The outstanding performance of the GRAD® 106-8 rootstock has proven it to be highly reliable, moderate-vigour, robust, and strongly drought-resistant. In addition, it has the 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.

GRAD® 106-8 rootstock in brief:

  • Unique new highly robust GRAD® dual-clonal selection of low-moderate vigour (e.g., closely comparable to Couderc 3309)
  • Very high level of drought resistance, but (as with the similarly, but quite independently, hybridised Malegue 44-53) both its Vitis cordifolia and Vitis riparia bloodlines also carry though in its being highly adapted to cool climate conditions
  • Consistently tested either free of detectable virus by PCR test, or otherwise weakly positive for a benign strain of the minor virus RSPaV. All 36 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 to GRAD® 106-8 are performing extremely well in vineyards in Hawkes Bay, Marlborough, and North Canterbury, particularly in poor deep stony soils and dry conditions
  • Strongly developed branching and plunging root system, far more deeply-growing than that of V. riparia or the hybrids of V. riparia x V. rupestris, so it exploits far more of the subsoil 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 and enhances fertility
  • Can give either robust vines capable of supporting and ripening large crops in well managed high-production conditions (2000 – 2500 vines / ha), or can definitely be used in close-planted (5,000+ vines / ha) vineyards where the fundamental vigour control measure of strategically limited irrigation will be exceptionally well tolerated
  • With its longer phenological cycle and excellent tolerance of cool autumn conditions, GRAD® 106-8 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 Paulsen, 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® 106-8 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: 027 544 0140
    For further details and advice on utilisation 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.
  • Download Complete GRAD 106-8 In Brief Fact Sheet PDF

 

 

Source and History

The source vines for GRAD® 106-8 were discovered by GRAD when roguing a rootstock block. They almost certainly trace back to M.A.F. early 1980s experimental heat-treated 106-8 which was at one time held in several of their (now long-since removed) North Island vine collections.

The original introduction of 106-8 to New Zealand would appear to have taken place in 1931, from Australia, although by the 1960s this stock had become mislabelled, and effectively lost, at Te Kauwhata where it was originally held. It was recovered there, as an ‘unknown rootstock’, in the late 1970s – early 1980s and its identity was eventually established by ampelographer Doris Zuur who was working with Dr. Richard Smart for M.A.F. Since discovering a remnant of this material, I have had the identification as Millardet et de Grasset 106-8 confirmed by D.N.A. analysis at the Waite Institute in Australia.

106-8 was bred in 1882 by Alexis Millardet who back-crossed Vitis riparia michaux  with cordifolia rupestris de Grasset No.1 (a hybrid of Vitis cordifolia and Vitis rupestris).  Unfortunately for this stock’s fortunes, and despite Franz Richter lauding it in 1905 as “a valuable variety with a bright future”,  Millardet published articles claiming 106-8 was well adapted to ‘argilo-calcareous’ soils and thus effectively declaring that it was tolerant of significant active lime.¹  But Richter, by 1905, knew this was not correct and accurately noted that the stock was “easily affected by Chlorosis”².  This should have been just a minor setback for 106-8, but in the subsequent decade Richter extensively tested and promoted various highly lime-tolerant and drought resistant V. berlandieri x V. rupestris stocks provided to him by Gustave Foex of the University of Montpellier. Richter attached his own name to these and then, in particular, widely promoted the stocks Richter 99 and Richter 110 through his highly prominent nursery. Their excellent drought resistance (and particularly that of 110R) matched that of 106-8, but they had the huge advantage for many major French vine-growing regions of also being very tolerant of the active Calcium in their soils. As a result, Millardet 106-8 was pushed into obscurity, for in what should have been the country of its most egregious success and adoption, it was superseded and hugely out-promoted by the rise of Richter’s 99 and 110 stocks.

Outside France, and before there had been international recognition and trialling of Richer 99 and 110, Millardet 106-8 was recognised as an outstanding rootstock in extensive comparative trials in California in the early 20th century. However, the rise of prohibition in the U.S. in the 1920s put paid to this following through into any plantings of significance. In more recent times 106-8 has been extensively used (and bred from) in Brazil, as well as having lesser plantings in Italy, Spain, Australia, and South Africa. With climate change now making an increasing impact on European vineyards, cool climate adapted highly drought resistant stocks carrying Vitis cordifolia bloodlines are fast coming back into the spotlight for researchers and vine developers. Consequently, a serious revisiting of the merits and utility of 106-8 and its V. cordifolia hybrid ilk, notably at the moment in Germany, is at last taking place.

 

Health status

I regenerated and further developed two clonal lines from my original recovered material once it was D.N.A. identified as 106-8, and these foundation clones have tested either free of detectable virus by PCR, or otherwise weakly positive for a benign strain of the minor virus RSPaV. All 36 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.

 

GRAD® 106-8 first-generation mothervines in the GRAD nursery at Christchurch.

 

  

 

Characteristics

106-8’s Vitis cordifolia genes give it a very high level of drought resistance, but (as with the similarly, but quite independently, hybridised Malegue 44-53) both the V. cordifolia and V. riparia bloodlines also carry though in its being highly adapted to cool climate conditions. This significantly distinguishes 106-8 from the V. berlandieri x V. rupestris drought-resistant stocks (110 Richter, 99 Richter, 1103 Paulsen, 140 Ruggeri, etc.) which prefer notably warmer spring and (especially) autumn conditions.

