Relevance. Pepper is sensitive to chilling temperatures in all growth stages and low temperatures are main factors affecting plant growth, fruit growth and development and productivity. Evaluation and identification low temperature (LT) tolerant pepper genotypes at different growth stages is actual in breeding program for developing new cultivars. In present study we investigated the effect of the leaf cold damage within 25% (LCD) after chilling treatment in seedling stage on vegetative and reproductive traits of pepper accessions with different cold tolerance.

Material and methods. In this study two pepper accessions “PE-J-2” and “Neokgwang” selected as chilling tolerant and susceptible in juvenile stage (3-4 true leaf stage), were used respectively. The seedlings of the selected pepper accessions with 25% visual cold damages of leaf green part (become lightly yellowed-whited or desiccated-dried) and control non-treated (NT) were grown in a glasshouse condition (D/N 30-32/22-24°C) for 10 weeks to evaluate the effect of LCD on pepper accessions vegetative and reproductive parameters after chilling pre-treatment. In pepper plants the vegetative parameters such as plant height (PH), leaf length (LL) and width (LW), number of internodes (NI), length of main axis (LMA), plants fresh weight (PFW) and roots fresh weight (RFW), and reproductive the number of flowers (NFL) and fruits (NFR), fruit set ratio (FS), fruit length (FL) and diameter (FD), total yield per plant (TY) were measured. The experimental design of this study was completely randomized. Statistical analysis was performed using the SAS Enterprise Guide 7.1 (SAS Institute Inc., Cary, North Carolina, USA).

Results. According to the research result several accessions were identified: the accessions screened in juvenile stage as cold tolerant cannot always manifest good some agronomical traits performance at growth stages and it may range depending on the genotype specific features. The seedlings with LCD within 25% may significantly affect the vegetative and reproductive parameters of pepper plants. The phenomenon was recorded more distinctive in the correlations between some vegetative and reproductive parameters among NT and LCD plants.

Turnip, Brassica rapa L. subsp. rapa is the oldest vegetable crop in Russia. Turnip varieties are fastgrowing, productive, have valuable biochemical properties, cold-resistant, relatively easy to grow. To expand the vegetable assortment, new varieties and hybrids should be created, first of all, the types of varieties that are not in the State Register of Russia. The purpose of the work: using the data of a long-term study of the VIR collection to identify valuable material for breeding.

Methods. Field study of 170 samples of the VIR collection was carried out in the NPB "Pushkin and Pavlovsk laboratories of VIR" (Leningrad region) in 2001-2020. Sowing was carried out on June 26- 28. Each sample was sown on a single-row plot 2 m long in three repetitions. As a control, turnip varieties included in the State Register were used – the variety of leaf turnip Sapphire, the table turnip variety Petrovskaya-1 and the fodder turnip variety Osterzundomsky. The description was carried out according to the Methodological Guidelines for the study and maintenance of the VIR world collection, with author's additions.

Results. The best leaf turnip samples, found during the study has a large plant mass (up to 1.42±0.32 kg in the Early top F1 sample (k-366, Japan), many samples exceeded the Sapphire standard for this trait. Some of the samples of table turnips also exceed the Petrovskaya-1 standard by weight of the root (Purple top (k-1345, Nepal), Pekki (vr.2176, Finland)). Samples Solovetskaya (k-803, Russia, Murmansk region), Gul Findlandsk (vr.2175, Norway) have a bright yellow flash of the root, are easy to store and resistant to damage by cabbage flies. Among the turnip samples distinguished by yield (Table 5), the most interesting are the turnips Ova Dæhnfeldt (vr.2183, Denmark) and Korova (vr.2187, Sweden), which have yellow flesh and an increased content of β-carotene in roots.

Conclusion. It was possible to identify new samples belonging to groups of leaf and root turnips, that are not represented on the seed and food market of Russia. Such samples belong to morphologically different forms, are productive, carry a complex of valuable economic and biochemical characteristics and are perspective material for inclusion in programs for the selection of leaf and root crops.

The purpose of the study. The aim of the study was to determine the effect of heterosis in short-fruited parthenocarpic F1 cucumber hybrids by the main economically valuable characteristics, when grown using low-volume technology in industrial greenhouses of the Moscow region.

