Investigation of dwarfness effect of trinexapac-ethyl on Zinnia elegans ‘State fair ‎mix’‎

Application of regulators in production of pot plants have been increasing due to lowering growth, improving branching and the number of flowering branches. In order to study the effect of levels and application method of trinexapac-ethyl regulator on height control and morphophysiological characteristics and flowering of Zinnia elegans, a factorial experiment based on completely randomized design with three replications was performed. Zinnias seedlings were planted in polyethylene pots and subjected to trinexapac-ethyl with levels of zero, 2×10-3, 1×10-3, 0.5×10-3 and 4.5×10-4 g when the first bud emerged. Trinexapac-ethyl was applied in both foliar spray and soil application. According to the results, 1×10-3 and 2×10-3g trinexapac-ethyl caused significant reduction in plant height. As trinexapac-ethyl level increased, number of branches and flowers were increased accordingly most of which was under the latter treatment. Branch length and leaf number was not affected. The concentrations 1×10-3 and 2×10-3g increased chlorophyll and shoots sugars, but not on root. Similarly, soil application of Trinexapac-ethyl did not showed positive effects. In light of obtained results, foliar spray application of Trinexapac-ethyl may serve as a suitable way to produce dwarf and pot Zinnia elegans  ‘State fair mix’. Based on the obtained results, application of Trinexapac-ethyl as foliar application can control and reduce the height of the Zinnia elegans ‘State fair mix’.