The aim of the research was to study the weather risks when growing the main commercial citrus crop, mandarin, in the subtropics of Russia. The most informative sources for a complex of environmental factors are temperature and precipitations. The characteristics of the main weather factors are given, which can determine both the optimal growing conditions for the mandarine (Citrus reticulata Bl. var. unhiu Tan.) varieties ‘Unshiu’, ‘Iveria’, ‘Kovano-Vase’, ‘Miagava-Vase’, and limiting factors of plant cultivation in the studied region. Phenological observations have established that the first phase of “budding” depends on the sum of temperatures in March-April. It was 113 °C in 2015, 225 °С in 2016, 183 °С in 2017 and 244 °С in 2018. Flowering begins in May-June when the sum of effective temperatures reaches 502 °С, at min 490 °С and max 512 °С. The duration of the full period, from «budding» to «fruit ripening», varies depending on weather conditions: temperature, precipitation, and can last from 170 to 191 days. A more significant role in the timing of the onset and duration of the phenological phases of mandarin development is played by the water-thermal regime of the year. Weather factors manifested themselves on the growth processes of the studied varieties of mandarin. The total length of growth in ‘Iveria’ and ‘Kovano-Vase’ was higher than that in ‘Unshiu’ and ‘Miagawa-Vase’. The same feature was noted in the growing shoots of the vigorous variety ‘Unshiu’, it was 8.5 cm, and of the medium-sized ‘Iveria’ — 7.5 cm. For the dwarf forms ‘Kovano-Vase’ and ‘Miagawa-Vase’ it was 7.5 cm and 6.8 cm respectively. Weather conditions and the limiting factor (lack of atmospheric precipitation) have a negative impact not only on the timing of the main phenological phases of mandarin development (flowering, second growth of shoots), but also on their productivity.

The aim of the work was the biological assessment of the formation of productivity of winter apple varieties and the identification of the most promising for cultivation in the conditions of Southern Dagestan. The research was carried out in 2017-2020 in the twenties in the scientific and experimental landfill. The objects of research were winter apple varieties Renet Simirenko, Starkrimson, Winter saffron 2006 planting on the rootstock M4. In the years of the research, the weather conditions did not differ from the average annual ones and were always favorable for the fruiting of apple varieties, it should be noted that they are typical for the entire southern plain zone. All the studied apple varieties were distinguished by the regularity of fruiting, so the spur variety Starkrimson had a high productivity of about 238–324 c/ha for 4 years. It is established that the variety has a high annual yield and early fruitfulness, due to its low growth, and is also the most technologically convenient. It was revealed that the average weight of Starkrimson apple fruit (M4 rootstock) at the age of 11 years was 162 g, and the maxi- mum fruit weight reached 185 g. The differences between the studied varieties of Renet Simirenko (control) and Winter saffron were significant. In the control variety, the fruits were larger (132.5 g) than in the Winter Saffron variety (58.8 g). Mathematical processing of the results of the experiment confirms the reliability of the obtained increase in yield of apple trees on experience and years of research. We recommend varieties that have high productivity, taste and commercial qualities of fruits, and drought resistance for conditions characterized by aridity, an abundance of heat and light. The results of the work can be used to replenishment of the gene pool of winter apple varieties in Southern Dagestan, as well as to analyze the soil and climatic conditions for existing plantings of southern fruit growing. The soil-climatic and landscape-relief conditions of the microzones of Southern Dagestan are the most favorable for stable fruiting in accordance with the agro-climatic requirements of the culture.

