Vierul-3

Origin History and Economic Significance

The rootstock grape variety Vierul-3 was bred in 1965 at the Moldavian Research Institute of Viticulture and Winemaking (NIIViW) by crossing the local variety Moldavsky (Korna Niagra) with the Riparia Gloire de Montpellier rootstock. The authors of this selection form are G. M. Karadzhi, I. P. Gavrilov, and O. S. Rebeza. In 1981, the variety was accepted for state trials. It is recommended for use as a rootstock in all viticultural zones with carbonate soils to replace the widely used Berlandieri × Riparia Kober 5BB rootstock.

Vierul-3 is characterized by good graft compatibility with most European grape varieties, which guarantees a high yield of grafted saplings in nursery (shkolka) conditions, which subsequently show stable growth and high productivity. Possessing an earlier start of wood maturation, this rootstock effectively contributes to the accelerated ripening of berries and better shoot maturation of scion varieties.

Ampelographic Description of the Vierul-3 Variety

• Young shoot (tip): The tip of the young shoot is green, with faint pubescence. The first young leaves are shiny, with a faint golden tint. The developing young shoot is colored green with a distinct dark violet shade on the sun-exposed side.
• Formed leaf: The leaves are large, oval, three-lobed, with a low degree of dissection. The upper surface of the leaf blade is dark green, slightly shiny, with a faint net-wrinkled (reticulate) structure. Pubescence on the lower side of the leaf is completely absent.
• Sinuses and petiolar sinus: Upper sinuses are open, formed as an incoming angle. The veins at the very base of the leaf blade are wine-violet. The petiolar sinus is open and lanceolate (arrow-shaped).
• Teeth: The teeth at the ends of the lobes are large, noticeably elongated into a sharp point. The teeth along the margin of the leaf blade are small and dome-shaped.
• Flower: Male flower type with five stamens; the length of the filaments exceeds 3 mm.
• Shoots: Annual shoots are uniform in thickness, characterized by a small pith and longer than average internodes (12–14 cm). Few lateral shoots (pashynks) are formed on the main stems.

Features of Agricultural Technology of the Vierul-3 Grape Rootstock

The variety is unpretentious to soil conditions and does not suffer from chlorosis when the active lime content in the soil is up to 20% according to Galet. It demonstrates high resistance to the root form of phylloxera (infestation rate is evaluated at 1 point); however, it is moderately affected by the leaf form of the pest (3 points). Due to somewhat weakened resistance to downy mildew (infestation rate is 2–3 points), the vines require one preventive spraying with Bordeaux mixture during rainy years.

Due to the low formation of lateral shoots, the need for lateral disbudding (pashynkovanie) is low, especially when using vertical trellises. The maturation of annual growth begins early—in the second half of August—and the overall degree of shoot wood maturation is high, reaching 88–90%. Under non-irrigated conditions of the central zone of Moldavia, with a vine spacing area of 2.6 × 1.7 m, the yield of half-meter cuttings suitable for grafting is 100–110 thousand pieces per hectare of the mother plantation. The cuttings possess good rooting capacity of the Vierul-3 variety.