17.37

History of Origin and Agricultural Importance

17.37 is a rootstock grape variety representing a natural hybrid selected by breeders Alexis Millardet and Charles de Grasset from seedlings of the Vitis berlandieri species obtained from open pollination. In ampelographic literature, some authors suggest that the parental pair of the variety, instead of a pure Berlandieri × Rupestris, is a combination of Berlandieri × Cordifolia-Rupestris. In the National Register of Grape Varieties of Italy, the 17.37 rootstock was included in March 1971 under code 627 on the basis of a ministerial decree published in the Official Gazette (Gazzetta Ufficiale) in April 1971. The description of the vine is based on the works of researchers Cosmo, Comuzzi, and Polsinelli, published in 1958.

The agricultural value of the 17.37 rootstock lies in ensuring the resistance of vineyards to the root form of phylloxera. In its agrobiological characteristics, the variety is similar to the 301 A rootstock. It is recommended for dry, arid soils with an increased content of active lime (moderately chlorosis-inducing). The rootstock has medium vigor, forms a bushy growth habit, and demonstrates high resistance to fungal (cryptogamic) diseases of the vine.

Recorded morphological features of the 17.37 rootstock variety

The recorded main morphological features of the variety:

• Young shoot (growing tip): the apex is moderately expanded, small, cottony, greenish-pink. Apical leaves (1st–3rd) are slightly trough-shaped, cottony (a few hairs are also present on the upper side of the blade), of an intense greenish-bronze color. Leaves lower down the shoot (4th–6th) are trough-shaped, entire, rounded, small, with a U- or V-shaped petiolar sinus. On the upper side of these leaves, sparse long hairs are present, the veins on the lower side are slightly velvety, the general color is green with a bronze reflection, and the veins are entirely shaded in reddish.
• Herbaceous shoot and tendrils: the shoot is slightly curved, ribbed, slightly pubescent, greenish-brown on one side. The cross-section of the shoot is polygonal, in the herbaceous state the shoot is cottony, internodes are of a dull red-violet color on one side, and nodes are intensely red-violet. Tendrils are intermittent, bifid or trifid, slightly pubescent, greenish-violet. Flowers are male.
• Leaf: formed leaves are of small size, entire, rounded in shape. The petiolar sinus is U-shaped, the leaf blade is trough-shaped or cup-shaped. The upper side is intense green, completely glabrous and glossy; the lower side is light green, with a light velvety pubescence, veins of the first and second order are highly prominent and green. Teeth along the margin are small, obtuse, mucronate, fairly regular. The petiole is short, slightly pubescent, greenish-violet, and the groove is poorly visible.
• Mature wood: shoots are of medium length and vigor, branched, with an elliptical cross-section. The surface of the vine is striated, glabrous, of a dark brown color with greyish stripes. Internodes are short (10–12 cm). Buds are small and conical. Phenological bud burst and flowering occur late, and leaf fall occurs in medium-late terms.

Nursery Agricultural Characteristics

The 17.37 rootstock demonstrates medium indicators of wood ripening by the end of vegetation. In nursery production in Italy, vine production is carried out in the "Certified", "Basic", and "Initial" (introduced into regulatory circulation since 2005) categories. In 2023, the production of rooted cuttings of the rootstock amounted to 42,000 units of certified material and 1,004 units of basic material (in 2022 — 4,800 certified, 778 basic, and 230 units of initial material). Officially registered clones of the variety in the national register: I-ISV Conegliano 1, I-V.G.V.A. 26, I-V.G.V.A. 33, I-UBA 01, and I-D-VSM-UNIRC-CREA.