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Phylloxera-resistant Rootstocks for Grapevines

Additional Fact Sheets on Phylloxera:

Contributing List of Authors: Ed Hellman. Oregon State University. This fact sheet and others on grape phylloxera were produced as a set by a phylloxera task force at Oregon State University: Bernadine Strik, Extension Berry Crops Specialist; M. Carmo Candolfi-Vasconcelos, Extension Viticulture Specialist; Glenn Fisher, Extension Entomologist; Edward Hellman, Extension Horticulture Agent; Steven Price, Post-doctoral Research Associate, viticulture; Anne Connelly, Master’s student, horticulture; and Paula Stonerod, Research Aide, horticulture. The authors of this fact sheet acknowledge the help and guidance of others on this task force.

History

The practice of grafting, which combines two different varieties or species to form a new plant with a blend of characteristics, is a technique known from ancient times both in fruit trees and viticulture. It has been used historically to change variety, enhance vigor, or increase limestone tolerance.

Grafting became a common practice in viticulture after the phylloxera epidemic (see Phylloxera: What is it?). Phylloxera was introduced in Europe (1862) through the importation of rooted vines from North America. The pest lead to the complete destruction of the vineyards in southern France at the end of the nineteenth century. Phylloxera spread at a rate of approximately of 12.5 miles a year (or faster with the help of man) and within 20 years, phylloxera had killed virtually every vine in France. Laliman was the first to suggest biological pest control of phylloxera: grafting the susceptible wine varieties to the resistant American species.

The rapid adoption of this practice lead to a chaotic period (1880-1930) when nurseries offered a confusing and disorderly assortment of rootstocks. The use of inappropriate rootstocks caused new problems that were not known previously, particularly lime-induced chlorosis. Extensive research on rootstocks, particularly after 1950, revealed that several aspects of scion behavior such as adaptation to growing conditions, susceptibility to mineral deficiencies or toxicities, tolerance to soilborne pests and diseases, vigor, productivity, fruit quality, etc. were dependent on features of the rootstock. After more than a century of experimentation with rootstocks in Europe and in the New World, there is a considerable amount of information that can be drawn upon. Still, the choice of a rootstock for a particular location depends on the complex interactions between soil type, depth, physical and chemical properties, pests, diseases, water availability, and environmental factors, thus on-site evaluation is imperative.

Choice of the Appropriate Rootstock:

The first criterion in choosing a rootstock is its resistance to grape phylloxera. Resistance to nematodes is also important in infested soils, but a nematode-resistant rootstock with questionable phylloxera resistance is not a wise choice. Exceptions to the rule are very light siliceous or sandy soils, provided that the sum of silt + clay + humus in the soil does not exceed 5%. In these soils, vines do not seem to be affected by phylloxera and can be grown own-rooted (not grafted) or grafted to nematode-resistant rootstocks such as Harmony, Freedom, Ramsey, Dog Ridge, or 1613 C. The clay content should not exceed 3%. Grafting to phylloxera-resistant rootstocks becomes imperative if the clay content exceeds 7%.

Rootstocks with Vitis vinifera parentage should not be used because of insufficient phylloxera resistance. The use of some rootstocks recommended in Europe for limestone tolerance, such as 41B, 333 EM, and Fercal (crosses of V. berlandieri and V. vinifera), is not imperative in Oregon, since most of our vineyard soils are slightly acid.

The reason rootstocks susceptible to phylloxera are still being planted is usually the ease of propagation, which makes them attractive to the nursery industry, furthering their availability in the market. There is presently a vast choice of phylloxera-resistant rootstocks with a wide range of adaptability to different soil and climatic conditions. The parentage of rootstocks currently being offered by nurseries is illustrated in Figure 1.

Other viticultural attributes of rootstocks, such as drought and lime tolerance, are secondary factors which aid in the selection of a stock to suit a particular soil type or vineyard condition.