Materials and methods. The object of the study is short-fruited parthenocarpic reciprocal hybrids of cucumber Druzhny (F₁ I₇3514 x I₇4011), F₁ I₇4011 x I₇3514 and their parent inbred lines I₇3514 and I₇4011 of selection by N.N. Timofeev Breeding Station LLC. F₁ SV4097CV of foreign selection of Semenis company (Netherlands) was used as a control. The study was conducted in 2020-2021 in industrial greenhouses of the "V. I. Edelstein Vegetable Experimental Station" of the K.A. Timiryazev Russian State Agrarian University-Moscow Agricultural Academy in Moscow on low-volume hydroponics in peat bags. Parental lines and hybrid combinations were evaluated by earliness, early yield, yield, number of fruits per plant, average fruit weight and marketability.

Results. According to the results of the study, F₁ Druzhny (F₁ I₇3514 x I₇4011) and the reverse hybrid I₇3514 x I₇4011 demonstrated high positive effects of heterosis in yield (MPH=19.4...22%; HPH=13.4...15.9%; CH=9.6...12%) and the number of fruits per plant (MPH=22.5...26.4%; HPH=12.5...15.8%; CH=11.7...15%). Negative indicators of the heterosis effect were noted for earliness from germination to flowering (MPH=-3.4...-1.1%; HPH=-6.5...-4.4%; CH=-4.4...-2.2%) and average fruit weight (MPH=-2.2...-1.3%; HPH=-5.3...-4.3%; CH=-3.4...-2.4%). The value of the degree of dominance indicates the presence of positive overdominance in the inheritance of such traits as yield (hp=2.7...3.2), the number of fruits from the plant (hp=1.5...1.9) and marketability (hp=1.6...2.3). Negative overdomination was observed in earliness from germination to flowering (hp= -2...-1.3) and average fruit weight (hp=-1.7...-1.2). According to the signs of earliness from germination to fruiting (hp =0) and early yield (hp=-0.1...0.5), intermediate inheritance was revealed. The Druzhny hybrid significantly exceeded the control hybrid SV4097CV in early yield, yield and number of fruits from the plant, and the reverse hybrid F₁ I₇4011 x I₇3514 was at the control level, which indicates the prospects of growing these hybrids in the conditions of spring-summer turnover on low-volume hydroponics.

Relevance. Obtaining modern cucumber hybrids is impossible without the constant involvement of genetically new sources in the breeding process. One of the most important tasks in the issue of creating new heterotic cucumber hybrids is to obtain, and in the future, selection for hybrid crossings, parental lines with the most important economically valuable traits. Research is aimed at obtaining new short-fruited cucumber lines with a smooth type of fruit in order to obtain hybrids with their help that combine resistance to powdery mildew for the “pm” and “pmh” genes, tolerance to the zucchini yellow mosaic virus for the “zymv” genes in combined with high yields, the possibility of growing them not only in unheated film greenhouses, but also in glazed greenhouses.

Methods. This article presents two schemes for obtaining parental forms using the example of creating four cucumber lines with a short, smooth fruit. Their comparative characteristics and description of new hybrids created with the participation of the studied linear material are carried out. Materials and methods. The main studies were carried out in 2013-2020 on the basis of the Pumpkin Cultures Laboratory of the Krymsk Breeding Center "Gavrish" of the Research Institute of Vegetable Breeding (Krymsk, Krasnodar Territory). The research material is F1 hybrids and selection samples of parthenocarpic cucumber with a smooth type of fruit of various origins (34 samples in total) from the NIISOK collection. The work used traditional methods for assessing selection-significant traits and modern methods of molecular labeling. The purpose of the work is to compare two schemes for obtaining short-fruited cucumber forms, to evaluate the created lines and hybrid combinations with their participation in terms of a complex of economically valuable traits.

Results. The result of the work was the creation of new hybrid combinations based on the obtained lines, two of which are included in the State Register of Breeding Achievements. These are F1 Ministar (F1 1600/16) and F1 Promini (F1 1995/16).

Seven accessions of vegetable fennel selection of the Federal Scientific Vegetable Center for Ecology were studied, in which significant differences were found in the degree of expression of the main morphological parameters (the length of the seed, endosperm and embryo). The length of each seed, endosperm (on a longitudinal section), and embryo (after isolation) were analyzed sequentially. The experiment was repeated four times, in each repetition at least 30 seeds. The indices IE/S, IZ/E, IZ/S were calculated as the corresponding ratios of the length of the seed, endosperm, and embryo.

