Zornitsa
| Variety Passport | |
| Country of origin: | Bulgaria |
| Breeder: | The "Obraztsov Chiflik" Institute |
| Variety number VIVC: | 24054 |
| Prime name: | Zornitsa |
| Year of obtaining / registration: | crossing performed in 1986, recognized by IASAS in 2012 |
| Pedigree given by breeder: | Rusensko Edro × King Ruby |
| Pedigree confirmed by markers: | Rusensko Edro x Ruby Seedless |
| Species: | Vitis vinifera |
| Ripening period: | Late |
| Classification and Use: | Table, Seedless, Fresh consumption, Long-term storage |
| Resistance group: | Moderately resistant |
| Data Sources: | Vitis International Variety Catalogue (VIVC), ИЗС Образцов чифлик (Bulgaria) |
| Agrobiology | |
| Vigor: | vigorous |
| Lateral shoot formation: | moderate |
| Flower type: | hermaphrodite |
| Downy mildew susceptibility: | 4 points (highly susceptible) |
| Powdery mildew susceptibility: | 3 points (low resistance) |
| Botrytis susceptibility: | 2 points (resistant) |
| Winter hardiness: | Low frost resistance (-18...-20°C) |
| USDA Hardiness Zone: | Zone 7 (down to -17.8°C) |
| Pruning length: | mixed / Guyot |
| Recommended rootstocks: | Rupestris du Lot, SO 4, 41 B |
| Clusters and berries | |
| Bunch density: | loose |
| Average bunch weight: | 400 g |
| Berry shape: | oval, obovoid |
| Berry skin color: | gray |
| Average berry weight: | 4,9 g |
| Seed development: | rudimentary seeds |
| Seedlessness class: | III (rudiments 10.1–14 mg) |
| Flesh texture: | fleshy |
| Berry skin thickness: | Thick |
| Berry skin texture: | tough |
| Sugar content: | 20-23% |
| Total acidity: | 5,4 g/l |
| Berry Flesh Color: | Weakly colored |
| Flavor type: | Varietal |
| Ampelographic overview |
Main Characteristics
The seedless grape variety Zornitsa was bred in Bulgaria at the Experimental Vineyard of the Institute of Agriculture and Seed Science (IZS) "Obraztsov chiflik" in the city of Ruse. The hybridization program was implemented in 1986 by crossing the parental forms Rusensko edro and King ruby. Official recognition by the executive agency IASAS took place in 2012. In terms of utilization, the Zornitsa variety is classified as a typical dessert grape. The ripening period occurs in the second half of September.
The average cluster weight is 400 grams. Developed clusters are characterized by a high degree of uniformity. The berries are large, with an average weight of 4.9 grams. The skin has a specific red-grey coloration, and the flesh is crunchy. The seeds are in a rudimentary state, and their dry weight per 100 berries is 0.22 grams, which makes them completely imperceptible during consumption. The flavor qualities are harmonious, with a distinct pleasant fruity undertone. The Zornitsa grape variety demonstrates sugar accumulation at a level of 20%, which can increase to 22–23% during hot growing seasons. The titratable acidity level is 5.4 g/l.
Viticultural and Agro-technical Features
The yield of plantations under standard growing conditions is about 16 tons per hectare. It is recommended to cultivate the Zornitsa grape variety using the mid-stem Guyot or Lyra training systems. The use of drip irrigation in combination with the Lyra system provides a significant increase in vine productivity. Suitable rootstocks include SO4, Chasselas x Berlandieri 41B, and Rupestris du Lot. For successful vegetation and reaching full maturity, a sum of active temperatures in the range of 3800–3900 °C is required.
Winter hardiness is classified as increased for the European-Asian species. The plants tolerate extreme temperature drops down to -18...-20 °C; in case of severe winter damage, the vines exhibit an excellent recovery capacity. Sensitivity to fungal diseases is at an average level, typical for representatives of the species Vitis vinifera. The Zornitsa variety is resistant to berry shattering during ripening and harvesting. The harvested crop is suitable for long-term storage in cold rooms for subsequent winter sales, possesses excellent transportability, and the high sugar content allows the berries to be used for raisin drying and processing into compotes.