To obtain the best fruit quality, avoid excessive vine vigor. The best wines of the world are produced on low- to moderate-vigor vineyards. It is very important to adapt the rootstock choice to the soil and climate to optimize vine size. Do not use vigorous rootstocks in fertile soils. High-vigor rootstocks can be of great value under very dry conditions, in non-irrigated vineyards. Trellising systems with divided canopies and wide-spaced vines require more vigorous rootstocks than single-curtain, close-spacing systems.

Root density (root mass per unit soil volume) is predominantly a function of rootstock cultivar. Spatial root distribution is a function of the soil environment. Rootstocks that avoid water stress by developing a deep root system should not be used in soils that are shallow or where soil layering prevents deep rooting.

Mineral deficiencies are sometimes aggravated by less favorable scion-rootstock combinations. In soils with a poor supply of magnesium, varieties with high magnesium demand (such as Chasselas, Cabernet Sauvignon, Merlot, Cardinal, Gewurtztraminer, Ugni blanc, Sauvignon blanc, Syrah) should not be grafted onto rootstocks susceptible to magnesium deficiency. Similarly, if the levels of potassium in the soil are low, varieties with high potassium demand (such as Cabernet Sauvignon, Merlot, Aramon, Cinsaut, Syrah, Muller-Thurgau) should not be grafted to rootstocks prone to potassium deficiency.

Rootstock resistance to nematodes is not broad-spectrum, but depends on the nematode species. The information reported here refers to root knot, dagger, and root lesion nematodes, which are the most common nematode pests in foreign viticultural regions. In Oregon, ongoing studies are showing that the most common species seem to be the ring nematode (Criconemella spp.) and the dagger nematode (Xiphinema spp.). There is no information available on rootstock cultivar resistance to ring nematode and we hope to fill this gap in the near future.

Characteristics of Commonly Grafted Phylloxera-resistant Rootstocks:

Riparia Gloire de Montpelier

  • Vigor: Low to moderate.
  • Effect on fruit set: Improves flowering and berry set. Varieties grafted to this have often declined through a tendency to overbear.
  • Effect on maturity: Advances maturity.
  • Soils: Shallow-growing, well branched root system. Only suited to deep, moist, and fertile soils with good drainage. Should not be used in poor, sandy soils. Not appropriate for calcareous soils and dry sites.
  • Pests and diseases: Very high resistance to phylloxera.
  • Propagation: Roots and grafts easily. Good graft compatibility with V. vinifera.
  • Other comments: In poor growing conditions, vines grafted on Riparia give stems that remain thinner than the scion grafted on it. Therefore, it is not appropriate for low density plantings with considerable fruit weight per vine. It is still considered one of the best rootstocks for quality wine grape production.

Rupestris Saint George

  • Vigor: Very vigorous.
  • Effect on fruit set: Due to extreme vigor, it induces coulure (poor fruit set) and, therefore, is not suitable for varieties with irregular set.
  • Effect on maturity: Has a long vegetative cycle and delays the maturity of the scion.
  • Soils: Needs a deep soil and a penetrable subsoil. Under such conditions, it can resist drought even if the soil is poor. In shallow, dry soil, it will suffer from drought sooner than Riparia. On no account should it be planted where there is stagnant water in the subsoil during the growing season.
  • Pests and diseases: High resistance to phylloxera. Very sensitive to rootknot, sensitive to dagger, and moderately resistant to root lesion nematodes. Very susceptible to the root-rotting fungi Dematophora nectarix Hartig and Agricus melleus and very sensitive to fanleaf degeneration.
  • Propagation: Roots easily and grafts well and has excellent affinity with V. vinifera.
  • Other comments: Has a tendency to produce shoots from bellow the graft. In the nematode-infested, deep, irrigated, sandy soils of the coastal plains of southern France, Rupestris St George is being replaced by SO4, which performs much better under these conditions.

