Potatoes contain antioxidants such as flavonoids, carotenoids and ascorbic acid. High level consumption worldwide makes potato a valuable source of phytonutrients. Developing new potato varieties with high nutritional value in combination with resistance to pathogens is an important task. In this study, 25 interspecific potato hybrids with resistance to Synchytrium endobioticum, common scab, silver scab, rhizoctonia, nematodes and PVY were evaluated for total phenolics, total flavonoids, total carotenoids, ascorbic acid contents and antioxidant activity. The identification of the dominant allele related with yellow flesh color at the Chy locus was also performed by the specific CAPS marker. Total protein content was detected and ranged from 8.19 ± 0.59 to 30.17 ± 4.56 mg/g dry weight (DW). Total starch and total carbohydrate contents were in the range of 9.0–21.0% and 73.21 ± 20.94–676.36 ± 195.28, respectively. Total phenolic content of hybrids varied from 8.45 to 82.75 mg/100 g, and total flavonoids content—from 0.64 to 9.67 mg/100 g DW. It is possible to distinguish samples with high protein and carbohydrate contents, high level of substances with antioxidant activity and characterized by resistance to pathogens. Quality evaluation has shown that some of the samples have a high potential for processing and chip production in combination with high eating qualities. These samples can be used in breeding programs to develope varieties resistant to pathogens and with high nutritional value.

Material for research was fresh leaves of Amaranthus tricolor L. varieties Early Splendor. They were grown in a greenhouse (Federal Scientific Vegetable Center, Moscow region). Using GC-MS, 8 and 11 amino acids were identified in extracts of hetero- and autotrophic leaves. One of the mechanisms that provide resistance to stresses of various natures is the accumulation of free amino acids; therefore, the total content of antioxidants can serve as an indicator of plant resistance. The amino acids found in amaranth leaves have pronounced functional activity in the human body. For example, tyrosine is the most important neurotransmitter, stimulates the brain, is involved in the control of stress. In humans, the precursor of tyrosine is the essential amino acid phenylalanine, while tyrosine is formed by hydroxylation of the phenyl group of phenylalanine. In this case, the lack of the latter in food leads to a deficiency of tyrosine in the body. Tryptophan controls the body's protective and adaptive functions. Amino acids valine, leucine, glutamine, proline - stimulate the growth of beneficial intestinal flora and biomass accumulation. Thus, the amino acid composition determines the nutritional and pharmacological value of amaranth leaf biomass. This indicates that amaranth leaves are a promising raw material for creating functional products and herbal remedies.

The potato cyst nematodes (PCN) Globodera rostochiensis and Globodera pallida are the most common pests feeding on potato roots. These pests have an aggressive distribution dynamic and bring a lot of damage to yield. The study presents results of comprehensively test new potato genotypes for resistance to the golden potato nematode (Globodera rostochiensis), for its further use in breeding and the creation of economically valuable resistant varieties. Almost half of the samples showed laboratory resistance to golden potato nematode, the rest were susceptible. 26 samples have shown the presence of two molecular markers (N146, N19), indicating the presence of H1 gene. Almost all samples showed a correspondence between laboratory resistance and the presence of H1 gene markers.