Results. A group of vegetable fennel samples showed significant differences in the length of the seed, endosperm and embryo and their ratios. The variety Udalets used as a standard had a seed length of 6.85±0.164 mm, an endosperm length of 5.30±0.118 mm, and an embryo length of 2.35±0.093 mm. Population No. 17 of the FSVC and variety Corvette of the VNIIO selection and collection sample vr. 161 local populations from India significantly (by 18.5 and 17.5%) exceeded the average value of the standard for seed length at a 1% significance level, and the minimum value of the parameter (5.65±0.109) was noted in population No. 10 of the FSVC. The minimum endosperm length was noted in samples No. 10 (4.16±0.094) and No. 11 (5.11±0.167), which is 21.5 and 4.5% lower than the standard. The largest endosperm was possessed by the seeds of the Korvet variety (6.18±0.169 mm) and sample No. 17 of the FSVC (6.09±0.158 mm), which exceeds the standard by 16.6 and 14.9%. The remaining samples exceeded the standard in this indicator, but to a lesser extent. The length of the embryo only in the Corvette variety (2.38±0.097 mm) was at the level of the standard, and even slightly exceeded it. For the rest of the specimens, this indicator varied from 1.44±0.065 mm for No. 10 to 2.25±0.165 mm for No. 10, which is significantly 4.2–38.7 below the standard. Depending on the sample, the coefficient of variation of indicators changed for the length of the embryo (17.7-32.8%), the length of the endosperm (9.6-12.2%) and the length of the seed (8.6-12.8%). A close relationship was noted only between the length of the seed and the length of the endosperm, the correlation coefficient varied from 0.595 (No. 11 FSVC) to 0.837 (Udalets St). All values of the correlation coefficient had a positive value. According to the value of the Ie/z index, the seeds of accessions No. 15 of the FSVC and vr. 161 India. Seeds of accessions No. 17, No. 10 and varieties Corvette with an index from 0.30 to 0.39 are assigned to the third class. The fourth class includes seeds of the variety Udalets (St) and selection sample No. 11 of the FSVC.

Relevance. As a result of long-term research, the staff of the Department of Agronomy, Plant Breeding and Seed Production of Omsk State Agrarian University created a new variety of green beans called Marusya, which was included in the State Register of Breeding Achievements in 2015. The competitiveness of the variety is ensured by stable yields, high palatability, and the ability of green beans to maintain their economic viability over the long period. The variety is resistant to drought and low temperatures.

Material and methods. The research on the variety of the green beans was conducted following the methods of competitive variety trial from 2016 to 2020. The trials were conducted on the breeding crop rotation fields of the Educational and Experimental Farm of Omsk State Agrarian University, which is located in the southern forest-steppe of the Omsk Region (city of Omsk). The following zoned varieties were used as control samples: Zolushka (Federal Scientific Center of Vegetable Farming, Moscow) and the imported Polka variety (Poland).

Results. The developed agroecological passport the Marusya variety, the use of which will allow to take into account the positive effects of the genotype-environment-variety interaction to the maximum extent. When selecting bean varieties suitable for cultivation for vegetable purposes in the conditions of the southern forest-steppe of Western Siberia in industrial production and the private sector, the Marusya variety makes it possible to obtain high-quality products and expand the range of legumes in the region.

Relevance. Tomato is one of the main vegetable crops and is grown everywhere in the open and protected ground in the North Caucasus region of Russia. Therefore, increasing the production of tomato fruits in the open ground is an important task for vegetable growers in the south of our country. There is too much dependence on imported seeds. To get rid of this, it is necessary to increase breeding activity, create domestic varieties and hybrids of tomatoes with high potential productivity, resistant to adverse environmental factors and adapted to local growing conditions.

Methods. The research was carried out at the experimental site of the Federal Agrarian Scientific Center of the Republic of Dagestan, located in the Primorsky lowland, at an altitude of 17 m above sea level. Agrotechnics is generally accepted in the Republic of Dagestan for tomato culture.

Results. The results of the research indicate that most of the studied varieties and hybrids belong to plants of the determinant type of early maturation with average stability, with large and medium fruits of flat-rounded and rounded shape, with medium and high yields and relative resistance to fungal diseases. According to the largest number of fruits on the first brush, four varieties differ: Topaz, Yana, Chelnok, Talisman (6.5-5.7). On the basis of the "number of fruits" on the second brush, almost all varieties are marked, which is of interest to breeding. On the basis of the "distance between the brushes" varieties Yana, Marti, Grant, Perst, Topaz – are characterized by a generative (shortened internodes) type of plant (12-16 cm). The source material also differs in the shape of the fruit – 8 samples have a rounded, 3 samples have an elongated oval, 5 samples have a flatrounded and 2 samples have a cuboid shape of the fruit. The color of the fruits in the technical phase of ripeness in the studied varieties and lines was with (8 samples) or without (12 samples) an intense green spot. In biological ripeness 12 varieties and lines have a red color of the fruit.

