Grézot 1
| Variety Passport | |
| Country of origin: | France |
| Breeder: | Victor Grézot |
| Variety number VIVC: | 5015 |
| Prime name: | Grezot 1 |
| Breeding number: | G1 |
| Principal Synonyms: | G 1 |
| Year of obtaining / registration: | obtained in 1894 |
| Pedigree given by breeder: | (Couderc 1616 x Rupestris du Lot) x Ganzin1 |
| Pedigree confirmed by markers: | Couderc 1202 x Castel 216-3 |
| Rootstock type: | Phylloxera-resistant |
| Data Sources: | Vitis International Variety Catalogue (VIVC), INRAE (France) |
| Agrobiology | |
| Vigor: | semi-vigorous |
| Flower type: | female |
| Active lime tolerance: | 6% |
| Salinity tolerance: | low |
| Drought tolerance: | sensitive |
| Root phylloxera susceptibility: | 3 points (low resistance) |
| Rooting ability: | high |
| Graft compatibility with Vitis vinifera: | high |
| Recommended soil types: | Non-limestone soils, free from salinity risks, with sufficient water and potassium supply |
| Ampelographic overview |
Origin and economic importance
The rootstock variety Grézot 1 was obtained by breeder Victor Grézot in 1894. Based on genetic analyses carried out in Montpellier, it is established that this variety results from a 1202 Couderc seedling (Vitis rupestris × Vitis vinifera cv. Mourvèdre). The rootstock is susceptible to chlorosis and only resists up to 6% of "active" limestone. It is also susceptible to drought and chlorides, meaning its use must be avoided if there is a risk of salinity. A physiological characteristic of the vine is that it absorbs magnesium easily and is not very sensitive to magnesium deficiency, whereas it absorbs potassium from the soil with difficulty.
The resistance to the root form of phylloxera is evaluated as moderate; therefore, the Grézot 1 rootstock must be planted under conditions that are unfavorable for this pest. When grafted, it generally shows a good affinity to grafts and provides a moderate to high vigor. A successful practical interaction has been noted in combination with the Chasselas variety.
Ampelographic description of the rootstock variety Grézot 1
The identification of Grézot 1 is based on the following morphological characteristics:
- Young shoot (tip): The tip of the young shoot is half open with no or a very low density of prostrate hairs.
- Young leaves: They are slightly bronze on the surface.
- Shoots: The surface of the shoots is smooth, with no erect or prostrate hairs.
- Adult leaf: Adult leaves are kidney-shaped and involute (with edges rolled inwards). The petiole sinus is open. The teeth feature a specific structure, with one side slightly convex and one side slightly concave.
- Flower: Female type.
- Berry: Very small in size and round-shaped. The skin coloration is blue-black.
Nursery management attributes
The variety Grézot 1 is characterized by a low to moderate wood production in mother vines, yielding from 25,000 to 40,000 meters of useful wood per hectare. Nevertheless, collected cuttings demonstrate high technical aptitudes, possessing good cutting and grafting capacities.