41 B MGt

41 B Millardet et de Grasset

This variety results from the crossbreeding of Vitis vinifera cv. Chasselas and Vitis berlandieri.

Feuille
Apex
Fleur
Feuille
Apex
Fleur
Genetic origin

The genetic origin of the variety is also indicated when known thanks to hybridiser data or genetic analysis either published or obtained by the teams at INRAE in Montpellier (UMR AGAP) and at the Vassal-Montpellier Grapevine Biological Resources Centre (CRB-Vigne).

This variety results from the crossbreeding of Vitis vinifera cv. Chasselas and Vitis berlandieri.

Name of the variety in France (and usual name)

The rootstock variety is presented by the abbreviation or name under which it appears in the national catalogue and which is also the most commonly used in French grapevine nurseries and French viticulture. There is no official list of synonyms for rootstock varieties.

41 B MGt

Breeder\/breeder and year obtained

The name of the breeder and/or selector is indicated, as is the year in which the variety was bred.

Alexis Millardet and Charles de Grasset, 1882.

Estimated surface area of the French vineyard grafted with this rootstock and main regions of use

The figures are estimated based on the computerised vineyard register and bibliographical data.

80 000 ha . Champagne, Bourgogne Franche-Comté, Midi-Pyrénées, Val de Loire, Aquitaine, Charentes, Provence-Alpes-Côte d’Azur, Languedoc-Roussillon, Rhône-Alpes.

Evolution of mother vine surfaces

The figures provided are taken from vineyard land registers (IVCC, ONIVIT, ONIVINS), general agricultural censuses (SCEES-INSEE) and the current computerised vineyard register (DGDDI, FAM). Regional vine planting data is available on the following site: https://visionet.franceagrimer.fr/Pages/DonneesInteractivesDocs.aspx?sousmenu=observatoire%20de%20la%20viticulture.

Year
ha

1945

152

1955

504

1965

634

1975

745

1985

379

1995

229

2005

196

2015

139

Eléments de description ampélographique

Only the main ampelographic elements enabling the rootstocks to be characterised and identified are provided. They are described according to the ampelographic descriptor code recognised by the International Organisation of Vine and Wine (OIV), the International Union for the Protection of New Varieties of Plants (UPOV), the Community Plant Variety Office (OCVV) and Bioversity International (for more information, see the "Ampelographic glossary" menu). The photographs of buds, flowers and adult leaves were taken indoors by the INRAE team at Domaine de Vassal from material sampled from the ampelographic collections of the Vassal-Montpellier Grapevine Biological Resources Centre. Note: the scale of the photos is not the same for the three organs shown. The photos of buds have been reduced (x 0.5 approx.), as have those of the adult leaves (x 0.25 approx.), while those of the flowers have been enlarged (x 4 approx.).

The identification is based on:
- the tip of the young shoot that is open, with a piping anthocyanin coloration and a high density of prostrate hairs,
- the bronzed young leaves,
- the shoots with a very ribbed surface, a circular or slightly elliptic section and no erect and prostrate hairs,  
- the fairly developed tendrils,
- the circular or wedge-shaped, entire adult leaves, with an almost completely involute leaf blade but revolute on the edges, a slightly open U- or lyre-shaped petiole, with sometimes naked petiole veins, short teeth with straight sides, 
- the female flowers,
- the small, round-shaped berries, with a blue black skin,
- the woody shoots with a fairly large diameter, browny grey internodes and darker nodes.

Genetic profile

The genetic profile of the variety is provided for the 9 microsatellite markers (or SSR markers) selected under the European programme GrapeGen06 (http://www.eu-vitis.de/index.php) and by the OIV. The absolute size values of the alleles may vary slightly from one laboratory to another, but the relative differences between the two alleles of one single microsatellite are constant. The genetic analyses were conducted by the INRAE Montpellier team (UMR AGAP) and the IFV’s Plant Material Centre.

Microsatellite VVS2 VVMD5 VVMD7 VVMD27 VRZAG62 VRZAG79 VVMD25 VVMD28 VVMD32

Allele 1

133

223

231

254

194

256

254

241

239

Allele 2

141

225

239

255

194

260

255

267

255

Resistance to soil pests

The degree of tolerance to the root form of phylloxera and resistance to nematodes (Meloidogyne hapla, Meloidogyne incognita and Meloidogyne arenaria), to Agrobacterium vitis (the bacterium responsible for burls) and to certain soil fungi is stated on the basis of observations or bibliographical data.

41 B MGt is moderately to highly tolerant to the root form of phylloxera. It is sensitive to Meloidogyne incognita, Meloidogyne arenaria and Meloidogyne hapla nematodes and seems susceptible to Agrobacterium vitis.

