The outstanding performance of GRAD® 44-53 rootstock since GRAD® introduced it to New Zealand, proves it is a highly reliable, moderate-vigour, robust, and strongly drought resistant cool-climate-adapted rootstock.

GRAD® 44-53 rootstock in brief:

  • Unique GRAD® clonal re-selection of low-moderate vigour (e.g.,  comparable to C 3309) but with very high robustness
  • Highly drought resistant, but (as with the similarly, but quite independently, hybridised Malegue 106-8) both its Vitis cordifolia and Vitis riparia bloodlines also carry though in its being highly adapted to cool climate conditions
  • Consistently tested free of detectable virus by PCR test. All 30 first-generation mothervines (now at Stanmore Farm nursery) made from the foundation clones have proven free of GLRaV1,2,3, and GVA by multiple E.L.I.S.A. tests
  • Vines grafted GRAD® 44-53 are performing extremely well in vineyards in Hawkes Bay, Marlborough, and North Canterbury, particularly in poor deep stony soils and dry conditions
  • Has a strongly developed branching and plunging root system that is far more deeply-growing than that of V. riparia or the hybrids of V. riparia x V. rupestris, and thus exploits far more subsoil depth than the rootstocks which are by far most commonly used in New Zealand
  • Because of its genetically-programmed deep rooting habit, an excellent stock for use in organic vineyards where minimal or no under-vine tillage or weed control is practised once vines are established
  • Advances scion ripening — 3 days earlier than V. riparia in Oregon trials — and enhances scion fertility
  • In well managed high-production conditions at ca. 2,000 to 2,500 vines / ha., will produce robust vines capable of supporting and ripening large crops , but is proven also to be very effective in close-planted (5,000+ vines / ha) vineyards where soil fertility is low or vines are otherwise limited by strictly controlled irrigation
  • With its longer phenological cycle and excellent tolerance of cool autumn conditions, GRAD® 44-53 will keep scions photosynthesising and ripening their fruit for up to 6 weeks longer than V. riparia or V. riparia x V. rupestris stocks, and most of the V. riparia x V. berlandieri hybrids as well
  • Much better adapted to cool spring and autumn conditions than the comparably drought resistant V. berlandieri x V. rupestris stocks (110 R, 140 Ru, 99 R, 1103 P, etc.) and thus a much better choice in most of New Zealand for drought resistance and reliable ripening in cool climate vineyards
  • Vines grafted with GRAD® 44-53 rootstock are available in New Zealand through Stanmore Farm nursery under license from GRAD®
  • Website: stanmorefarm.co.nz
    E-mail for orders or inquires: orders@stanmorefarm.co.nz
    Phone: 0800 Stanmore (0800 782 666)
    Mobile: Harry Gibbs 022 132 4503
  • For more information on this rootstock, or advice about its use and suitability for your vineyard, contact Dr. Gerald Atkinson at grapevines@hotmail.co.nz
  • A comprehensive non-propagation contract must be signed off as part of your purchase order.

Source and History

This rootstock was imported as a D.N.A. -identified certified high-health vine by GRAD in the mid-2000s. After the only vine supplied ex-quarantine was mis-directed to a Blenheim nursery, GRAD reacquired the vine and spent several years rebuilding its condition and robustness (as it was received in extremely poor condition ex-Marlborough). Numerous G1 offspring were propagated and trialled, especially with an eye to performance under extremely harsh and dry conditions. Finally, GRAD selected only the most robust and drought resistant trial vine to become the foundation source for GRAD® 44-53.

This stock, bred by Vincent Malegue, was obtained by back-crossing Riparia Grand Glabré with 144 Malegue (a hybrid of Vitis cordifolia michaux and Vitis rupestris scheele).  After languishing in relative obscurity for the early decades of the 20th century, Malegue 44-53 became one of the most used rootstock in France after WWII, but as Gallet notes, the greater vigour of V. berlandieri x V. rupestris stocks has seen it less used there among the range of drought resistant rootstocks since the 1960s. Elsewhere 44-53 is in use particularly in South Africa, California, and Brazil, and to a lesser extent in Germany, Spain, Greece, and Turkey as well as several eastern European countries. In some of these countries, it is valued and used for its resistance to nematodes as well as its drought tolerance.

