Relevance. Abiotic stress, as heat, significantly affect plant and floral organs growth and development, fruit set, productivity, the quality, and survival of crops. Heat injury occurs when plants are exposed to these temperatures for a long period of time. Depending on the intensity and duration of exposure to the high temperatures, photosynthesis, respiration, membrane integrity, water relations and the hormone balance of the plants may affected.Material and methods. In this study used the commercial pepper cultivar “NW Bigarim” (HT37) released in South Korea and accessions “Kobra” (HT1) and “Samchukjaere” (HT7) selected as heat tolerant and susceptible, respectively. Total chlorophyll index and photosynthetic activities measured using a SPAD meter (Konica, Japan) and portable photosynthesis measurement system (LI-6400, LI-COR Bioscience, Lincoln, NE, USA), respectively.Results. To evaluate the positive effects of high temperature regime (40/28°C day/night, 14/10-h light/dark cycle) on the response of photosynthetic parameters in pepper plants with different heat susceptibility, we measured the total chlorophyll content (CHL) and photosynthetic activities such as photosynthesis (Pn), stomatal conductance to H2O (Gs) and transpiration rate (Tr) in a heat-tolerant (HT1) and -susceptible cultivars (HT7) in comparison with released cultivar (HT37) at fruit development stage. Heat-tolerant cultivars showed higher and more stable index of the CHL, Pn, Gs and Tr than those in heat-sensitive cultivars for 14 days of heat treatment (HT) period. However, the initial index of Pn, Gs and Tr showed significant alteration among pepper plants regardless of thermotolerance rate before HT on day 0 and day 7 after recovery at normal treatment condition (NT) except for CHL, meaning that plants response to high temperature regime is different from that in normal condition. These results suggest that constant high rates of Pn, Gs and Tr as well as of CHL in heat stress condition periods confer to avoid from heat injury during reproductive growth stages.

Relevance. The success of breeding work is largely determined by the source material, the search and creation of which for target breeding begins with the collection and study of collectible samples for the alignment of morphological features; for the precocity and amity of maturation; for the keeping quality and transportability of bulbs; for the quality of vegetable products (high content of biologically active substances and antioxidants); for resistance to biotic and abiotic stressors of a specific growing zone.Materials and methods. On the basis of the North Caucasus branch FSBSI FSVC, 90 samples of spring onions from 26 countries of the world were evaluated in the number nursery for the period from 2017 to 2019, 71 of them were varieties and 19 were F1 hybrids. In a hybrid nursery, 25 hybrid combinations obtained from FSBSI FSVC (VNIISSOK) were evaluated. The laying and placement of experiments, agricultural techniques of cultivation, accounting and evaluation of economically valuable traits, biochemical analyses were carried out according to generally accepted methods. The standards are the new Primo and Ampex varieties of the selection of the FSBSI FSVC and the Italian F1 hybrid Ranko, which were placed every 10 collection samples.Results.According to the results of the assessment, among the studied F1 varieties and hybrids, sources of economically valuable traits such as yield (20-27 t/ha), precocity (80-90 days), preservation (more than 85%) when laid for long-term storage up to 7 months, purple, white and pink color of bulbs, as well as sources of long-shaped bulbs were identified. The greatest interest for breeding for yield is represented by 9 promising varieties and 9 F1 hybrids of onions of various origins, as well as 4 hybrid combinations that were distinguished by high yields, the yield of marketable products and the mass of marketable bulbs. These samples are recommended for use in the breeding process as sources for the creation of new varieties and hybrids with high yields for the agro-climatic conditions of the foothill zone of the North Caucasus.r breeding

