The application of growth regulators in apple orchard

The growth regulators can affect many physiological and biochemical processes in plants, either by stimulation or by inhibition of particular processes, resulting in the changes in the synthesis of physiologically active substances or in the morphological traits of plants or fruits. The efficacy assessment of the growth regulator with prohexadione-calcium as the active ingredient (Product name Professon) on the length of the apple shoots was carried out during vegetative season of 2022 on four localities according to the OEPP/EPPO methods. The product Professon was applied in the recommended application rate of 1.25+1.25 kg/ha when the shoots were in the intensive growth stage. During vegetation 4 assessments were made by measuring 100 shoots on 10 trees. The lengths of the shoots were compared with the ones of the untreated apple trees. Also, the phytotoxic application rate was studied at all the localities. As a result, after the harvest, it was determined that the growth regulator Professon reduced the length of the shoots for 40.57-70.25% compared with the control, depending the apple variety.