Antioxidant properties, betalain profiles and biochemical composition were studied in table beets with maroon and yellow root colors. Features of dynamic changes during the growing season were described. Significant differences in antioxidant activity were found in table beet accessions with differently colored roots. Negative dynamics of antioxidant activity were observed in all accessions. Statistically significant differences were registered among the accessions in the total amounts of phenolic compounds, chlorophylls, and betalains. The group of maroon accessions demonstrated strong positive correlations between their antioxidant activity and total phenolics (r = 0.91), antioxidant activity and betacyanins (r = 0.80), and between betacyanins and phenolics (r = 0.90). The antioxidant activity in the accessions with yellow roots was associated with chlorophyll b (r = 0.85), ascorbic acid (r = 0.83), and total phenolics (r = 0.83). The data are presented on the structure of betalains in two table beet groups contrasting in their root color. The results of the study made it possible to identify key components in the biochemical profile of differently colored beetroots, associated with their high antioxidant activity. Dynamic changes were shown for the antioxidant activity and fractional composition of betalains in table beet during its growing season, and a conclusion was made concerning the higher nutritional value of maroon cultivars.

Table beet (Beta vulgaris L.) is a source of the natural red-colored food dye (E162), highly demanded for the broad spectrum of its biological activity. The relevance of this study is dictated by the lack of knowledge about the dynamics of changes in the crop’s betalain content during the growing season, which impedes identifying the optimal timing of harvesting in order to obtain the dye. This paper presents the results of research into betacyanins (BC) and betaxanthins (BX), separately in the peel and flesh of roots, in 15 differently colored table beet accessions from the collection of the N.I. Vavilov Institute (VIR). There was no statistically significant accumulation of betalains in beets during the growing season. The pigment’s significant fluctuations associated with abiotic environmental factors were shown. The ratio of BC/BX in red-colored accessions was measured: 2.65 in the peel and 2.9 in the flesh. Strong positive relationships were found between BC and BX in the peel (r = 0.97) and flesh (r = 0.79) of red-colored biotypes, which stably persisted throughout the growing season. The beetroot peel was more sensitive to temperature changes, in contrast to the flesh. The negative effect of a temperature increase on betalains in red-colored beetroots intensified on the second or third day. The pigment composition of the flesh was less susceptible to the negative impact of increased temperatures, but reacted negatively to rainfall, becoming more expressed on the second or third day. A conclusion was made about the morphotype with high betalain content. Recommended cultivars are mid-ripening, with rounded and medium-sized roots, a large number of narrow leaf blades, and short and thin petioles.

The table beet, a widespread edible root crop known for its medicinal and antioxidant properties, early maturation, good shelf-life, and high contents of bioactive compounds, vitamins and minerals, is used for the production of a natural red food dye (E 162). The relevance of this study is dictated by the lack of knowledge about the dynamic changes in the content of betanin during the growing season, when table beet cultivars are developed with a focus on pigment extraction. The article presents the results of a study a set of 29 red-colored table beet accessions from the collection of the N.I. Vavilov All-Russian Institute of Plant Genetic Resources (VIR). Dynamic changes in the content of the pigment during the growing season were observed on two beet accessions, cvs. ‘Russkaya odnosemyannaya’ and ‘Bordo odnosemyannaya’. Four pH versions of the buffer solution were tested, and the test results are presented. A buffer solution with a pH of 4.5 to 6.5 is recommended for research purposes. The amplitude of variability in the content of betanin in the peel (39.9 - 239.2 mg / 100 g) and flesh (14.4 - 127.5 mg / 100 g) of beets was determined. It was confirmed that the content of betanin in the peel in all samples exceeded that in the flesh. A positive relationship between these indicators was revealed (r = 0.74, p ≤ 0.05). A positive relationship was found between these indicators. It was found that betanin accumulation did not occur in beet roots during the growing season. The pigment showed considerable fluctuations associated with abiotic environmental factors. Correlation analysis showed a significant positive relationship between air temperature and betanin content in the root flesh (r = 0.32 – 0.31, p ≤ 0.05). A negative impact of environmental temperature on betanin content in the peel manifested itself on the third day (r = -0.34 – 0.35, p ≤ 0.05). The negative response to precipitation was less expressed in cv. ‘Bordo odnosemyannaya’ due to the genotype’s more active metabolism and plasticity. Structural morphological features of the photosynthetic apparatus were described for the tested accessions, and their interrelations with the studied character were specified. Recommendations are given concerning the choice of a planting pattern and the timing of table beet harvesting for pigment extraction.

Amaranthus cruentus L. and Amaranthus hypochondriacus L. are valuable and promising food crops for multi-purpose use that are distributed worldwide in temperate, subtropical, and tropical zones. However, their karyotypes and genomic relationships still remain insufficiently studied. For the first time, a comparative repeatome analysis of A. cruentus and A. hypochondriacus was performed based on the available NGS data; bioinformatic analyses using RepeatExplorer/TAREAN pipelines; and chromosome FISH mapping of 45S rDNA, 5S rDNA, and the most abundant satellite DNAs. In the repeatomes of these species, interspecific variations in the amount of Ty3/Gypsy and Ty1/Copia retroelements, DNA transposons, ribosomal, and satellite DNA were detected. In the repeatomes of both species, shared satDNAs with high sequence similarity were identified. The chromosome distribution patterns of four effective molecular markers, 45S rDNA, 5S rDNA, AmC4, and AmC9, allowed us to identify all chromosome pairs in the species karyotypes, construct unique karyograms of A. cruentus and A. hypochondriacus, and confirm the close relationship between their genomes. These results are important for comparative karyotypic studies within the genus Amaranthus. Our findings demonstrated that cytogenomic analyses might provide important data on genomic relationships within Amaranthus and increase knowledge on genome organization in these valuable crops.