Effect of photons of the far red region in the spectrum of LED radiation on the growth and development of sugar beet plants (Beta <i>vulgaris</i> L. ssp. <i>vulgaris</i> var. <i>saccharifera</i> Alef.)

Relevance and methodology. The task of controlling the growth and development of sugar beet plants with the help of lighting devices is of interest from the point of view of identifying biological features of the culture and in breeding practice. The purpose of the research is to determine the response of plants to the effects of low–energy monochrome radiation at the initial stage of ontogenesis (germination of seeds (coplodia) sugar beet). In this regard, the seeds of the hybrid Smena were germinated in the dark (control) and under different variants of continuous illumination with wavelengths of 380 nm, 440 nm, 525 nm, 660 nm and 730 nm.Results. The reaction of sugar beet seeds and sprouts to illumination with monochromatic light depends on the wavelength Germination of seeds when irradiated with monochromatic far-red light leads to a decrease in germination energy by 23%, seed germination by 39%, the height of sprouts and aboveground biomass by 21.8% compared with the control (dark germination). Similar indicators were observed for the negative effect of red light. Exposure to UV-A light (380 nm) led to an increase in germination energy by 4%, but germination, on the contrary, decreased by 12%. The terrestrial biomass of sprouts also decreased (by 9.9%). Irradiation with green and blue light had a positive effect on growth: the terrestrial biomass of sprouts increased by 19.8% with a green spectrum and 7.3% blue. At the same time, there was no decrease in germination energy and germination compared to the control. The germination energy under the influence of blue light even increased by 12%. With dark germination, elongated etiolated plants were formed on the 10th day, whereas in the variants of green, blue and UV-A irradiation, harmoniously developed dark green shoots were formed.