Riparia x Rupestris Crosses

Based on the excellent cultural characteristics of these two species, it was expected that the crosses would lead to high quality rootstocks. In fact, following their hybridization, these rootstocks expanded rapidly in every viticultural country and were highly praised in the beginning. They are still regarded as rootstocks for quality winegrape production. In France, however, their use is decreasing in favor of Berlandieri x Riparia crosses, which have a superior adaptation spectrum.

3309 Coudrec

  • Vigor: Low to moderate.
  • Effect on fruit set: It is a stock recommended for varieties with poor set but the high fruitfulness it induces requires crop removal in young vines.
  • Effect on maturity: Advances the maturity of the scion.
  • Soils: Has a deep-growing, well branched root system. It is a good rootstock for deep, well-drained cool soils that are well supplied with water. It is unsuited for dry and shallow conditions and is not appropriate for heavy soils. Has a moderate resistance to lime-induced chlorosis. Does not tolerate saline soils well. Has a tendency to induce potassium deficiency in overcropped young vines on clay soils. Experience from California shows that young vines grafted onto 3309 are very nutrient demanding.
  • Pests and diseases: High resistance to phylloxera. In France, it is reported to be sensitive to any species of rootknot nematodes and in California is regarded as susceptible to nematodes. However, in Australia, it is considered resistant to dagger and root lesion nematodes. Experiments in South Africa showed that 3309 C is resistant to crown gall but susceptible to phytophthora. It has recently acquired a bad reputation in California for its sensitivity to viruses when grafted to field selections of scion wood.
  • Propagation: Easy to graft and root.
  • Other comments: In Burgundy, it is being replaced by SO4. Experience in California and Australia suggests that other rootstocks are usually better.

101-14 Millardet et de Grasset

  • Vigor: Low to moderate.
  • Effect on fruit set: Improves fruit set (better than 3309 C in Switzerland).
  • Effect on maturity: Advances maturity (shorter cycle than 3309 C).
  • Soils: It has a fairly shallow, well branched root system and requires moist, deep soils. Is a good rootstock for fresh clay soils even if they are poorly drained. Not appropriate for dry and well-drained positions on slopes. It has a moderate resistance to lime-induced chlorosis. It should not be used in acid soils without prior pH adjustment with lime application. It is resistant to salinity.
  • Pests and diseases: Has high resistance to phylloxera. Is moderately resistant to nematodes. In South Africa, it is reported to be resistant to crown gall and moderately resistant to phytophthora.
  • Propagation: Easy to graft and root. In South Africa it shows lack of compatibility with some varieties such as Syrah and Chardonnay.
  • Other comments: In Switzerland, it produced slightly higher yields with the same sugar content compared to 3309 C.

Schwarzmann

  • Vigor: Moderate (more vigorous than 3309 and 101-14).
  • Effect on fruit set: Improves the fertility of the scion.
  • Soils: In Australia, it does best on moist, deep soils and should not be used where summer drought is common. According to Galet (France), this is a good stock for dry, non-chlorotic soils. In New Zealand it is not recommended for excessively heavy soils.
  • Pests and diseases: High resistance to phylloxera. Highly resistant to rootknot and dagger nematodes.
  • Propagation: Easy to graft and root.
  • Other comments: The advantage of this rootstock compared to Riparia Gloire and the other Riparia x Rupestris hybrids is that it is more tolerant to calcareous soils and its trunk thickens as rapidly as that of the scion grafted on it. This rootstock of uncertain origin is probably a descendent of the 101 series from Millardet. It is not well documented in the literature.

Berlandieri x Riparia Crosses

This group is characterized by good phylloxera resistance, resistance to lime in the soil, and good affinity with V. vinifera. They typically confer low to moderate vigor to the scion and some of them are drought tolerant. They are suited to cool climate, quality wine growing areas due to earliness of maturity and moderate vigor. They are probably the best suited group for Oregon conditions.

