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.

Relevance and methodology. In order to determine the effect of increasing the proportion of far red light (different ratio of red and far red light) in the total spectrum of polychrome irradiation on the growth rates of sugar beet plants of the Smena hybrid, they were grown for 82 days under LED lighting under controlled climate conditions in a Synergotron digital device of the ISR 2.01 model with a twofold increase in the proportion of far red light compared to control.Results. An increase in the proportion of far red light led to an increase in the specific weight of leaves with a smaller area of leaves in the initial period of plant growth, higher values of the quantum yield of photosynthesis, the rate of electron transport, and a decrease in energy losses mainly to heat. The biometric indicators of plants changed depending on the period of ontogeny. In the initial period, the biomass of the aerial part prevailed, in the subsequent period, the biomass of root crops. In the experimental variant, the accumulation of biomass in the aerial parts of plants in the initial period of the experiment turned out to be less than in the control, and only at the end of the experiment was an excess of the total biomass in the experimental variant by 12.2%. There was an increase in the accumulation of root biomass compared to the control by 38.7%. The predominant part of the aboveground biomass of sugar beet was made up of leaf blades, the proportion of petioles was much less and practically did not depend on the composition of the light. At the end of the growing period, the dry matter content in root crops increased by 2.44% compared to the control, sugar content – by 0.65%. The data obtained can be used in the development of technology for artificial lighting of sugar beets when grown in closed agrobiotechnosystems in order to increase the yield and sugar content of root crops.

Relevance. The selection for productivity and stability on different stages in the breeding process includes an assessment of the adaptive capacity and genotypes ecological stability. Therefore breeding for the resistance to abiotic environmental factors is closely connected with the adaptive breeding, which has received special attention in recent years.Methodology. The work was carried out at the “A.L. Mazlumov All-Russian Research Institute of Sugar Beet and Sugar” in 2011-2020. Male-sterile forms of sugar beet were crossed with fertile diploid multi-seeded pollinators (ARRISBS selections) by topcross method. The resulting hybrids were assessed for yield, sugar content and sugar collection according by standard methods used at the “A.L. Mazlumov ARRISBS”. It is carried out the annual work, including selection of the best and rejection of the worst options for the studied characteristics. An assessment was made of lines and hybrid combinations of sugar beet for the resistance to a complex of unfavorable natural and climatic factors based on the characteristics of yield, sugar content and seed productivity.Results. The results of improving selections over ten years show an increase in the weight of the root crop and the sugar content for the original single-seeded and multi-seeded materials. Single-seeded (MS-2113, MS-Perla) and multi-seeded (OP-15465, OP-15676, OP-15202) lines with high combining ability in terms of yield and sugar content of root crops were identified. An increase in the resulting parameter - sugar collection - was noted by 2020 (to 8,8-9,0 t/ha), illustrating the positive dynamics of the breeding process of sugar beet for plants of the first life year. An increase in the weight of 1000 seeds (to 13,4-13,9 g) and separate fruiting (to 98-99%) was shown during the breeding process for plants of the second life year.Conclusion. The studied hybrid combinations have a wide reaction rate to a complex of natural climatic factors: elevated temperatures in combination with high and low humidity.

Relevance and methodology. In order to determine the effect of near-ultraviolet radiation with a wavelength of 380 nm on the growth and development of a sugar beet hybrid plant, Smena was grown for 82 days under LED lighting with phytolamps and under conditions of increased UV-A intensity of the light range (an increase in the UV/PPFD ratio (0.027) compared with the control (0.0075) while maintaining the ratio of the remaining sites spectrum). The study was carried out on the basis of the digital software package "Synergotron" with a controlled internal environment.Results. An increase in the share of UV-A in the illumination spectrum leads to a significant change in the biometric indicators of plants – the aboveground biomass increases by 2.2 times compared to the control, and the mass of the underground part (root crops), on the contrary, decreases by 86.9%. At the same time, the share of root crops in the total biomass of plants decreases from 60% in the control to 30%. The morphological structure of the leaf apparatus changes: the proportion of petioles increases significantly compared to leaf blades (64.8% of petioles in aboveground biomass, whereas in the control 30%). Probably, an increase in the share of UV-A in the spectrum can favorably affect the cultivation of leaf forms of beets and other root crops. UV-A radiation leads to a change in the chemical composition of root crops, in particular, a decrease in the accumulation of dry substances (by 1.58%) and a decrease in sugar content (by 1.8%). An increase in the proportion of UV-A in the irradiation spectrum changes the parameters of chlorophyll fluorescence and contributes to an increase in the maximum quantum yield of Fv/Fm, non-photosynthetic quenching of NPQ fluorescence and a decrease in the real quantum yield of photosynthesis Y(II), as well as the electron transport rate (ETR).