Professor D.P. Pongracz notes that the root system of 106-8 is “strongly developed, well branched” and “much more deeply growing than that of the hybrids of ripara x rupestris”.³  This means it exploits a great deal 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 106-8, 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, as this stock will definitely send its roots down to exploit this deep loosened soil profile. (Reverse-screw the auger out of planting hole for easy soil retention.) A key consequence of 106-8’s deep plunging root system is that once established its vines are far less vulnerable to under-vine weed competition than those on V. riparia or V. riparia x V. rupestris stocks. Indeed, permanent undersowing with shallow-rooted grasses and the like is a realistic option once vines grafted to 106-8 are established, provided it is understood that the presence of such a shallow-rooted total-cover crop means that it — and not the rootstock — has first (or ‘interceptive’) access to 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 106-8 are an obvious and smart choice  — but good robust vine establishment must be achieved first. Young vines, irrespective of the stock they are grafted to, are highly vulnerable to weed competition, and proper weed control even for stocks like 106-8 remains vital in the first few years of vine establishment. After that however, the likes of GRAD® 106-8 (and GRAD® 44-53, 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.

In New Zealand GRAD® 106-8 is performing extremely well in deep stony soils in North Canterbury, Marlborough, and Hawkes Bay. In Marlborough, in a very stony hard Waihopai Valley site it has, along with GRAD® 44-53, given Sauvignon blanc vines that are about 20% more robust than, but nevertheless just as balanced as, Schwarzmann growing side-by-side. Ripening, sugar accumulation, juice pH and t.a., are statistically the same as the Sauvignon on Schwarzmann also.  (The 106-8 will however be using significantly less water throughout the season.) In North Canterbury, GRAD® 106-8 has shown remarkable tolerance of high soil moisture deficits: in two consecutive recent seasons it has performed outstandingly in soils with -90mm to -120mm water deficit for two and a half months through summer. In these severe conditions, what has been particularly striking is GRAD® 106-8’s ability, like that of GRAD® 44-53, 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 the scions on these non-drought-resistant stocks. Such damage is becoming an increasingly frequent and serious issue as drought, and corresponding increased restrictions on supply and use of irrigation water, becomes a regular feature of many New Zealand vine growing regions.  The use of GRAD® 106-8 rootstock is a fundamental remedy to this increasingly common and very serious problem.

GRAD® 106-8 performs very reliably in mid-pH soils, with pH 6.5 – 7 ideal. (It is only weakly tolerant of active soil Calcium; if this is an issue, use GRAD® 44-53 instead for moderate active-Ca tolerance.)

GRAD® 106-8 performs very reliably in mid-pH soils, with pH 6.5 – 7 ideal. (It is only weakly tolerant of active soil Calcium; if this is an issue, use GRAD® 44-53 instead for moderate active-Ca tolerance.) GRAD® 106-8 is particularly suitable for deep gravelly, very stony, silty soils that are prone to poor moisture retention and fast drainage and / or where rainfall and irrigation water are restricted. In North Canterbury it has also performed extremely well in deep-worked but otherwise very hard and heavy, highly sodic soils inter-filled with cricket ball to rugby ball -sized stones mixed with pea gravels and silt. Here the key to the vines’ success has been to drive out the very high soil Sodium and lower the (up to 7.8 pH) by additions of gypsum and Calcium thiosulphate. In these very harsh conditions, GRAD® 106-8 has supported m/s Syrah scions through as much as 10 weeks of soil moisture deficit as low as -120mm with excellent quick recovery once rainfall or irrigation is supplied, and with no lasting physiological damage to either the stock or scion. (Indeed, the 4 and 5 year old Syrah vines in this planting barely showed any symptoms of drought stress whatsoever, except modest wilting on one or two days when vineyard temperatures exceeded 35°C in the shade.) The popular V. riapria and V. riparia x V. rupestris stocks widely in use in New Zealand, as well SO4 and Geisenheim 5C, would suffer severe stress and lasting physiological damage under these circumstances, as would their scions. By comparison, GRAD® 106-8 takes it all in its stride.

 

Qualitative potential

The outstanding performance of the GRAD® 106-8 rootstock dual clonal line has proven it to be a highly reliable, moderate-vigour, robust, and strongly drought-resistant rootstock. In addition, it has the 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 essentially the same as would be the case for the same scion on V. riparia, or V. riparia x V. rupestris, or most V. riparia x V. berlandieri stocks. Ripening appears to be earlier for scions on GRAD® 106-8 than for the same scions on any of the V. berlandieri x V. rupestris stocks.

 

Availability

GRAD’s licensed New Zealand nursery, Stanmore Farm, has extensive numbers of GRAD® 106-8 mothervines in production. For current season and forward orders, contact Stanmore Farm for  details regarding grafting quantities available.

Vines grafted with GRAD® 106-8 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: Harry on 022 132 4503

For further details and advice on utilisation 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”