161-49 Coudrec

  • Vigor: Low to moderate.
  • Soils: The root system is shallow-growing and well branched. It has a high resistance to lime-induced chlorosis, but it does not tolerate salt or drought.
  • Pests and diseases: Its main defect is susceptibility to thyllosis, a physiological disorder that induces a sudden wilting of the leaves in dry regions. Susceptible to nematodes.
  • Propagation: Numerous cases of incompatibility with V. vinifera have been reported. Roots moderately but the results of bench grafting are sometimes capricious.
  • Other comments: Not available in the U.S.

SO4

  • Vigor: Moderate to vigorous.
  • Effect on fruit set: The information available is conflicting. Germany, South Africa, and New Zealand report it to be especially suited for varieties with poor set. In France, its excessive vigor is reported to cause poor fruit set.
  • Effect on maturity: Advances the maturity of the scion according to researchers in Germany, South Africa, and New Zealand and delays maturity according to French literature.
  • Soils: Has a shallow-growing root system. Tolerates high levels of lime in the soil and performs satisfactorily in acid soils. This stock is well adapted to a wide range of soils, but does best in light, well drained soils of low fertility. It is suited to humid soils, but it is not recommended for dry conditions. In New Zealand, it is reported to be drought tolerant. It assimilates magnesium poorly and when grafted with Merlot or Cabernet Sauvignon, it induces inflorescence necrosis.
  • Pests and diseases: Very high phylloxera resistance and is resistant to rootknot nematodes. In France, it favors the development of botrytis infestation in the fall due to excessive vigor. Varieties with high magnesium demand should not be grafted onto SO4 because they tend to show magnesium deficiency and inflorescence necrosis symptoms. It is susceptible to thyllosis.
  • Propagation: Roots well but results of bench grafting are sometimes disappointing.
  • Other comments: This stock develops slowly and shows low vigor in the first years of development. Vine vigor decreases drastically after 15-20 years, leading to the need for vineyard re-establishment. 5C was mistaken for SO4 in California for many years.

Teleki 8 B

  • Vigor: Moderate.
  • Effect on fruit set: Very fruitful in good soils but not appropriate for high-yielding varieties.
  • Soils: Its root system is shallow-growing. Not appropriate for shallow dry soils. Very resistant to lime-induced chlorosis. It is more drought tolerant than 5BB.
  • Pests and diseases: Has high phylloxera resistance and is resistant to rootknot nematodes.
  • Propagation: Roots poorly but grafts well.
  • Other comments: This stock was originally a mixture of five plants and was further selected in Germany (Durlach 50, 51, 52), Italy (Ferrari, Cosmo 2, and Cosmo 10), and Romania (Dragasani 37, 57).

5BB Kober

  • Vigor: Vigorous.
  • Effect on fruit set: Can cause imperfect set in vigorous varieties and fertile soils.
  • Effect on maturity: Has a relatively short season. In vigorous, valley floor sites, the excess of vigor can affect fruit set and delay maturity.
  • Soils: Root system is shallow-growing. Tolerates high levels of lime in the soil. It is one of the best stocks for humid, compact, calcareous soils. Less appropriate for sites with prolonged drought. Has no tolerance of salt. Not suitable for high-yielding varieties due to poor potassium uptake.
  • Pests and diseases: Has very good resistance to phylloxera and moderate resistance to rootknot and dagger nematodes. In California, it is reported to be sensitive to phytophthora and, thus, is not recommended for sites prone to standing water. Susceptible to thyllosis.
  • Propagation: Roots and grafts well. Some incompatibility with table grape varieties were reported in Italy and with wine varieties (Cabernet franc, Colombard, Servant, Abouriou) in France.
  • Other comments: This stock is not suited for regions affected by severe winter frosts because its roots do not tolerate temperatures below -8oC (18oF) at 30 cm depth (12 in.).

