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• Preliminary study: The effect of gibberellic acid and girdling application on two dual-purpose grape varieties in a cool climate

  139-144

  Adrienn Mária Tóth

  Zsolt Zsófi

  Szilvia Veres

  Views:

  12

  In our 2023 experiment, Nero and Muscat Pölöskei grapevines were treated with gibberellic acid (12 mg L^-1) during flowering, followed by stem-end girdling at the onset of berry development. Photosynthetic activity was monitored regularly. Assimilation rate (A, µmol CO₂ m⁻² s⁻¹) and transpiration rate (E, mol H₂O m⁻² s⁻¹) were measured under natural light. Sugar content and acidity were assessed via refractometry, while berry dimensions and texture (e.g., berry hardness [Bh, mN]) were recorded. Gibberellin treatment increased sugar content compared to both control and girdled samples. However, girdling significantly enhanced sugar accumulation in Muscat Pölöskei compared to untreated samples. Gibberellin also induced berry elongation, increasing the longitudinal axis in Nero (19%) and Muscat Pölöskei (24%). Girdling temporarily reduced photosynthetic activity, which recovered post-healing. The elongated berries due to gibberellin treatment led to a looser cluster structure, which is beneficial for Nero, which is prone to fungal diseases due to dense clusters.

• Texture analysis as a method for grape berry characterization

  Adrienn Mária Toth

  Szilvia Veres

  Zsolt Zsofi

  Views:

  366

  The marketability of table grapes is mainly characterized by berry size, color, taste and texture. Mechanical measurements of table grape berries could provide objective information on the textural qualities of grape berries. In addition, this method might be suitable to study the effects of phytotechnical methods (such as girdling) on table grape quality. The aim of this preliminary work was to demonstrate how instrumental testing could be used to examine the effects of girdling on berry grape texture and define the textural characteristics of table grape berries. Cane girdling was carried out at veraison in two table grape varieties. Texture analysis was performed several times during the maturity. Besides this examination another five varieties were analyzed to assess their berry mechanical properties. Double compression test was used to determine berry hardness and its derived parameters. Puncture test was applied to evaluate skin hardness, skin elasticity and skin break energy. Skin thickness was also investigated. Berry hardness, skin hardness and skin thickness of the girdled grapevines were significantly affected by this technique. Most of the textural parameters showed differences among the seven cultivars.