Relevance. The actual demand for cabbage is based on the demographic composition of the Russian population. Based on this provision, the weight size of marketable, in particular, midripening cabbage, in the range from 1 to 3 kg, is justified. However, until now, domestic breeding firms are focused on the creation of hybrids with increased yields, not taking into account the real demand of the population.

Materials and methods. The studies were carried out on mid-season hybrids of white cabbage of the fifth maturation group SB-3 F₁ and Kuizor F1 in vegetable-growing farms of the NonChernozem zone of the Russian Federation typical for that time: "Bykovo" and "Agrofirma" Podmoskovnoe".

Results. Studies on the mid-season hybrid SB-3 F₁ showed that the share of commercial heads of cabbage ranged from 32.9-44.1%, reaching 73.3% in only one technological variant. The share of commercial heads in hybrids of foreign selection Kuizor F₁ was 97%. A radical way to meet the requirements of the population is the creation of mid-season hybrids with different dynamics of growth of the marketable mass of heads of cabbage and, accordingly, with different lengths of the growing season. This is necessary to ensure the receipt and sale of marketable products – biologically ripe heads of cabbage weighing 1-3 kg within 2-3 months of the summer-autumn period. At the same time, obtaining such heads of cabbage should be ensured by the genetic potential of hybrids.

Relevance. Onion is a valuable food crop, which is due to its chemical composition, taste and medicinal qualities. As part of the strategy to ensure food security and independence of Russia in the agricultural sector, it is necessary to increase the production of vegetable products, including onions, and for this it is necessary to increase the production of domestic seeds. Seed production is an important branch of agriculture, which consists in the planned reproduction of zoned varieties. Unlike commodity production, it is a more labor-intensive industry and requires regular improvement of existing technologies that take into account the specifics of new varieties and hybrids.

Materials and methods. The object is onion (Allium сера L.). Research material: new varieties of spring onion Primo and Ampex of selection of FSBSI FSVC. The studies were conducted in 2018-2020 on the basis of the North Caucasus branch of the FSBSI FSVC. Laboratory and field experiments were carried out according to generally accepted methods. The area of the accounting plot is 5m² , the repetition is 4-fold, with a randomized arrangement of options.

Results and discussions. Different planting dates of uterine bulbs, their diameter, standing density, planting depth, significantly affected the qualitative and quantitative indicators of seed productivity of onion plants of Primo and Ampex varieties. The results obtained made it possible to modify and optimize individual elements of varietal technologies of onion seed production. To create the best conditions for the growth and development of seed plants of Ampex and Primo varieties and to obtain high yields of high-quality seeds in the conditions of the foothill zone of the North Caucasus, it is recommended to: use queen bulbs of 8 cm in size, organize the planting of queen bulbs in the first decade of November, use a scheme for planting queen onions: 75x10 cm, use a planting depth of 15 cm. With this technology, the productivity of plant seeds reaches 6-8 g in the Ampex variety and 5-7 g in the Primo variety, and the yield of conditioned seeds is 520-580 kg/ha and 450-600 kg/ha, respectively.

Relevance. To increase the consumption of tomato and its diversity on the market, it is important to create new varieties that have economically valuable characteristics and are in demand among consumers. The aim of the research was to create a new determinant early-ripening variety of lettuce tomato, plastic, consistently productive, large-fruited, with dense pulp and high taste, tolerant to diseases.

Materials and methods. The studies were carried out at the collection site of the Crimean OSS of the VIR branch (Krasnodar Region, Krymsk). The Agata Plus cultivar was obtained by crossing parental forms with subsequent multiple selections against a natural infectious background. As a mother, we used a salad variety of the Russian selection Agata – early maturing, undersized, with an average yield and fruits with good taste and average weight. The paternal form was a hybrid of the Dutch selection F₁ Eploz, characterized by early maturity, medium height, medium leafiness, largefruited, dense pulp, consistently high yield and excellent taste of the fruit. The Agata tomato variety included in the State Register of the Russian Federation was taken as a standard.