 

Health status

The GRAD® 44-53 rootstock clonal line is free of detectable virus by PCR test. Free of GLRaV1,2,3, and GVA by subsequent multiple E.L.I.S.A. tests on all 30 first generation mothervines (now at Stanmore Farm nursery).

 

Characteristics

Malegue 44-53 is highly drought-resistant (due to its V. cordifolia genes) but both the V. cordifolia and V. riparia bloodlines also carry though in its being very adapted to cool climate conditions, unlike the V. berlandieri x V. rupestris drought resistant stocks which prefer notably warmer spring and (especially) autumn conditions. It excelled in Oregon rootstock trials where it ripened Pinot noir earliest of all stocks (e.g., half a week earlier than Riparia Gloire). In New Zealand we have closely observed its performance in North Canterbury, Marlborough, and Hawkes Bay. In Marlborough, in a very stony hard Waihopi Valley site it has given Sauvignon blanc vines that are about 20% more robust than, but nevertheless just as balanced as, Sauvignon blanc on Schwarzmann growing side-by-side. Ripening, sugar accumulation, juice pH and t.a., are statistically the same as the Sauvignon on Schwarzmann also.  (The 44-53 will be using rather less water than the Schwarzmann however.) Very similar results have been obtained in North Canterbury on deep stony soils in a closely monitored comparison with m/s Syrah on Riparia Gloire in one planting, and on 44-53 in the other. Consistently, the key difference is 44-53’s remarkable tolerance of high soil moisture deficits  — it has easily tolerated up to -120mm deficit for two and a half months in North Canterbury. In these severe conditions, what has been particularly striking is its ability to recover from prolonged drought without either it or its scion suffering significant, or lasting, physiological damage. By comparison, the V. riparia,  V. riparia x V. rupestris, and most of the V. belandieri x V. riapria, rootstocks that are so widely planted throughout New Zealand suffer serious and cumulative damage in drought conditions. This then of course causes significant stress and physiological damage in their scions. Such damage is becoming an increasingly frequent and serious issue as drought, and corresponding increased restrictions on supply and use of irrigation water, is fast becoming a regular feature of many New Zealand vine growing regions.  The use of GRAD 44-53® rootstock is a fundamental remedy to this increasingly common and serious problem.

Professor D.P. Pongracz notes that the root system of 44-53 is “deep-growing, strongly developed, consisting of large numbers of well branched … roots which are very tough”.¹  Consequently, 44-53 explores and exploits far more of the subsoil than the rootstocks which are by far most commonly used in New Zealand. It is most advisable therefore to ensure that before planting vines grafted to GRAD® 44-53 the vineyard subsoil is deep-ripped (ideally with a winged ripper) or, in less stable and sheet-erosion-prone soils, planting-holes should be augered with a 30cm diameter auger to as deep as 2 metres or more, as this stock will definitely send it roots down to exploit this deep-loosened soil profile. One consequence of this is that once established, vines on GRAD® 44-53 rootstock are far less vulnerable to under-vine weed competition than those on V. riparia or V. riparia x V. rupestris stocks. Indeed, permanent under-sowing with shallow-rooted grasses and the like is a realistic option once vines grafted to 44-53 are established, provided it is understood that the presence of such a shallow-rooted total-cover crop means that it has first access to light to moderate rainfall in the vineyard. In organic vine-growing regimes, where undervine cultivation is a difficult and expensive process, deep-rooting low-water-demanding stocks like GRAD® 44-53 are an obvious and smart choice  — but only after good robust vine establishment has been achieved. Young vines, irrespective of the stock they are grafted to, are highly vulnerable to weed competition, and proper weed control even for stocks like 44-53 remains vital in the first few years of vine establishment. After that however, the likes of GRAD® 44-53 (and GRAD® 106-8, GRAD® 125AA, and the currently under development ‘super stock’ GRAD® DRC5) are far more amenable to shallow-rooted under-vine cover crops than any of the V. riparia or V. riparia x V. rupestris stocks, 420A, true SO4, Geisenheim 5C and the like.

