The big retail chains incur lot of losses of the fresh fruit and vegetable products, the considerable part of which formed by fresh imported tomatoes. This article presents the results of an experiment conducted at Federal State Budgetary Scientific Institution North Caucasian Regional Research Institute of Horticulture and Viticulture of city Krasnodar for the investigation of influence of temperature conditions on tomatoes quality of the “Torbash” sort during storage. As a biochemical parameters of the quality assessment were investigated acidity, dissolved dry matter content, ascorbic acid and sugars content. Correlation analysis of the data with a changing parameter “temperature” has revealed dependence of the vitamin C content on glucose and the total content of sugars 240 hours after storage. Analysis of data on vitamin C and glucose at a fixed factor “storage time” has showed a high correlation of these parameters at a temperature of 18°С, at 22°С the correlation is moderate. Moderate correlation of the vitamin С content with the sum of the sugars is observed at temperature of plus 16°С; at 4 and 18°C there is a weak correlation. But correlation analysis for sugars and acidity showed no correlation at temperatures other than normal (7…8°С). The ratios of vitamin С and glucose or vitamin С and the amount of sugars can serve as indicators in estimation fruit quality, and the weak of correlation between sugars and acidity at temperatures other than 8°С indicates storage of the product with temperature disturbances

Relevance. High temperatures are among the environmental factors that negatively affect the development of most crops including tomatoes. Thus, important condition for the realization of potential plant productivity is the heat resistance.Methods of the gamete selection in combination with classical approaches can be used to select resistant genotypes and create initial breeding material with resistance to the temperature factor. Materials and methods.The experiments were carried out with intraspecific hybrids F4 of tomato: Elvira x Milenium, Elvira x Tomis, Elvira x Prestij, Mihaela x Milenium, Mihaela x Tomis, Mihaela x Prestij, Jubiliar х Milenium, Jubiliar x Tomis, Jubiliar x Prestij, Milenium x Elvira, Milenium x  Mihaela. Plants were grown in the field. Flowers were collected, anthers were separated, pollen was isolated. Pollen was heated for 2 or 4 hours at 43°C in the experimental variants. In the control, pollen was maintained at a temperature of 26°C. Then pollen was sown and germinated on a cultural medium. The viability was determined by the length of pollen tubes.Results.A different reaction of pollen grains to temperature influence was established. The main sources of variability and their contribution to the variability of the pollen and seedling traits were determined. The temperature and genotype mainly determine the variability of the gametophyte and sporophyte. More than half of the hybrids combined high indicators of resistance of both pollen and seedlings, formed a larger number of flowers and better set fruits. Thus, tomato genotypes with good indicators of heat-resistance for applying in breeding have been identified based on a complex of methods for assessing the resistance of hybrids using gametophyte and sporophyte characteristics, as well as results of genetic-statistical analysis.

The priority direction in melon breeding is the creation of new competitively capable varieties that combine resistance to adverse environmental factors with valuable economic characteristics.Materials and methods. The object of the study is melon varieties 599 and 595. The purpose of this study is to study the influence of weather conditions on the yield and biochemical composition of the studied melon varieties in the conditions of the Volgograd Volga region. The research was carried out at the Bykovskaya melon breeding experimental station for three years according to the developed methods, the Osen variety was used as a standard.Results. The article presents the results of the influence of weather conditions on yield, fruit weight, and also presents an analysis of the biochemical composition of melon fruits. A complete description of the studied melon varieties is given. In terms of yield, the high indicators for cultivars 599 and 595 were in 2020 with the totals of average monthly active temperatures of 114°C and precipitation totals of 178 mm, and amounted to 19.0 t/ha and 21.3 t/ha. According to the content of dry matter in the fruit juice, according to the results of studies, it was seen that with the greatest amount of moisture, the indicators were higher in 2018 with a precipitation rate of 296 mm in cultivars 599 – 13.6%, in 595 – 13.2%, than in 2019 with a norm of 272.6 mm 599 – 12.0% in 595 – 11.6%. Thus, we can conclude that these melon varieties meet the modern requirements of the industrial melon industry.

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.

Relevance. Tomato root rot is a complex disease caused by a variety of soil-borne fungal pathogens, among which Fusarium oxysporum, F. solani and F. gibbosum occur with the greatest frequency in the conditions of the Republic of Moldova. The originality of the work consists in identifying the differentiated influence of pathogens of Fusarium root rot and temperature on the variability and heritability of the organs of growth and development of tomato plants.Material and methods. Two varieties and 3 lines of tomatoes with good economically valuable characteristics were used as material for the study. To test the response of plants to pathogens of fusarium root rot, we used culture filtrates of 6 – F. oxysporum isolates, 6 – F. solani, and 4 – F. gibbosum, prepared in a standard liquid Czapek medium. The plants were grown at the optimum temperature (23...24°C) and with alternating temperatures of 23...24°C and 10...11°C for two days each. Seed germination and root length were used as indicators of growth and development. The genetic parameters of the variability and heritability of the studied traits were studied.Results. An analysis of the reaction based on seeds germination and root growth showed its significant differentiation in the tomato genotype x type of fungus x isolate of the fungus x temperature system. A factor analysis of the interaction of the tomato genotype x Fusarium fungus revealed a significant role of the plant genotype in response to the pathogens. A significant effect of Fusarium fungi and temperature on the genetic and phenotypic variance of signs of growth and development of tomato plants, heritability in a broad sense, genotypic and phenotypic coefficient of variation, and genetic progress have been established. It is concluded that it is advisable to use the reaction of signs of growth and development of tomato to Fusarium pathogens in order to identify genotypes with good inheritance of the resistance trait.