The article presents the results of studying the adaptive potential of promising pear varieties of domestic breeding in the conditions of the steppe zone of the Southern Urals (Orenburg region). The aim of the work was a comparative assessment of pear varieties with different ecological origins in terms of yield, ecological plasticity and stability. The research was carried out in 2018–2020 on the experimental plot of 2002 planting of the Orenburg branch of the Federal Horticultural Research Center for Breeding, Agrotechnology and Nursery. The objects of research were promising varieties of pears of domestic breeding Pingvin, Permyachka, Sverdlovchanka, Isetskaya Sochnaya, Lel, Povislaya, Uralochka, Chizhovskaya, Samara Krasavitsa, Gvidon, Lada. The check variety was the variety Krasnobokaya (K). The agro-climatic conditions in the years of research were diverse, which allowed us to reliably assess the adaptability of the studied varieties. The studies were carried out in accordance with generally accepted methods. The parameters of ecological plasticity and stability (bi, Si2) were calculated according to the method S. A. Eberhart and W. A. Russell as presented by V. A. Zykin et al. The method is based on the calculation of linear regression (bi), which characterizes the ecological plasticity of the variety, and the mean square deviation from the regression lines (Si2), which determines the stability of the variety under environmental conditions. Statistical processing of the obtained data was carried out by the method of variance analysis according to Dospekhov B. A. using the analysis package Microsoft Office Excel 10. As a result of the conducted research, it was revealed that the highest yield in the conditions of the steppe zone of the Southern Urals on average over the years of research were intensive varieties: Pingvin (6.6 t/ha; bi = 1.22), Sverdlovchanka (7.5 t/ha; bi = 1.25), Lel (8.4 t/ha; bi = 1.79); environmentally plastic varieties Isetskaya Sochnaya (8.1 t/ha; bi =1.1), Lada (7.4 t/ha; bi = 0.57), as well as the neutral variety Povislaya (6.9 t/ha; bi = 0.33). At the same time, all varieties showed high environmental stability.

With the development of horticulture in the Siberian regions, cultivation and introduction of breeding developments, the demand and requirements for varieties have changed. Insufficient winter hardiness in critical winter periods, moral aging of varieties and minimal fruit weight indicate the need for further development and improvement of the assortment by creating new varieties based on the assessment of the existing assortment, which will help to increase the production of environmentally safe fruits and preserve the productivity of apple plantations in the harsh conditions of Siberia. The paper presents an assessment of apple fruits of different maturation periods growing on the lower terrace of the Vs. M. Krutovsky Botanical garden in the period from 2018 to 2020 according to the following biometric characteristics of large fruit: height, diameter, weight of fruits. As a result of the conducted observations, a significant variability in the size of apple fruits was revealed, depending on the varietal affiliation and the year of fruiting. Varieties and individual genotypes of different maturation periods growing on the territory of the lower terrace of the Botanical Garden with the maximum weight and size of fruits were selected: Antonovka vulgaris, Bely naliv, Bismarck, Krasnoyarsk Siberian, Papirovka, St. Petersburg summer, which shows a positive result under the influence of the features of the Siberian summer, namely, the insufficiency of the length of the frost- free period and the sum of positive temperatures, in a sharply continental climate. The studies also included an assessment of the taste qualities of fruits. Breeders of Siberia have created varieties whose fruits are similar in size to those of European varieties. Their high winter hardiness in the regions where breeding was carried out was confirmed in the climate conditions of the research area.

In the pomological garden on the territory of the Voronezh State Agrarian University named after Emperor Peter I, scientific research is conducted on the study of graft — rootstock combinations of plum selection of the Department of Fruit and Vegetable Growing and research institutions of the country. Plum plantations are represented by varieties of domestic plum (Prunus domestica L.): Voronezhskaya compotnaya, Bolkhovchanka, Universalnaya and Utro, grafted on seed — seedlings of cherry plum (control) and clonal rootstocks: OP-23-23, SVG-11-19 and VSV-1. The research was carried out in the period 2017–2019 in a garden planted in the spring of 2013 according to the 6×4 m scheme. The highest indicators of crown habit and yield, ranging from 8.8 for the Bolkhovchanka variety to 12.7 t/ha for the Universalnaya, were observed in trees grafted on seed rootstocks (k). At the same time, the quality of fruits in such plantings was inferior to the graft-rootstock combinations on clonal rootstocks. The most restrained parameters of the crown and the minimum yield (5.1-6.3 t/ha) were observed in the studied varieties on the low-growing rootstock VSV-1, and the volume of the crown, depending on the variety, changed slightly and was in the range of 1.7-2.8 m³. On medium-sized rootstocks of OP-23-23 and SVG-11- 19, the maximum yield (7.7-8.9 t/ha) was determined for the Bolkhovchanka, Universalnaya and Utro, and the minimum yield was for the Voronezhskaya compotnaya — 6.3-7.3 t/ha. Analyzing the suitability of graft-rootstock plum combinations for compacted plantings by the value of specific productivity, it can be recommended on medium-sized rootstocks OP-23-23 and SVG-11-19 for varieties Bolkhovchanka and Utro (6.5-7.7 kg/m³), on the rootstock SVG-11-19 — Universalnaya (6.6 kg/m³) and the studied varieties of low-growth rootstock VSV-1 (5.1-8.5 kg/m³).