GRAD® 44-53 performs very reliably in mid-pH soils, with pH 6.5 – 7 ideal. (It is modestly tolerant of active soil Calcium.) Like quite a few of the stocks now used in New Zealand (e.g., Riparia Gloire, 125AA, Schwarzmann, etc.), it will show Magnesium deficiency if it is grown in acid soils and also in high pH soils — in conditions which of course would be remediated as part of good vineyard management. It is not the case that in well-managed, typical, vineyard pH soil conditions 44-53 suffers from Magnesium deficiency any more than any of the afforementioned stocks, if at all. Misleading claims about its Mg-deficiency tendency derive from the ill-advised one-time wide use of 44-53 in France on acidic soils in the Pyrenees-Orientale region. They simply are not borne out by the clear evidence of its use in normal, near-neutral-pH, vineyard soil conditions. In North Canterbury, planted in deep, heavy and very stony, highly sodic soil with a pH of up to 7.8, GRAD® 44-53 has flourished as gypsum and Calcium thiosulphate additions have been used to remediate the highly sodic conditions and lower the pH to neutral. In short: in well-maintained New Zealand vineyard soils of pH 6.5 -7, GRAD® 44-53 shows no Magnesium deficiency problems, very closely matches the ripening performance of V. riparia and V. riparia x V. rupestris stocks, gives balanced vines of about 20% greater robustness than V. riparia or V. riparia x V. rupestris stocks, and shows extraordinary tolerance of sustained severe soil moisture deficits with no lasting deleterious effects to it or its scions.

 

Qualitative potential

The outstanding performance of GRAD® 44-53 rootstock proves it is a highly reliable, moderate-vigour, robust, and strongly drought resistant rootstock well suited to vineyard environments in New Zealand from Hawkes Bay to Central Otago. In addition, it has the further advantage for New Zealand vineyards that, unlike the V. berlandieri x V. rupestris drought resistant stocks, it is very well adapted to cool climate conditions. It buds out well in cold springs, gives excellent scion fertility, and in cold autumns it especially stands out for its ability to continue to keep its scions photosynthesising and ripening their fruit for well over a month after V. riparia, V. riparia x V. rupestris, and most V. berlandieri x V. riparia stocks have shut down and taken their scion into senescence .

 

Ripening period

Ripening is either the same as, or often is advanced by slightly more than would be the case for the same scion, on V. riparia, or V. riparia x V. rupestris, or V. riparia x V. berlandieri stocks. Ripening appears to be earlier for scions on GRAD® 44-53 than on any of the V. berlandieri x V. rupestris stocks, so that like GRAD® 106-8, this a highly drought resistant stock distinguished by its adaptation to cool climate conditions.

 

Availability

GRAD’s licensed New Zealand nursery, Stanmore Farm, has extensive numbers of GRAD® 44-53 mothervines in production. For current season and forward orders, contact Stanmore Farm for  details regarding grafting quantities available.


GRAD® 44-53 first-generation rootstock mothervines in the GRAD® r&d nursery in 2012, before dispatch to Stanmore Farm nursery.


Vines grafted with GRAD® 44-53 rootstock are available through Stanmore Farm nursery under license from GRAD®

Website: stanmorefarm.co.nz
E-mail for orders or inquires: orders@stanmorefarm.co.nz
Phone: 0800 Stanmore (0800 782 666)  
Mobile: 027 544 0140

For more information on this rootstock, or advice about its use and suitability for your vineyard, contact Dr. Gerald Atkinson at grapevines@hotmail.co.nz

Please note that a strict and comprehensive non-propagation contract must be signed off as part of your purchase order.

GRAD® is a New Zealand registered trademark uniquely and exclusively used to identify the vines in the GRAD® vine collection. Use by unauthorised parties to identify any vine material, or other use for commercial gain, is an infringement of this trademark.

Genetic ‘fingerprinting’ and clonal traceability

Vine pirates BEWARE! It is now possible to genetically fingerprint, uniquely identify, and detect grapevine clones using the latest-developed molecular genetic sequencing techniques. See the breakthrough research paper by Michael J. Roach et al, “Population Sequencing Reveals Clonal Diversity and Ancestral Inbreeding in the Grapevine Cultivar Chardonnay”, published November 20, 2018 at
https://doi.org/10.1371/journal.pgen.1007807