Relevance. Powdery mildew is one of the most common and harmful diseases of cucumber (Cucumis sativus L.) in open and protected ground. Moreover, in the closed ground, the harmfulness is higher than in the field. The yield of cucumber, due to the defeat of plants by powdery mildew, decreases by 30-50%, and in some cases by more than 70%. The creation of modern cucumber hybrids is impossible without the constant involvement in the breeding process of new sources of economically useful traits, including resistance to real powdery mildew. It is very important to combine in one line both a high degree of parthenocarpy, and the female type of flowering, and resistance to the most harmful diseases. We tried to solve this problem in our work.Materials and methods. The experience was laid in 2018-2022 in the Odintsovo district of the Moscow region on the basis of the head institution of the Federal State Budgetary Scientific Institution Federal Scientific Vegetable Center (FSBSI FSVC) in the conditions of a spring ground greenhouse of the Block type, on a natural infectious background. On the basis of the laboratory of breeding and seed production of pumpkin crops, 27 collectible and about 50 breeding samples of parthenocarpic cucumber were studied. The article presents an assessment of the resistance to this powdery mildew of 36 of the most aligned and most valuable cucumber breeding samples in terms of a complex of economically useful features. 2-3 families, 6 plants in each, were evaluated for each sample for 2 years. During the entire growing season, the intensity of powdery mildew damage was assessed on a four-point scale and the spread of the disease in %.Results. Among the collection samples of cucumber, on a natural infectious background, two hybrids of the agrofirm BEJO ZADEN B.V. were not affected by powdery mildew: Amur 1801 F1, Artist F1, a hybrid without a name of the agrofirm MONSANTO HOLLAND B.V., conventionally named – Semenis F1 and hybrid Kibria F1 of the agrofirm RIJK ZWAAN. To a small extent, less than one point, they were amazed: Orpheus F1, Merengue F1, Marinda F1, Masha F1, Othello F1, List F1, Adam F1, SV 4097 F1 and Krasotka F1. 11cucumber breeding samples selected in previous years of research on a complex of economically useful signs that were not affected by this disease during 2 years of research were identified. Work will continue to evaluate these lines for resistance to real powdery mildew on an artificial infectious background.

Relevance. Alternaria dauci, Alternaria radicina and Fusarium oxysporumare wide spread and harmful fungal diseases of carrot (Daucus carota L.) in the Russian Federation and in the world. Total losses of roots from these diseases are 35-70%. Obtaining of new varieties and hybrids resistant to these pathogens is complicated by the fact of polygenic control resistance traits to fungal diseases of Alternaria and Fusarium genus. Interaction of polygenic resistance traits with environmental factors causes the soft character of changing these traits: effects of interactions between alleles and genes are changed, the dominant effect become weaker, additive effect become stronger. So, we can say about of the tolerance to complex pathogens for that case.The goal of our study is to determine the heritability of tolerance to fungal pathogens Alternaria dauci and Fusarium oxysporum by hybrids F1 of carrot.Materials and methods. Materials of studies were 7 basic lines with different types of roots; 7 prospective hybrids F1 and mycelium of Alternaria dauci and Fusarium oxysporum with spores (for inoculation). Methods of studies were: evaluation resistance of lines and hybrids F1 (seedlings, adult plants and roots) at different types of infection backgrounds; dispersion and correlation analysis. Resistance the basic lines of carrot to fungi of Alternaria and Fusarium genus was evaluated step-by-step, using several types of artificial and natural infection backhybrids F1. Tolerant samples were selected and they were used in crossings. F1 – hybrids have been obtained and they have been evaluated at artificial and natural backgrounds.Results: 1. One tolerant male form № 1268 and 6 female forms with weak sensitivity to fungi of Alternaria and Fusarium genus were selected from basic material. They were used in crossings. hybrids F1 have been obtained. 2. Analysis the heritability of carrot resistance to fungal pathogens Alternaria dauci and Fusarium oxysporum identified, that such type of resistance inherited by father’s type. 3. Using tolerant carrot line № 1268 in crossings as the male form and 6 female forms with weak sensitivity to fungal pathogens Alternaria dauci and Fusarium oxysporum increased significantly the percent of tolerant plant in 3 F1 – hybrid population under artificial infection on provocative infection background.

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.

RelevanceRecently, breeding work with cabbage is aimed at developing F1 hybrids, which provide the population with year-round production. The main requirements for hybrids: excellent presentation with appropriate taste, high yield stability, morphological uniformity, resistance to major diseases and tolerance to pests, as well as high keeping quality during storage. In recent years, tobacco thrips is a serious problem for cultivation of cabbage. Plant resistance to tobacco thrips is becoming increasingly relevant, at the moment in the conditions of Krasnodar region. Since tobacco thrips is the most dangerous pest in the south and quickly adapts to poisons, development of resistant hybrids should be considered the most effective way to control.Methods The purpose of breeding work is to identify highly productive cabbage hybrids with high tolerance to tobacco thrips. It was previously found that late-ripening hybrids are less affected. Therefore, in our studies, we evaluated the effect of growing terms of the same hybrids in different years of research and on their damage with Thrips tabaci Lindeman. The direction of this work is to evaluate hybrids of cabbage for leaf damage by tobacco thrips and to identify sustainable hybrid combinations and their parental forms. Studies were carried out in the central soil-climatic zone of the Krasnodar Territory. The object of research was medium-ripening hybrids of cabbage. ResultsThe degree of susceptibility of hybrids to tobacco thrips varied significantly during the three years of research, but there were distinguished lines that established themselves as the most stable: Yas25p, Ts139, Agrbh82, Pi 714, 272Br-22. Hybrid combinations with these lines showed the least loss of marketable yield and the minimum number of affected leaves in each year of the study. Of the zoned hybrids, the Revansh F1 hybrid shows a high tolerance. It was found that a later planting period significantly reduces the degree of thrips damage.

Relevance. False powdery mildew (peronosporosis) (the causative agent is Pseudoperonospora cubensis (Berk. et Curt.) Rostow.) – the most harmful disease on cucumber in the open ground, spring film and winter greenhouses in the autumn crop turnover. In the laboratory of breeding and seed production of pumpkin crops of All-Russian Research Institute of Vegetable Breeding and Seed Production, currently FSBSI FSVC, continuous work is underway to create varieties and hybrids of cucumber resistant to this disease. To create new competitive hybrids of cucumber of the parthenocarpic type, a lot of work was done on the selection of parental forms that differ in a complex of economically useful signs, including tolerance to false powdery mildew.Results. During 2 years of research, in the open ground conditions of the Moscow region, on a natural infectious background, the lines of parthenocarpic cucumber most resistant to false powdery mildew were selected: Pr. F6 1, 24-905 RZ F4-5, Excel. F5 b/w 1, (Hac. x Hub.) F4. During the second (30.08.) and third (08.09) counts, in both years of research, according to the lesion score, they were at the level of a stable standard - the Surazhevsky variety. In 2022, in the conditions of unheated spring greenhouses of Primorsky region, two hybrid combinations of 24-905RZ F4 x Pr. F11 and Kar. F6 x Pr. F11 were distinguished for resistance to peronospore. At the end of August, they were struck by 0.5 and 0.8 points, respectively, less than the standard hybrid German F1. The resulting hybrid combinations were obtained with the participation of cucumber lines of the parthenocarpic type, the most tolerant to false powdery mildew in the open ground conditions of the Moscow region in 2022 and 2023. This indicates that the isolated samples can serve as gene sources of resistance to false powdery mildew.