Relevance. The modern marrow seed market shows the prospect of creating F1 hybrids that have the maximum return on a high-quality crop. For their successful selection, parental forms with a complex of economically valuable traits and a high combinational ability are required. The most important role is played by the female zucchini maternal lines of flowering type, which allow for hybrid seed production with free pollination and obtain high quality F1 hybrid seeds.Materials and methods. The studies were carried out at of the Krymsk EBS VIR Branch (Russia, Krasnodar Region, Krymsk) in 2019-2021. Variety testing of lines and hybrids was carried out in the open field in the fields of selective crop rotation. The plot area was 5 m2, the experiment was repeated three times.Results. The general combinative ability of parental squash lines was studied, maternal forms with a positive GCA effect on early yield (F5 409-1, F5 409-2) and on total yield (F5 409-1) were identified. A preliminary variety testing of hybrid combinations was carried out in comparison with the standards F1 Belogor and F1 Pascal. The main economically valuable traits have been studied: early maturity, early and general yield, marketability, product attractiveness. F1 hybrids of zucchini were identified, obtained on the basis of maternal forms of the female type of flowering F5 409-1, F5 409-2 in terms of yield (early above 17,7 t/ha and total above 46,7 t/ha), and marketability, more than 83,2%.Conclusions. The high productivity of F1 zucchini hybrids obtained on the basis of maternal forms of the female flowering type F5 409-1, F5 409-2 proves the promising nature of their use in breeding. As a result of two years of study, a hybrid F1 (409-1×305) was isolated, with a complex of economically valuable traits: early yield 19,6 t/ha, total yield 52,6 t/ha, marketability 84,3%, attractive appearance of fruits.

The saving and investment pattern of different forms sample group was studied during 2014-16 and it was observed that large farm holders were able to save higher income than small farmers while lowest income group had negative savings. In respect of investment on different fixed assets, irrigation was on first priority, followed by purchase of milch animals, farms buildings and investment in land and its improvement. Investment on working capital amongst different cash inputs, hired human labourer accounted highest share (29.44 per cent), followed by manure & fertilizers (22.33 per cent), hired power tractor (16.96 per cent), irrigation (13.61 per cent) and seeds (13.50 per cent) to total cash inputs. Marginal farmers could not invest for nonfarm physical capital because of no savings with them. Small and large farmers groups invested in all the items in which it was highest in working capital (61.28 to 61.84 per cent), followed by investment in fixed capital (14.41 to 16.84 per cent), financial capital (12-14 per cent) and non-farm capital (7-12 per cent). The highest investment was made on working capital (69.02 per cent) by sample farmers. Current income was found to be the main source of finance in all income groups which accounted for 49.70 to 94.79 per cent share of the total investment followed by savings which shared for 40.10 to 49.12 per cent in total investment.

Relevance. The presented studies are aimed at obtaining new forms of tomato with a complex of genes for resistance to fungal diseases in combination with a standard type of bush and dark coloring of fruits based on marker-mediated selection.Methodology. The biological objects of the study are varieties and hybrid forms of tomato from the collection of the Michurinsky SAU. Molecular genetic analysis was performed using the following methods. DNA extraction was carried out from young leaves using a kit for isolation of NC Sample NC manufactured by Agrodiagnostika LLC according to the manufacturer's protocol. Fermentas production kits were used for PCR. Identification of the cladosporosis resistance gene was Cf-19 performed using the DNA marker R7. The presence of a fusarious wilting resistance gene was determined by a I-2/5 marker. The amplification results were visualized by agarose gel electrophoresis.Results. During the research, a collection of varieties and hybrid forms of tomato of the Michurinsky GAU was analyzed in order to identify genes for resistance to cladosporiosis Cf-19 and fusarium wilt I-2. A total of 52 genotypes were analyzed. It was found that most samples (41 samples) are characterized by a heterozygous state of the Cf-19 gene. All indeterminant and semi-determinant forms had both alleles. Of the 23 determinant forms presented in the collection, 10 had only one allele corresponding to recessive homozygote. Among all analyzed tomato genotypes, no dominant homozygous forms were noted. The study of the collection revealed several alleles of the I-2 gene. In total, four fragments corresponding to various alleles were amplified. A total of 50 resistant genotypes have been identified in the collection. Two alleys of the I-2 gene (633/693 bp) were identified in 42 tomato samples. Four varieties are homozygous in one allele (633 bp), which determines resistance. Three varieties have a second resistance allele (566 bp). One genotype has only an allele defining susceptibility (693 bp). On the basis of molecular analysis, as well as an assessment of the type of bush and fetal color, initial forms were selected with subsequent hybridization. 67 hybrid tomato plants were obtained. Evaluation of the presence of resistance genes showed that most of the resulting hybrids are resistant to cladosporiosis and fuzariosis. This is due to the presence of dominant alleles of Cf-19 and I-2 genes in a heterozygous state. Among the resulting hybrids, plants with a bark type of bush were identified. A total of 13 such plants were obtained.Conclusion. Thus, the work carried out allowed to obtain hybrid forms of tomato combine the signs of resistance to two pathogens of fungal diseases and the stem type of the bush. These forms are planned to be used in further selection work.

