CHANGES IN STEM MORPHOGENESIS OF OILSEED RADISH PLANTS AND THE LEVELS OF ITS BIOPRODUCTIVITY UNDER THE APPLICATION OF GROWTH REGULATION

Abstract

The results of the effectiveness of different active substances of growth regulators applied to several radish species as a special tribe of the Brassicaceae family were systematized and grouped, focusing on the forms of active substances of growth regulators, the timing of their application, and potential positive changes in morphogenesis and physiological transformations of plant organisms. The analysis was conducted using the example of common radish and its derived species forms, including the classic representative of multipurpose use – oilseed radish. During a three-year production research period, the effectiveness of the widely used and well-tested growth regulator Caramba Turbo, commonly applied in the cultivation of cruciferous crops (particularly winter and spring rapeseed), was evaluated. This preparation is a combined product containing two active ingredients – metconazole and mepiquat chloride – applied at the phenological stage of the beginning of stem elongation in oilseed radish plants. The research involved a comparative evaluation of the effectiveness of this growth regulator applied at rates of 0.6 L/ha, 1.0 L/ha, and 1.4 L/ha, with comparison to a control treatment without growth regulation. The influence of the studied application rates of Caramba Turbo was investigated on several stem traits, including stem diameter at the base, stem wall thickness, stem height, stem height to the first lateral branch, and the total number of lateral branches, with a predictive assessment of the obtained variants in terms of plant resistance to stem lodging. In addition, the levels of bioproductivity were evaluated based on the yield of leaf-stem biomass, root biomass, and seed yield, with averaged indicators calculated for the entire research period. Conclusions were drawn regarding the most effective dosage of the growth regulator Caramba Turbo for the cultivation of oilseed radish varieties on grey forest soils with 30 cm row spacing and a seeding rate of 1.5 million viable seeds per hectare. The maximum effectiveness in the positive combination of stem morphogenesis of oilseed radish varieties with the long-term achievable level of their bioproductivity was observed when Caramba Turbo was applied at a rate of 1.0 L/ha at the phenological stage of the beginning of stem elongation. Prospects for further research have been outlined with respect to identifying optimal combinations of different active substances of growth regulators when used in oilseed radish agrophytocenoses.