M1
| Variety Passport | |
| Country of origin: | Italy |
| Breeder: | CREA (Italy) |
| Variety number VIVC: | 25502 |
| Prime name: | Milano 1 |
| Year of obtaining / registration: | Admitted to the National Register of Grape Varieties of Italy on May 15, 2014 |
| Pedigree given by breeder: | 106-8 (Vitis Riparia × (Vitis Cordifolia × Vitis Rupestris)) × Resseguier n°4 (Vitis Berlandieri). |
| Rootstock type: | Phylloxera-resistant, Lime-tolerant |
| Data Sources: | Vitis International Variety Catalogue (VIVC), Registro Nazionale delle Varietà di Vite (Italy) |
| Agrobiology | |
| Vigor: | very vigorous |
| Lateral shoot formation: | strong |
| Flower type: | female |
| Salinity tolerance: | tolerant |
| Drought tolerance: | resistant |
| Root phylloxera susceptibility: | 1 point (highly resistant) |
| Rooting ability: | medium |
| Graft compatibility with Vitis vinifera: | medium |
| Recommended soil types: | Recommended for soils with a very high risk of iron chlorosis, as well as for regions with drought conditions and moderate chloride levels. |
| Ampelographic overview |
Origin History and Agronomic Importance
The M1 grapevine rootstock was bred in Italy by selectionists at the Council for Agricultural Research and Agricultural Economy Analysis (CRA). Official admission of the rootstock to the National Register of Grape Varieties took place on May 15, 2014. The parental forms used in crossbreeding were the maternal genotype 106-8 (derived from crossing Vitis riparia with a complex hybrid of Vitis cordifolia and Vitis rupestris) and the paternal component Resseguier n°4 (classified under Vitis berlandieri). The primary advantage of this rootstock lies in its exceptionally high resistance to iron chlorosis (the exact level of tolerated active lime is not specified in the primary source) and its good adaptation to moisture deficit conditions. The wood yield per hectare in rootstock mother vineyards is evaluated as high.
Ampelographic Description of M1 Rootstock Variety
The morphological characteristics of the rootstock were recorded during the official ampelographic evaluation according to the international OIV system:
- Young shoot (tip): The young shoot tip is semi-open. A diffuse anthocyanin pigmentation of medium intensity is observed on the tip. Prostrate and erect hairs are completely absent on the tip. Hairs on the nodes and internodes of the young shoot during the flowering period are either completely absent or extremely sparse. Tendrils form sequentially in groups of two or fewer and have a medium length.
- Young leaf: The upper surface of the fourth blade is green. The lower surface of the leaf between the main veins exhibits a low density of prostrate hairs, while erect hairs are completely absent. Hairs on the main veins on the lower side of the leaf are absent.
- Mature leaf: The leaf blade has a medium size and a cuneiform shape. The leaf is practically entire, with the number of lobes equal to one. The upper surface of the blade features a light shade of green. Anthocyanin pigmentation of the main veins on both the upper and lower surfaces of the leaf is completely absent. The profile of the blade in cross-section is flat, with no depression or blistering of the upper surface. The teeth are characterized by a mixed shape combining straight and convex sides, and the length of the teeth is medium. The petiole sinus is very open, U-shaped at the base, with no specific morphological anomalies. Lateral sinuses are absent. The petiole is shorter than the median vein and is completely devoid of prostrate and erect hairs.
- Woody shoot: The canes are circular in cross-section. The surface of the shoot is smooth, and lenticels as well as hairs are completely absent.
- Flower: The M1 rootstock variety develops inflorescences with a functionally female flower type.
Features of Viticultural Nursery Practice
The M1 grapevine rootstock is characterized by a very high shoot vigor and a strong tendency to develop lateral shoots during the growing season. In nursery production conditions, the rootstock demonstrates a high yield of canes per hectare. The rooting capacity of cuttings in commercial field nurseries is rated as medium. During bench or field grafting with scion components of the Vitis vinifera species, this rootstock variety shows medium parameters of callus formation and successful graft union development.