Relevance. When growing cucumbers in a greenhouse not equipped with additional lighting, especially in winter, there is a shortage of solar energy. To obtain high yields of cucumber at this time, it is necessary to select the most resistant to low light hybrids. The selection of genotypes resistant to this trait is a very important stage in the selection of cucumber for winter-spring turnover.The purpose of the study: search for an easy-to-use method for early diagnosis of cucumber resistance to insufficient illumination.Methods. The research was carried out at the variety testing site in the Gavrish Breeding Center (Krymsk city) of the Scientific Research Institute of Vegetable Crop Breeding, in winter-spring turnover conditions, in greenhouses not equipped with artificial lighting. Seedlings were planted in a permanent place in the greenhouse during the period of the lowest arrival of solar radiation in the year on December 21. The measurement of the height of the main stem was carried out on 31 days after planting the plants in a permanent place.Results. Measuring the height of the main stem before fruiting showed a significant variation of this trait in different cucumber hybrids. Further study of the correlation of the height of the main stem and yield revealed their high dependence. This fact suggests that a fairly simple measurable parameter has been found for evaluating different cucumber genotypes on the basis of resistance to low light. Regression analysis made it possible to divide the variability of the studied genotypes by yield into a dependent part of the height of the main stem and an additional one, which makes up to 30% of the yield increase. Further analysis of the high-yielding group has a high breeding value.

Relevance. Currently, food products that include prebiotics, in particular, inulin, are particularly popular. Interest in this substance is justified by its valuable properties – it is a good immunomodulator, cleanses the body of toxins, radionuclides, "bad" cholesterol, promotes the assimilation of useful trace elements necessary for human life. Inulin is contained in plants such as jerusalem artichoke, chicory, as well as in sweet potatoes, the popularity of which is increasing every year. However, sweet potato plants are afraid of cold and frost-resistant. Therefore, the creation of new varieties and hybrids that are resistant to low temperatures is an urgent problem. Cellular biotechnology is aimed at solving this problem using methods of clonal microreproduction, cell selection, somatic hybridization, etc. For rapid reproduction and obtaining high-quality planting material, biotechnology methods are used, in particular, clonal micro-propagation. However, in this technology there are difficulties associated with poor adaptation of microclones to ex vitro conditions. This fact introduces an additional requirement for the selection of optimal rooting modes in vitro and ex vitro adaptation of microclones.Material and methodology. The aim of the work was to study the influence of cultivation conditions on in vitro rooting and ex vitro adaptation of I. batatas (L.) microclones. The object of the study was sweet potato microgears propagated in vitro. I. batatas micro-gears were cultured in vitro on a Murashige-Skug medium, differing by the type of auxins. The influence of red (R) and far red (FR) light on the shoots rooting in vitro and the adaptation of microclones ex vitro was studied.Results. It has been experimentally established that the cultivation of micro-gears on a medium containing indolyl butyric acid at a concentration of 0.5-1 mg/l and under conditions of illumination by LED lamps of red and far red light in equal amounts leads to the production of microclones with a well-developed root system and vegetative biomass. The use of an aeroponic installation at the last stage of clonal micro-propagation makes it possible to obtain high-quality planting material that can adapt well to open ground conditions.

The tomato culture is the leader in terms of cultivation area and production volume among food products of plant origin. Fruits contain a variety of minerals, sugars, fats, vitamins.The goal of the study and study of economic characteristics: yield, marketability, average weight of fruits, weight of 1000 pieces. seeds and seed productivity of tomato varieties of two varieties, created by Astrakhan breeders and the use of the results obtained in planning seed production and the development of sale and purchase prices for varietal seeds to provide large farms, summer residents and owners of private farms with domestic seeds for the purpose of import substitution and suitable for various uses.Methods. The experiments were carried out in the fields of Precaspian agrarian federal scientific center of the Russian academy of sciences according to well-known methods. Studied 9 salad and 7 for mechanized harvesting varieties of tomato.Results. The article presents the results of studying the economic qualities and seed productivity of tomato varieties of two types, differing in shape, size, weight, fruit color and directions of use. The first group includes large-fruited salad varieties with non-cracking fruits, which are well stored and transported in brown maturity with an average fruit weight of 100-200 g or more. The second group – with plumshaped and elongated fruits, the average weight of which is 75-100 g, very dense, characterized by suitability for long-term transportation, and in terms of strength they are not inferior to foreign varieties and hybrids. The shape and weight of fruits of varieties of both groups are different, the yield and marketability of varieties is quite high, but the weight of 1000 seeds and seed productivity does not depend on these indicators, but is individual for each variety.