Results. Evaluation of breeding lines for a complex of biological, morphometric, economically valuable traits using individual and mass selections made it possible to obtain the best early ripening form of salad designation, marked by large fruit size, consistently high yield and good taste. In 2017, this form, called Agata Plus, was submitted to the State Variety Test, and since 2020 this variety has been approved for use.

Relevance. In the central zone of the Krasnodar Territory, the mobility and availability of the main elements of mineral nutrition can be limited in certain phases of the growing season of melons and gourds, especially with a decrease in soil moisture and high temperatures. An important additional and corrective element of nutritional technology is foliar feeding, which increase the absorption of fertilizers during critical periods of plant growth and development.

Material and methods. The purpose of the research is to determine the effectiveness of foliar application with organic fertilizer AGROCHELATE to maximize the biological potential of watermelon varieties on seed plots during summer sowing. The research was carried out at the seed-growing area of the vegetable growing department in the "Federal Scientific Rice Centre" in 2020-2021. The object of research was selected varieties of watermelon selection “Federal Scientific Rice Centre” Tersky early and Yubilyar with a growing season of 65-75 days. Organic fertilizer AGROCHELATE was used to treat the leaf surface of plants with a consumption rate of 100 ml/ha. A single spraying was used during the flowering phase of the plants. For the isolation of seeds, fruits were selected that were characteristic of the varietal phenotype in the phase of biological ripeness: in shape, size, color and pattern of the bark, color of the pulp, size and color of seeds.

Results. In the Terskiy early variety, during spring sowing, fruits weighing 3.5-4.0 kg are formed. With summer sowing, the weight of fruits was significantly inferior and did not exceed 2.36 kg. The size of the Yubilyar watermelon fruit corresponded to the declared varietal parameters. The use of foliar application with organic fertilizer AGROCHELATE during the flowering phase did not affect the fruit weight. Analysis of the results of the content of dry soluble substances (DRS) in the pulp of the fruits showed a positive varietal response to the use of feeding. The share of influence on the improvement of the pulp quality indicator was 64.1%. On seed plots, after application of fertilizing with organic fertilizer AGROCHELATE, 0.81-3.09 t more than from control plots, selected fruits corresponding to varietal characteristics. The seed yield is largely influenced by the number of fruits selected for seed isolation. A one-time application of sheet processing made it possible to select a larger number of fruits on the Tersky Early variety - by 289 pieces./ha, on the Yubilyar variety – by 495 pcs./ha. Treatment of plants with organic fertilizer AGROCHELATE in the flowering phase contributed to an increase in the number of seeds in each fruit in the Tersky early watermelon by 19-127 pieces, in the Yubilyar variety by 9-111 pieces, respectively. Unripe seeds in fruits by varieties were 0.9-5.0% less than in untreated plants. In general, watermelon seeds obtained during summer sowing, regardless of the use of agricultural practices, corresponded to the elite category that can be used to grow marketable products.

Relevance. Currently pharmaceutical industry, food industry and chemical laboratories demonstrate an increasing interest in natural plant sources, including Chamaenerion angustifolium. Modern researches reveal more and more medicinal properties of this plant. For this reason, the demand for the use of fireweed as a medicinal plant, especially its leaves and flowers, is very high. It means, that the study of biological properties, chemical composition, ecological and landscape features of fireweed is of scientific and practical interest.

Methods. This article contains information from literary sources about pharmaceutical, chemical, biological, ecological and geographical studies of Chamaenerion, its results and recommendations. Obtained from other researches information was systematized by research topics and presented in a logical sequence.

Results. The issues of using this plant in medicine and food industry are also considered here, along with the discription of collecting natural fireweed problems and the mail ways of cultivating this species. The modern condition of fireweed research is shown, a detailed analysis of fireweed biological and ecological characteristics is carried out and on this basis, the main directions for further work on the introduction of Chamaenerion into culture for its more complete and rational use in medicine and in the food industry are outlined in this article. The article presents an analysis of the problems that arise during the introduction, in particular, the improvement of vegetative reproduction techniques, the selection of populations promising in terms of the phenolic compounds content and the possibility of target compounds content in plants by the exogenous regulation.

Conclusion. Despite the presence of a relatively large quantity of works devoted to Chamaenerion, some research topics are poorly covered. For example, the topic of cultivation and the use of growth regulators. The most promising directions for the future study of Chamaenerion are indicated in this article.