The study of the dynamics of plant growth and yield of vegetable crops (carrot variety Absheron winter (Daucus carota subsp. sativus (Hoffm.) Schьbl.) and radish variety Virovsky white (Raphanus sativus var.radicula Pers.)) was conducted in the field conditions after presowing exposure to different temperatures: I option – sowing of seeds exposed to low temperatures (for 15 days the swollen for 24 hours seeds were kept at a temperature of 0±1°С); Option II - sowing of seeds exposed to variable temperatures (for 5 days, the swollen for 24 hours seeds were exposed to variable temperatures of + 20°C (8 hours) and 0±1°C (16 hours) and then 10 days at a temperature of 0±1°C; K1 – sowing dry seeds; K2 – sowing soaked seeds. The impact on the seeds of low and variable temperatures caused an increase in growth processes, both in radish and carrot. Both studied crops showed a tendency to increase the yield to a greater extent when exposed to swollen seeds with variable temperatures. Thus, the average weight of radish crops exceeded the control variant by 47.1% and carrots by 27.6%. The yield of root crops per m2 increased by 36.4% for radish and 30.0% for carrot. To increase the productivity of vegetable crops, we recommend using the studied methods of pre-sowing seed treatment in practice.

Based on the researches conducted in conditions of vertical zonality of the Chechen Republic, the high-yielding varieties of red beet in the certain climate and environmental conditions were selected. Moving from the plain zone to the piedmont and the mountain zones, the yield of red beet roots has increased by 1,6-3,4 t/ha regardless of early ripeness of cultivars and hybrids. Application of mathematical modeling allows the selection of the varieties, which are able to realize their yield potential in various conditions.

Relevance. In the Republic of Moldova in recent years, during tomato flowering, air temperature reaches 35°С and higher, which significantly reduces fruit set, yield and product quality, therefore, the creation of varieties resistant to temperature stress is of particular importance. The relevance of the studies is due to the need to identify tomato genotypes resistant to high temperatures, to identify the genetic nature of the variability and degree of inheritance of tomato growth organs when interacting with different temperature conditions. The purpose of the research is to determine the effect of stress temperatures on the organs of growth and development of tomato plants at an early stage of ontogenesis, the degree of genetic, phenotypic variation and inheritance of characters. Materials and methods. The research material was 5 promising lines of tomato with high economically valuable traits. As a standard, a omologated variety Mary Gratefully was used. Four temperature levels were used – optimal (25°С) and stress (38, 40 and 42°С). The length of the germinal root and stem of 7-day-old plants was measured. The experiment was made in 3 replicates. The following were studied: genetic and phenotypic variants, heritability coefficient, phenotypic and genotypic coefficients of variation, genetic progress. The data were processed in the STATISTICA 7 software package. Results. As a result of the studies, a significant differentiation of the reaction of tomato genotypes to temperature stress was revealed. A significant effect of temperature on the genetic and phenotypic varieties of signs of growth and development of tomato plants, heritability in the broad sense, genotypic and phenotypic coefficient of variation, and genetic progress have been established. Of a great interest for further studies are the Mary Gratefully, L 304, L 306 genotypes, which are highly resistant to the studied traits.

The application of phytogenous mulching materials based on local processed raw materials at potato cultivation in irrigated conditions of the Astrakhan region has allowed optimization of temperature and moisture regime of the soil. It was found that in case of the spring term of planting, the mulching has increased the soil temperature up to 0,6-0,9°C on April-May at a depth of 0,10 m as compared to the control. During heat period, mulching materials have decreased the soil temperature. Antecedent soil water under mulching materials in the phase of tubers formation was on 1,15-1,19 times higher than in the control variant without mulching. The most effective materials for the soils of different grain-size distribution were determined: for the heavy-loamy soil the best mulching material was straw, for the sandy loam soil the more efficient mulching was saw-dust.

The effect of temperature during seeds germination of some species of Umbelliferae vegetable crops has been studied. There is a different reaction of vegetable crops on the temperature factor: depending on crops and temperature, the number of days until the maximum rate of growth can varied from 7,6 to 22,8 days, and percentage of germinated seeds can varied from 7% to 88%. The effect of temperature on growth of seeds embryo has been studied in different crops. The «degree of underdevelopment of embryo» (DUE) characterized the morphological and anatomical features of embryo varied from 13 to 52%. The temperature coefficient (Q10) for the rate of germination of seeds of vegetable crops of Umbelliferae was 1,23 - 1,82.