Abstract:

Two experiments were conducted in two vineyards consisting of vines from the organic-certified Cabernet-Sauvignon/1103P graft combination and the conventional cultivation Cabernet Sauvignon/5BB graft combination. Vines were identified based on pre-dawn leaf water potential values according to stress levels in a Split-Plot Experimental Design. Grapevines were classified as <-0.8 MPa and >-0.8 MPa. These vines were further grouped into dryland-shallow soil and bottomland-deep soil areas, and for each area-soil type, Control, Stress 1, and Stress 2 levels were created. At harvest, the berries were divided into four groups based on their diameter: 10mm-12mm, 12mm-14mm, 14mm-16mm, and 16mm-18mm (In some measurements, no berries belonging to the 16-18mm category could be found). The grapes were grouped as Control, Stress 1 (S1 > -0.8 MPa), and Stress 2 (S2 < -0.8 MPa) based on size groups and stress levels, and certain morphological characteristics of the clusters were examined. The width and length of the clusters were not significantly affected by the area-soil type. Cluster weight, cluster volume, and number of berries per cluster criteria were influenced by stress levels. It was determined that organic vineyards with higher stress levels had fewer clusters compared to conventional vineyards. The number of berries in the clusters showed significant differences based on vineyard area and soil type, water stress levels, and berry size. In conclusion, in the Tekirdağ province, to obtain high-quality grapes from the cv. Cabernet-Sauvignon, it is considered suitable to utilize berries ranging from 10mm to 12mm in size, in conjunction with dryland-shallow soil conditions where the water potential (Ψpd) can decrease to as low as -0.8 MPa during the ripening period.