5 C Teleki

  • Vigor: Moderate (between 5BB and SO4).
  • Effect on fruit set: Well suited for varieties with poor set.
  • Effect on maturity: Advances maturity. It is the earliest maturing rootstock of this group.
  • Soils: Suitable to well-drained, fertile soils. It is a good choice for heavy soils (clays and clay loams). Has moderate drought resistance and high tolerance to calcareous soils.
  • Pests and diseases: Very good resistance to phylloxera and good resistance to rootknot and dagger nematodes.
  • Propagation: Roots and grafts well.
  • Other comments: Was selected in Austria from Teleki 5A. In California, it was erroneously sold as SO4. This rootstock has many of the attributes of 5BB except that it tends to advance ripening. It, therefore, has special value for very cool climates.

Kober 125 AA

  • Vigor: Very vigorous.
  • Effect on fruit set: Not appropriate for varieties with irregular set.
  • Soils: High phylloxera resistance. Moderately resistant to lime-induced chlorosis. Greater drought tolerance than 5BB. In Germany, it is recommended for a very wide range of soils, particularly heavy, compact soils with poor aeration and drainage. This stock is not appropriate for shallow soils. In New Zealand, it is recommended for poor stony soils.
  • Pests and diseases: High phylloxera resistance.
  • Propagation: Roots well but has slow development initially.
  • Other comments: In most aspects, this rootstock is similar to 5BB, though it is more vigorous in growth and is recommended for special conditions only. It gives good results with White Riesling, Muller-Thurgau, Sylvaner, Chasselas, and the Pinot family. It is best suited to high-yielding varieties, such as Muller-Thurgau.

420 A Millardet et de Grasset

  • Vigor: Low to moderate.
  • Effect on fruit set: Improves scion fertility.
  • Effect on maturity: Has a long vegetative cycle.
  • Soils: Has a fairly shallow-growing and well branched root system. Is well suited to poorer, heavy-textured soils. Is a good stock for dry hillside sites according to Italian and Australian sources, but susceptible to drought according to French and South African sources. Does not withstand waterlogging. Has good resistance to lime-induced chlorosis but is prone to potassium deficiency.
  • Pests and diseases: High phylloxera resistance. Moderate resistance to rootknot nematodes and susceptible to dagger and root lesion nematodes. Susceptible to phytophthora.
  • Propagation: Does not root and graft easily. Has poor affinity with Sangiovese in Italy.
  • Other comments: The oldest commercialized Berlandieri x Riparia hybrid and is used mainly for early-ripening table grapes and high quality winegrapes. Grows very slowly and has a tendency to overcrop in early years of vine development.

Berlandieri x Rupestris Crosses

The rootstocks belonging to this group are vigorous, often very resistant to drought, and are the best adapted to warm regions. They have high phylloxera resistance and tolerate calcareous soils. The vegetative cycle is usually longer than the Berlandieri x Riparia and Riparia x Rupestris crosses and, therefore, they are less adequate for cool climate regions. However, their adaptability to poor growing conditions, infertile soils, and drought are among the characteristics that make this group worth trying in Oregon.

99 Richter

  • Vigor: Very vigorous.
  • Effect on fruit set: Has a much shorter vegetative cycle than Rupestris St. George, which means that it could be grown under cool conditions.
  • Effect on maturity: Delays scion maturity.
  • Soils: The root system is very strongly developed and very deep-growing. Well suited to a wide range of soils, but wet, poorly drained situations should be avoided. This stock is drought tolerant and performs well in acid soils. It does not tolerate salt but tolerates high levels of lime in the soil. Assimilation of magnesium is poor.
  • Pests and diseases: High resistance to phylloxera and rootknot nematodes and moderate resistance to dagger and lesion nematodes.
  • Propagation: According to South African experience, it roots and grafts extremely well, but the French report less successful results with bench grafting.
  • Other comments: This was the outstanding rootstock in a long-term rootstock trial in Victoria, Australia. In France, under dry conditions, its performance is usually inferior to 110 R. In South Africa, it is considered the best rootstock for deep, fertile soils under irrigation.

