The effect of plant growth regulators on productivity of lavender (Lavandula angustifolia Mill.) in the conditions of the Southern Steppe of Ukraine

Abstract

The current state of the essential oil industry in Ukraine requires the expansion of areas for essential oil crops. Nowadays, the demand for natural vegetable raw materials and lavender essential oil is growing. Therefore, the aim of the research was to study the morpho-biological features and productivity of lavender plants by treatment with plant growth regulators Radostim and Stimpo during the third-fifth years of the growing season in the Southern Steppe of Ukraine. The research was conducted during 2018–2020. The material for the research work was lavender plants such as Lavandula angustifolia Mill., the varieties of Sinieva and Vdala. The field experiment was done with the method of split randomized blocks. The research was accompanied by phenological, biometric, structural and laboratory observations in accordance with generally accepted methods. Treatment with the growth regulator Stimpo has the greatest stimulating effect on the processes of growth and productivity in lavender plants. Using this method, the highest yield was formed in all years of vegetation from 6.70 to 7.90 t ha-1 at standard humidity, which is by 14.8–21.1% more than in the control. The mass fraction of essential oil in vegetable raw materials is quite high (1.85–2.32%), it differs in lavender varieties and does not depend on treatment with plant growth regulators. The largest harvest of essential oil in all years of vegetation was obtained by treating plants with the growth regulator Stimpo from 137.30 up to 147.36 kg ha-1, which is by 15.9–16.7% more than in the control.