Gercüş Mezrune Grape

Gercüş Mezrune grape is a table grape variety belonging to the species Vitis vinifera, cultivated in the Gercüş district of Batman Province in Türkiye. This grape is distinguished by its medium-round, greenish-yellow fruits with thin skin and soft flesh, as well as its homogeneous berries and shoulder-branched conical clusters.

Botanical and Morphological Characteristics

Gercüş Mezrune grape is a species within the genus Vitis of the family Vitaceae and the subgenus Euvitis. The plant has hermaphroditic flowers, enabling vineyard establishment without the need for a separate pollinator variety. Canes develop with moderate vigor and are suitable for short pruning. Clusters form on the second and third nodes of summer shoots. The cluster structure is shouldered, branched, and conical, with medium length.

The berries are uniform in size, ellipsoid in shape, and medium-round. The skin is thin and greenish-yellow. The flesh is soft and colorless. The berry stalks measure 10–12 mm in length and attach firmly to the berry, exhibiting high resistance to detachment. The number of seeds per berry ranges from 1 to 2, with seed weight varying between 22.4 and 55.3 mg. The yield of Gercüş Mezrune grape is 4–6 kg per cane.

Young leaves are bright light green, five-lobed, wedge-shaped and pentagonal. The terminal lobe is slightly inwardly curved along the main vein axis. The upper surface of mature leaves varies within the dark green to green color scale. Main veins are pinkish-red. The leaf petiole sinus is U-shaped, with a petiole length of 7–8 cm.

Physical and Chemical Properties

The berry width ranges from 10.0 to 12.6 mm; length from 10.8 to 13.6 mm; and berry weight from 2.08 to 3.22 g. Cluster width is 7.0–11.2 cm, and cluster length is 9.8–15.7 cm. The weight of a single cluster may vary between 136.4 and 503.2 g.

The juice yield is between 70% and 80%. The total soluble solids (TSS) content ranges from 16.7% to 23.2%, while total acidity is between 0.58% and 0.76%. The maturity index is between 20.70 and 32.22. Due to the high potassium content of the vineyard soils (>10%), the juice pH is balanced within the range of 3.54 to 4.01.

Antioxidant activity (EC50) has been measured at levels of 0.32–0.41. Anthocyanin content is 30.4–34.7 mg/kg, and total phenolic content is 437–582 mg GAE/kg. Color properties, according to the CIE Lab* system, are reported as follows: L* value 30.34–34.11; a* value 0.44–1.46; b* value 4.76–8.23.

Cultivation and Production Process

Vine cuttings are planted in late autumn or early spring. Prior to planting, cuttings are soaked in water for one day to ensure moisture. During planting, the graft union is positioned 3–5 cm above soil level. Planting holes are 30–40 cm wide and 50–60 cm deep.

Soil management is carried out three times annually: in autumn to retain soil moisture, in spring to aerate the soil and suppress weeds, and in summer to preserve moisture. No chemical substances or hormones are used. Cultivation relies exclusively on rainfall, with no irrigation applied.

The harvest period varies according to the degree of grape maturity. Unripe grapes are harvested between 20 August and 20 September without softening and stored for 1–2 months in cold storage at temperatures of 4–14 °C. Ripe grapes are marketed directly between 20 September and 30 October. The product is also used in the production of processed goods such as pekmez, pestil, and sucuk.

Gercüş Mezrune Grape (Subgovernorship of Gercüş, Republic of Türkiye)

Geographical Boundary, Cultural Link, and Control

The production of Gercüş Mezrune grape occurs exclusively within the boundaries of the Gercüş district of Batman Province. Consequently, all stages of production must take place within this geographical boundary. The product has a historical connection to the local culinary culture and economic value of the region. Therefore, the product carries a geographical indication.

Control is conducted by a five-member oversight body coordinated by the Batman Chamber of Commerce and Industry, comprising representatives from Batman University Agricultural Application and Research Center, Batman Chamber of Commerce and Industry, Batman Provincial Directorate of Agriculture and Forestry, and Batman Municipality. Inspections occur at least once annually and may be carried out as needed or upon complaint. Inspections focus on cutting suitability, production methods, and proper use of the designation. Expert assistance from individuals or institutions may be sought when necessary.