110 Richter

  • Vigor: Moderate to vigorous.
  • Effect on fruit set: Not appropriate for varieties with irregular set.
  • Effect on maturity: Has a very long vegetative cycle and delays maturity.
  • Soils: The root system of 110 R is not as deep-growing as that of 99R or Rupestris St. George. It is well suited to all kinds of soils, including acid soils. This is an excellent rootstock in warm grapegrowing areas with an arid climate. Its resistance to drought is superior to 99R and it does well on badly-drained shallow clays. This is a good rootstock for slopes or dry-farmed sites. It assimilates magnesium and potassium poorly but tolerates lime in the soil.
  • Pests and diseases: Highly resistant to phylloxera. Moderate resistance to rootknot nematodes.
  • Propagation: Roots and grafts well.
  • Other comments: This is one of the most important rootstocks in Portugal, Spain, Greece, North Africa, and Israel and ranks third in plantings in France. The initial vine growth is slow because it first develops the root system.

1103 Paulsen

  • Vigor: Moderate to vigorous.
  • Effect on maturity: Has a long vegetative cycle, thus delaying maturity of the scion.
  • Soils: The root system is deep-growing, strongly developed, resembling that of Rupestris St. George. It is reported to be more drought tolerant than 110 R and 140 Ru in Sicily and Algeria. In calcareous soils in France, it performs better than 99 R but not as good as 110 R, 161-49 C, SO4, and 420 A. It does well in acid soils. It is moderately tolerant of salt, but assimilates potassium poorly.
  • Pests and diseases: Has high resistance to phylloxera, good resistance to rootknot nematodes, and moderate resistance to dagger nematodes.
  • Propagation: Roots and grafts well and has good affinity with V. vinifera.
  • Other comments: This rootstock was bred and selected in Sicily and is used in Italy, southern France, and North Africa.

140 Ruggeri

  • Vigor: Very vigorous.
  • Effect on fruit set: In fertile soils, it causes poor fruit set due to excessive vigor.
  • Effect on maturity: Has a very long vegetative season delaying maturity.
  • Soils: The root system is very deep-growing, well branched, resembling that of Rupestris St. George. Because of its extreme vigor, it is not recommended as a rootstock for deep, fertile soils, well supplied with water. Performs well in shallow, dry, calcareous soils and is very drought tolerant, well adapted to acid soils, and resistant to salinity. In the group Berlandieri x Rupestris, it is the most resistant to lime in the soil. Assimilates potassium poorly.
  • Pests and diseases: Highly resistant to phylloxera. Moderate resistance to rootknot nematodes.
  • Propagation: Grafts well but is not easy to root.
  • Other comments: This is a Sicilian rootstock, very popular in Italy and North Africa. It is considered the best rootstock for arid, calcareous soils.

Riparia x Solonis Crosses

1616 Coudrec

  • Vigor: Moderate.
  • Effect on fruit set: Improves scion fertility.
  • Effect on maturity: Advances the maturity of the scion.
  • Soils: Has a shallow growing, well-branched root system. This stock is sensitive to drought and it is best adapted to fertile, humid, badly-drained soils, provided they do not contain much lime. Grows poorly in infertile and light sandy soils. Has high tolerance to salt and, in France, is mostly used on saline soils along the Mediterranean Coast.
  • Pests and diseases: Good resistance to phylloxera and high resistance to rootknot nematodes.
  • Propagation: Roots well but the results of bench grafting are poor.
  • Other comments: The main advantages of this rootstock are the nematode and salt resistance.

