Mechanical properties of Okuzgozu (Vitis vinifera L. cv.) grapevine canes

Abstract

Background: The mechanical properties of Okuzgozu grapevine canes influence pruning and harvesting techniques, grape quality, and the feasibility of using mechanical harvesters. Methods: This study determined the optimal cutting qualities for the native Okuzgozu grape variety (Vitis vinifera L.) over a range of phenological stages and cane diameters. The cutting tests of canes were performed at different growth periods (veraison, 15 days after veraison and harvesting time). A universal material testing equipment was used to investigate the cutting characteristics of the material. Results: The results indicate that both phenological stages and diameter significantly impacted measured cutting characteristics of grapevine canes. Cutting strength, cutting force, cutting energy and upper bio-yield force gradually decreased with phenological stages. All average maximum values were obtained during the veraison stage. At this stage, the highest values for cutting strength, cutting force, cutting energy, and upper yield were measured at 13.16 MPa, 774.55 N, 5.94 J, and 631.60 N, respectively. The lowest values were recorded at 9.63 MPa, 568.42 N, 3.33 J, and 513.13 N. A close relationship was observed between cane diameter and cutting energy. The energy requirement decreased linearly with decreasing cane diameter. Conclusion: The maximum cutting energy and force values were calculated at an internode 5 (IN5) as 7.34 J and 995.49 N respectively, the minimum cutting energy and force values were calculated at internode 1 (IN1) as 1.85 J and 385.52 N, respectively.

Keywords

• Cutting energy
• Cutting force
• Grape
• Harvest
• Phenological stages