Journal of Enology and Viticulture. 57 (1), 89-101. • Soar, C.J., Dry, P. R. and Loveys, B. R. (2006) Scion photosynthesis and leaf gas exchange in Vitis vinifera L. Cv. Shiraz: Mediation of rootstock effects via xylem sap ABA. Australian Journal of Grape and Wine Research. 12, 82-96. • Southey, J.M. (1992) Grapevine rootstock performance under diverse conditions in South Africa. In Proc. Rootstock Seminar: A worldwide perspective, Reno, 1992. Eds. J.A. Wolpert, M.A. Walker et al. (American Society for Enology and Viticulture), pp 27-37. • Stirling, G.R., Stanton, J.M. and Marshall, J. (1992) The importance of plant-parasitic nematodes to Australian and New Zealand agriculture. Australasian Plant Pathology 24, 104-115. • Swanpoel, J.J. and Southey, J. M. (1989) The influence of rootstock on the rooting pattern of the grapevine. South African journal of Enology and Viticulture 10 (1), 23-27. • Tee, E. and Burrows, D. (2004) Best irrigation management practices for viticulture in the Murray Darling Basin. (Cooperative Research Centre for Viticulture: Glen Osmond). • Virgona, J.M., Smith, J., Holzapfel, B. (2003) Scions influence apparent transpiration efficiency of Vitis Vinifera (cv. Shiraz) rather than rootstocks. Australian Journal of Grape and Wine Research 9, 183-185. • Walker, R. and Stevens, R. (2004). Recent developments in the understanding of the effects of salinity on grapevines. Unpublished. • Walker, R., Blackmore, D., Clingeleffer, Godden, P., Francis, L. Valente, P. and Robinson, E. (2002) The effects of salinity on vines and wines. Australian Viticulture 6 (4), 11-21. • Walker, R.R. et al. (1998) “Effects of the rootstock Ramsey (Vitis champini) on ion and organic acid composition of grapes and wine, and on wine spectral characteristics.” Australian Journal of Grape and Wine Research 4, 100-110. • Walker, R.R., Read, P.E. and Blackmore, D.H. (2000) Rootstock and salinity effects on rates of berry maturation, ion accumulation and colour development in Shiraz grapes. Australian Journal of Grape and Wine Research 6, 227-239. • Walker, R. (2004). Application of carbon isotope discrimination technology to understanding and managing wine grape water use efficiency. CRCV Final Report to GWRDC. Project Number CRCV 99/10. • Whiting, J. and Orr, K. (1990) 99 Richter and 101-14 rootstocks susceptible to waterlogging. The Australian Grapegrower & Winemaker No. 321, 60. • Whiting, J. (2003) Selection of Grapevine Rootstocks and Clones for Greater Victoria. (Department of Primary Industries: Victoria). • Zhang, X., Walker, R.R., Stevens, R.R., and Prior, L.D. (2002) Yield-salinity relationships of different grapevines (Vitis Vinifera L.) scion-rootstock combinations. Australian Journal of Grape and Wine Research 8, 150-156.