SUMMARY
Aim of study: to find out the effects of four phytohormones, including Indole Butyric Acid (IBA), Indole Acetic Acid (IAA), and Gibberellic acids (GA3, GA4) on seedling growth of Hungarian oak which has a natural distribution in the northwestern of Turkey.Area of Study: Mature acorns of Hungarian oak were collected from a natural stand in Zonguldak-Eregli at northwestern region of Turkey.Material and Methods: Collected acorns of the species were pretreated with 300 ppm of each phytohormone for 24 hours and sown in Yenihan State Forest Nursery of Bartin, Turkey. Two years old bare-root seedlings were used for the measurements of seedling height, root collar diameter, stem, root and seedling fresh weights, and stem, root and seedling dry weights of two bare-root seedlings for each phytohormone treatment.Main results: Best performance of all studied seedling traits with the exception of root collar diameter was revealed in seedlings with IBA. In contrast, treatment of seeds with GA3 reduced all seedling traits apart from seedling height and root collar diameter. According to Dickson quality index, IBA was displayed to be the most beneficial phytohormone application for generating Hungarian oak seedlings with better mechanical resistance during transplanting.Research Highlights: IBA should be adopted in planting the seedlings of Hungarian oak for plantation activities.Keywords: Field performance; Morphology; Phytohormone, Quality; Quercus frainetto.Abbreviations used: Dickson quality index (DQI), gibberellic acid (GA), indole acetic acid (IAA), indole butyric acid (IBA), root collar diameter (RCD), root dry weight (RDW), root fresh weigh (RFW), seedling dry weight (SEDW), seedling fresh weight (SEFW), seedling height (SH), Statistical Package for the Social Sciences (SPSS), stem dry weight (STDW), stem fresh weight (STFW).