Relevance. The action of viral phytopathogens changes the quality of the male gametophyte, which ultimately leads to a decrease in plant productivity. So, information on the features of the variability of morphofunctional characteristics of the microgametophyte becomes topical. Taking into account the expression of a part of the plant genome in pollen, the male gametophyte can be used as a reliable system for assessing the response of genotypes to the action of viral pathogens. Presuming that the problems of variability of characteristics of the male gametophyte in conditions of viral pathogenesis have not been enough studied, as well as the main factors determining the variability have not been identified, the aim of the research was to study the effect of viral phytopathogens on the male gametophyte characters in tomato.Material and methods. Hybrids F1 and varieties of tomato were used in the experiments. Plants were grown in a greenhouse. They were inoculated with tobacco mosaic virus (TMV) or tomato aspermia virus (TAV) in the 4-5 leaf phase. To determine the quality of pollen, flowers of control and infected plants were collected; pollen was isolated and sown on a nutrient medium. The preparations were analyzed under microscope. The viability of the pollen and the length of the pollen tubes were assessed, and the ratio of these indicators was calculated.Results. Infection of plants with viruses changes some functional characteristics of the male gametophyte. The responses manifested as stimulation, inhibition, or neutral effect. The main sources of variability in characters of pollen were the genotype and viral agents. In viral pathogenesis, unequal indicators of pollen grains were found in terms of the rate of germination and growth of pollen tubes (PT). Analysis of the heritability coefficients of the ratio of pollen viability and PT length (experiment / control) revealed positive dominance and overdominance in 70% of cases. Genotypes have been identified that combine a high level of viability when infected with different viruses. The prospect of their use in further research is proposed.

Relevance. The State Register of agricultural crops recommended for sowing on the territory of the Republic of Uzbekistan includes 47 hybrids and varieties of sweet pepper. Of these, 8 varieties and one F1 hybrid of domestic selection and 31 F1 hybrids of foreign selection (State Register, 2021). However, many of them, especially those of foreign selection, do not meet the requirements of the local market and are not adapted to local climatic conditions. In this regard, a preliminary test of varieties and hybrids included in the State Register, as well as F1 hybrids offered by foreign producers, was carried out in order to identify the most promising varieties for the conditions of the Central zone of Uzbekistan.Material and research methods. A preliminary tests included 20 varieties and F1 hybrids: 7 varieties and 1 hybrid F1 of domestic selection, 2 varieties and 10 F1 hybrids of foreign selection. The experiments were laid on the experimental base of the Research Institute of Plant Genetic Resources.Results. As a result of a comprehensive assessment of 20 varieties and hybrids of F1 sweet pepper, promising samples were identified for both breeding and industrial use. The sources of early maturity can be the Abai and Claudio hybrids, with the duration of the period "seedlings - biological ripeness of fruits" 97-99 days. To create large-fruited varieties in breeding work, F1 hybrids should be used: Procraft, Dallas, Magno, Claudio, Gemini and Zumrad variety. For breeding thick-walled and very thick-walled varieties and hybrids, the varieties Dar Tashkenta, Sabo, Nargiza, Lastochka, Podarok Moldova, Shodlik, Zumrad, etc., as well as F1 hybrids Procraft, Cadia should be used. High total (43.0-54.1 t/ha) and marketable (40.1-50.5 t/ha) yield was noted in hybrids F1. The most promising hybrids are Cadia, Procraft, Magno, Dallas with a total yield of 50.1-54.1 t/ha, against 47.5 t/ha for the F1 Zhaikhun standard. The total and marketable yield of the tested varieties was significantly lower compared to hybrids F1 and amounted to 33.5-38.6 and 30.7-35.7 t/ha, respectively.