Scientific relevance. Plant viruses cause a significant economic loss to potato production, especially if plants are infected at early growth stages and infections are mixed. Viral diseases reduce both yield and quality of harvested crops. Detection and identification of plant viruses are key important to prevent their spreading and to achieve potential yield predetermined by characteristics of varieties.

Research methods. Seven potato varieties, bred in Russia and overseas, were used in the field experiment: Smak, Avgustin, Yantar, Laperla, Labella, Red Lady, Sante, Belmonda. Viral infection rate was measured by the percent of plants with symptoms to the total number of plants. In addition to infection frequency, a disease rate was described after visual estimation. Total RNA was isolated from the collected leaves according to Bekesiova I. et al. 1999 [13]. Qualitative and quantitative estimation of plant viruses in the samples were conducted by single-step real-time RT-PCR with fluorescent detection with the Applied Biosystems QuantStudio 5 and commercial kits “Potato Virus X, Y, M, L, S, A, PSTVd-RT” (Syntol Company) according to the official protocol of the kits.

Results. As a result of our research, symptoms of mixed viral infection were described for potato varieties depending on concentrations and proportions of these viruses in a plant. Mixed viral infection in the potato field in Primorsky Krai comprised PVY, PVX, PVA, PVS, PVM, also PLRV and PSTVd.

Relevance. The adaptive-integrated plant protection system is the basis of biologized protective measures against harmful organisms. This system provides for careful treatment of natural resources, prevents contamination of soil and water with pesticides and agrochemicals. In recent years, legislation and sanitary regulations have increasingly tightened the regulations governing the use of pesticides in crop production. Organic farming is becoming increasingly common. Leading global chemical companies are expanding their research on the biology of manufactured plant protection products: they give them a selective character, reduce the period of their inactivation, respectively, the waiting period. FMC manufactures and supplies to Russia new generation insecticides Verimark^® and Benevia^® from the chemical class of diamides compatible with the biomethode and having a short waiting time.

Methods. In 2020-2021, in the greenhouse complex of the FSVC, an assessment of the biological effectiveness of the insecticides Verimark^® and Benevia^® on cucumber culture has been carried out. Verimark^® was applied by shedding seedlings under the root and applying through a drip system, Benevia^® was introduced by ground spraying of vegetating plants.

Results. The most problematic cucumber pests in greenhouse are tobacco trips (Thrips tabaci) and greenhouse whitefly (Trialeurodes vaporarium). As a result of successive additions of the Verimark^® (for the root) and Benevia^® (for the leaves), the number of tobacco thrips was reduced by 90,8-98,9%. Spraying the plants with Benevia^® in admixture with Codacide oil also provided a high positive effect against the greenhouse whitefly. Already on the third day, the number of pests decreased by 90,3%. Protective measures made it possible to increase crop yield by 26.3% in the first turnover and 28.3% in the second. The highest rates of biological efficacy were observed in the use of preparations before the start of pest settlement, which is fully supported by the recommendations of the manufacturer.

Relevance. Potatoes belong to crops that place high demands on the level of mineral nutrition. He needs nitrogen especially badly. Timely introduction of calculated doses of nitrogen fertilizers based on the results of photometric diagnostics of plants allows rational use of fertilizers and increase potato yields.

Material and methods. The studies were carried out in the conditions of the Central region of the Non-Chernozem zone on sod-podzolic medium loamy soils with a high content of mobile forms of phosphorus and potassium and a low humus content (1,9%). The object of research is an early-ripening potato variety Bullfinch. To recalculate the dose of nitrogen fertilizing, photometric diagnostics of crops was carried out with an optical sensor GreenSeeker RT200. Additionally, before and after fertilizing, a manual N-tester Yara was examined. Before the main harvest, a control digging of tubers was carried out to determine the structure of the crop with division into 4 fractions.

Results. It was found that the introduction of nitrogen fertilizers into the top dressing during the closing phase of the tops in the form of ammonium nitrate has a generally favorable effect on the growth and development of potatoes. This is confirmed by the results of photometric diagnostics performed by the Yara N-tester during the withering phase of the tops. When applying top dressing with a fixed dose, the N-tester readings were 21,7% higher than in the control, and when applying fertilizers with a differentiated dose by 25,6%. The yield of potato tubers increased when applying a fixed dose of top dressing by 10,8%, differentiated by 14,5% compared to the control.