The effects of plant growth regulators and stratification on seed dormancy breaking and parameters of morphological, physiological and biochemical of seedlings of Persian walnut (Juglans regia L.)

Persian walnut (Juglans regia L.) is an economically important fruit tree of the temperate regions of the world that is cultivated for its fruit and timber. Due to physiological and mechanical dormancy, the walnut seeds often show an inconsistent or low germination percentage, making difficult the subsequent growth of seedlings. The purpose of this experiment was to investigate the influence of stratification periods (30 and 60 days) and different concentrations of plant growth regulators (Gibberellic acid and Kinetin) on seed dormancy breaking and germination of Persian walnut. This experiment was carried out as a completely randomized design with 15 treatments and 20 replicates in condition of greenhouse. Results showed that stratification periods and different concentrations of plant growth regulators had a significant difference on the most parameters investigated (P