Aptitudes for vegetative multiplication

The level of wood production by the rootstock strains is stated (source: ENTAV-ONIVINS survey of grapevine nurseries, April 2001). The suitability for cleaning, disbudding, cutting and grafting is also specified. Further details are provided if the rootstock variety requires special precautions during grafting and layering.

The length and diameter of the internodes are moderate to large and the wood production is low to medium (15 000 to 50 000 m/ha) with sometimes a certain proportion of dry canes. In mother plantation, 41 B MGt is both sensitive to water stress and to humidity excess in the soil. It is sometimes susceptible to the declining of the vine trunks. 41 B MGt canes easily lignify. Once collected, they must be properly stored and be sufficiently rehydrated before use. Their cleaning and disbudding is fairly easy. 41 B has a low to moderate cutting capacity, with sometimes necrosis at the bottom of the plants, but it displays good aptitude for grafting. A special care (duration, hormoning) must be paid during the stratification phase in order to avoid large calluses.

Clonal selection in France

All certified clones are listed, as are the surface areas of the mother vine of clones that are propagated. For the moment, clonal selection of rootstock is conducted solely for sanitary purposes.

In France, the 16 certified 41 B MGt clones carry the numbers: 80, 86, 87, 88, 153, 172, 193, 194, 195, 210, 212, 231, 232, 233, 238 and 1177. Among those, the clones multiplied are:
- clone No. 80: 54 ares of mother vines producing certified material, in 2017,
- clone No. 153: 15 ha 50 ares of mother vines producing certified material, in 2017,
- clone No. 172: 60 ares of mother vines producing certified material, in 2017,
- clone No. 194: 103 ha 59 ares of mother vines producing certified material, in 2017,
- clone No. 195: 16 ha 82 ares of mother vines producing certified material, in 2017.

Datas are extracted from: Les chiffres de la pépinière viticole, 2017, Datas and assesment of FranceAgriMer, may 2018.

Adaptation to the environment

This paragraph provides information on the behaviour of the rootstock variety in relation to the structure, texture and composition of the soil, its mineral content and the soil’s pH. It also states the behaviour of the rootstock when faced with an excess or lack of water during the vegetative period. Chlorosis Iron chlorosis is related to problems of iron assimilation due to low iron content and/or high carbonate content in soil. Total calcium carbonate content alone gives only a partial idea of the chlorosis-inducing power of the soil. The active calcium carbonate content corresponds to the percentage of carbonate present in the fine fraction of the soil (clays, fine silts). Depending on the characteristics of the parent rock and its geological origin, this represents a variable percentage of the total calcium carbonate. The chlorotic power index (IPC) is a calculation which takes into account the active calcium carbonate content and the easily extractible iron content of the soil. These three values provide an insight into the risk of chlorosis and allow growers to choose the most suitable rootstock variety accordingly. Tylosis and apoplexy These apoplexy phenomena are linked to problems of water circulation through the plant when evapotranspiration is high (dry wind following heavy rainfall in the summer season) and the absorption of water through the roots is limited. In this case, the high pressure in the vessels causes air bubbles (cavitation) and tyloses (invagination of the membrane of neighbouring cells in the vessels) to form, which causes a slowing of sap circulation and water stress in the leaves.

41 B MGt is characterized by its adaptation to limestone soils and its resistance to chlorosis. It resists up to 60% of "total" limestone, 40% of "active" limestone and an ICP of 60. It also absorbs well magensium in the soil. 41 B MGt is however sensitive to temporary water excess during the spring and its reistance to drought is moderate. It does not seem very adapted to too compact soils.

Interaction with the graft and production objectives

The rootstock may interact with the characteristics of the graft in terms of precocity of the vegetative cycle and the growth and development of the branches, as well as yield factors (fertility and berry size). In some cases, the risks of incompatibility or poor affinity of the rootstock variety with a graft variety are specified.

41 B MGt confers a moderate to high vigor to the grafts.It usually shows a good affinity with grafts even if problems have been noticed with Merlot and Pinot which is however grafted in significant amounts with this rootstock. The first plant development is rather slow. 41 B MGt promotes the compactness of grape clusters. It also tends to delay the vegetative cycle of grafts. Compared to other rootstocks, the varieties grafted onto 41 B MGt produce less rich in sugar and slightly more acidic fruits.

Bibliographic references

The rootstock may interact with the characteristics of the graft in terms of precocity of the vegetative cycle and the growth and development of the branches, as well as yield factors (fertility and berry size). In some cases, the risks of incompatibility or poor affinity of the rootstock variety with a graft variety are specified.

- Catalogue des variétés et clones de vigne cultivés en France. Collectif, 2007, Ed. IFV, Le Grau-du-Roi, France.
- Documentary collections of the Centre de Ressources Biologiques de la Vigne de Vassal-Montpellier, INRAE - Montpellier SupAgro, Marseillan, France.
- Cépages et vignobles de France, tome 1. P. Galet, 1988, Ed. Dehan, Montpellier, France.