Complex Crosses

Riparia x Cordifolia x Rupestris

44-53 Malègue

  • Vigor: Moderate.
  • Effect on fruit set: Improves fruit set of the scion.
  • Effect on maturity: Advances maturity.
  • Soils: Has a deep-growing very strongly developed root system and performs well under drought conditions. Moderate resistance to lime-induced chlorosis and often suffers from magnesium deficiency. Used in the acid soils of the Eastern Pyrenees and may be a good stock for dry regions as long as the soil has a low lime content.
  • Pests and diseases: Very high resistance to phylloxera. Resistant to nematodes and has been reported to be resistant to fan leaf virus.
  • Propagation: Roots and grafts extremely well.
  • Other comments: Qualities are similar to the stock 3309 C.

Riparia x Berlandieri x Rupestris

Gravesac

  • Vigor: Moderate.
  • Soils: Suited for well drained soils of low fertility. Tolerates acid soils and is resistant to lime-induced chlorosis.
  • Pests and diseases: Has a high phylloxera resistance.
  • Propagation: Roots and grafts well and has good affinity with the varieties tested so far.
  • Other comments: This is a new rootstock, bred in Bordeaux specifically for tolerance to acid soils (cross of 161-49 C x 3309 C) but it is still being tested. In Bordeaux, it performs like SO4. It is not available in the U.S. but it would be interesting to test in Oregon.

Further Reading:

Ahmedullah, M. and D. G. Himelrick. 1989. Grape management. In: G. J. Galletta and D. G. Himelrick (eds.). Small fruit crop management. Prentice Hall, NJ. pp. 383-471.

Carbonneau, A. 1985. The early selection of grapevine rootstocks for resistance to drought conditions. Amer. J. Vitic. Enol. 36:195-198.

Castéran, P. 1971. Etablissement du vignoble. In: Sciences et Techniques de la Vigne, II. J. Riberau-Gayon and E. Peynaud (eds.). Dunod Paris. pp. 35-99.

Chauvet, M. and A. Reynier. 1979. Manuel de viticulture. Éditions J.B. Baillière.

Dalmasso, G. and I. Eynard. 1979. Viticoltura Moderna – Manuale Pratico. Ottava Edizione. Ulrico Hoepli, Milano.

Foulonneau, C. 1971. Guide de la plantation des vignes. Institut Technique de la Vigne et du Vin. Paris. 196 pp.

Galet, P. 1988. Cépages et vignobles de France, Tome I: Les vignes américaines. 2nd edition. Déhan, Montpellier. 553 pp.

Galet, P. 1991. Précis d’Ampélographie Pratique. 6th edition. Déhan, Montpellier. 258 pp.

Hardie, W. J. and R. M. Cirami. 1988. Grapevine rootstocks. In: Viticulture – Vol. 1: Resources. B. G. Coombe and P. R. Dry (eds.). Winetitles, Adelaide. pp. 154-176.

Hillebrand, W., H. Lott, and F. Pfaff. 1993. Taschenbuch der Rebsorten. 10th edition. Fachverlag Dr. Fraund GmbH. Mainz. 462 pp.

Howell, G. S. 1987. Vitis rootstocks. In: Rootstocks for Fruit Crops. R. C. Rom and R. B. Carlson (eds.). John Wiley & Sons, Inc. pp. 451-472.

Jackson D. and D. Schuster. 1994. Grapes and Wine in Cool Climates. Gypsum Press, New Zealand.

Pongrácz, D. P. 1983. Rootstocks for grapevines. David Philip. Cape Town. 150 pp.

Simon, J. L. 1992. W. Eggenberger, W. Koblet, M. Mischler, J. Schwarzenbach. Viticulture. 3rd ed. Editions Payot, Lausanne. La Maison Rustique, Paris.

Wolpert, J. A., M. A. Walker, E. Weber, L. Bettiga, R. Smith, and P. Verdegall. 1994. Use of phylloxera-resistant rootstocks in California: Past, present and future. Grapegrower 26:10-17.

Wolpert, J. A., M. A. Walker, and E. Weber. 1992. Rootstock seminar: A worldwide perspective. Reno, NV, 24 June 1992. pp. 1-14.