Glera

Key Characteristics

Glera is an ancient white technical grape variety of Italian origin, belonging to the Vitis vinifera species. According to official regulatory data from the Ministry of Agriculture of Italy, this vine is registered in the national catalog under code 200 as of May 25, 1970. The historical and primary commercial cultivation area is concentrated on the hills of northeastern Italy. Within the Veneto region, official classification recommends its planting in the provinces of Treviso, Venice, Padova, Vicenza, and Belluno, while in the Friuli-Venezia Giulia region, it is recommended in the Udine province. The variety is also authorized for cultivation in the provinces of Gorizia, Trieste, Pordenone, and on the island of Sicily. The harvested yield serves as the foundation for the production of renowned sparkling and still wines within the prestigious DOCG zones of Asolo - Prosecco, Conegliano Valdobbiadene Prosecco, and Colli di Conegliano, as well as under the wider structure of DOC Prosecco, Venezia, Carso, Colli Euganei, and Montello Colli Asolani. The ripening period is late, with harvest maturity on the Veneto hills traditionally occurring in the second decade of October. The yield potential is high and abundant, though productivity depends heavily on weather conditions during flowering. Clusters are medium-sized, elongated, and loose; the berries are predominantly round and golden-yellow. Technological must parameters are characterized by high quality, with sugar levels at 18–22% and titratable acidity remaining within 7.0–9.0 g/l.

Morphological Description

Для идентификации сорта составлено детальное описание характерных для сорта Глера морфологических признаков:

• Canes (woody shoots): Mature shoots are characterized by medium thickness, good resistance to cutting, and distinct longitudinal striations. During active vegetation, characteristic red stripes develop at the base of the cane. The internodes are of medium length. The nodes are moderately thickened. The vegetative buds are pubescent and prominently protruding. The bushes display high vigor, with shoots developing sparsely on the plant.
• Herbaceous part (young shoots and leaves): Budburst occurs during the first decade of April. The apex of the young shoot is very small, pale green, and covered with light cottony pubescence. The tendrils are firm, numerous, and morphologically bifid.
• Mature leaf: The leaves are large but irregular in size, three-lobed, with a distinct tendency toward rounded lobes. The upper surface of the blade is intensely green, turning a characteristic iron-gray shade in late autumn. The blade is dense, coarse, and wavy, with a tendency for the lobes to fold along the primary veins. The lower surface is light green with prominent tomentose pubescence. The lateral sinuses are of medium depth, elliptical, and slightly open at the margins. The basal lobes form a completely closed petiole sinus. The marginal teeth are wide, deep, and sharply acute, with each individual tooth bearing a characteristic hooked tip. The veins are strongly prominent. The petiole is of medium length, firm, green, and ensures late defoliation.
• Cluster and berry: The developed cluster is medium-sized, elongated pyramidal in shape, and loose in density with a free arrangement of berries. Clusters are consistently equipped with a distinct upper branch (wing). The primary peduncle is firm and of medium length. The pedicels are elongated and green. The berries are round in the main variety (oval with a dotted pattern in the Prosecco lungo sub-variety). The skin is thin, golden-yellow, highly resistant to decay, and covered with a light layer of waxy bloom (pruine). The pulp is soft, the juice is clear, and the flavor profile is simple and vinous. Each berry contains 1 to 3 regular seeds.

Agricultural Characteristics

The reviewed grape variety prefers southern and western slopes, where it demonstrates the highest qualitative yield attributes. Deep clayey-calcareous soils are optimal, whereas on flat plains, the commercial value of the vineyards decreases. The plants display exceptionally low resistance to the fungal pathogens powdery mildew (oidium) and downy mildew (peronospora), requiring regular protective treatments. The vine withstands winter frosts and late spring cold spells relatively well. Flowering takes place in the first decade of June and is characterized by instability; in rainy weather, fruit set drops significantly, leading to shot berries or cluster thinning. The grape variety Glera requires rather long pruning of fruiting canes. Historically, training methods include high-trained systems on living trees or on "scarasse" supports (long stakes driven in an X-shape with a crossbar). The plants are sensitive to soil depletion and demand mandatory management, including fertilization and soil mounding around the trunks to compensate for erosion caused by rains. Data regarding resistance to phylloxera and botrytis are absent in the referenced official catalogs.

Winemaking and Product Attributes

The grape variety Glera is used exclusively for winemaking, holding leading positions by production volume in northeastern Italy. According to statistical data, vineyard areas under this culture showed explosive growth: from 6,184 hectares in 1970 to 18,255 hectares by 2010. Current nursery figures confirm high commercial demand for the vine; in 2023, the production of grafted benchgrafts exceeded 8.15 million units of the certified category and over 9.46 million units of the standard category. The finished dry wine features proper body, moderate alcohol content (9–11% ABV), distinct acidity (7–8 g/l), and an elegant varietal aroma that develops with aging. In winemaking practice, the variety requires strict adherence to processing technology and quality clarification of the must; otherwise, the young wine rapidly degrades during the summer season. The sugar accumulation in the berries also allows the harvested yield to be used for air-drying on mats to produce traditional sweet "holy wine" (vino santo) suitable for long-term aging.