The purpose of research was the study of vegetative organs reaction in strawberry seedling to the components of organic substrate and phytoregulation. Seedlings of 6 strawberry varietiess, organic substrate (fluffed peat, peat, sand) and growth phytoregulators (Radifarm and Atlante plus) were studied. Analysis of the results of experiments in 2019–2020 showed that the use of a substrate based on dissolved peat with perlite significantly affected the increase in root length by 15.1–27.6 % compared to the control (a mixture of peat and sand) on average for the studied varieties. The root saturation indice with plug volume of (40 cm3) differed significantly compared to the control namely by 27.9–26.8 % for the studied variants. We have established the biological affectiveness of using the studied phytoregulators on root system in low volume plugs (cassettes) on all studied varieties. The root saturation did not differ in the variants with Radifarm and Atlante plus and averaged 5.2-5.4 cm/cm3 which was significantly higher compared to the control on 28.3–46.0 %.

The research was carried out in 2009, 2010, 2017, 2018 on the grape plantations of the experimental site of the Novocherkassk branch of the All-Russian Research Institute for Viticulture and Winemaking (Novocherkassk, Rostov region). In the vineyard of the Kunlean variety (rootstock Kober 5BB), planted in 2003 according to the 3x1.5 m scheme, the experiment provided for two options with bush shapes: a two-sided horizontal cordon and a two-sided horizontal cordon with a ground sleeve and a recovery knot. On the root-related plantings of grapes tolerant to phylloxera of the Pervenets Magaracha variety, planted in 1986 according to the same scheme, the forms of the bush were studied: a two-sided horizontal cordon, a long-sleeve and a two-sided horizontal cordon with a ground sleeve and a recovery knot. The load of shoots in all variants for both varieties was the same — 40 shoots per bush. The purpose of the research was a comparative analysis of the fruitfulness, yield and quality of grapes, depending on the shape of the bush. As a result of many years of research, it was revealed: on the Pervenets Magaracha variety, the highest rates of fertility (the share of fruit-bearing shoots is 82 %, K1 — 1.45) and yield (14.0 t/ha) were in plantings with the form of bushes-a two-sided horizontal cordon with a ground sleeve and a recovery knot. The quality of the grapes was approximately equal in the variants with a long-sleeve and shaping and a two-sided horizontal cordon with a ground sleeve. The data on the annual growth of shoots were the lowest in the variant with a single-arm stem shape (shoot volume of 7.9 cm3, maturation of 44 %). On the Kunlean variety, the highest parameters of fruitfulness (the share of fruit — bearing shoots is 85 %, K1 — 1.80), yield (27.0 t/ha) and the quality of berry juice (230 sugars and 7.8 g/cm3 titrated acids) were in plantings with the form of bushes-a two-sided horizontal cordon with a ground sleeve. Data on the annual growth of shoots were also higher in this variant (shoot volume 35.0 cm3, aging 68 %).

The objects of research were the landscapes of the lands of the right bank of the Don River from the village of Bessergenevskaya to the farm of Starozolotovsky and the banks of its tributaries of the Kerchik River, the Sukhoi Donets River and the Seversky Donets River at the mesorelief level and landscape-forming factors-geology, relief, soil and groundwater. The research method was the study of historical and literary data on viticulture on the Right Bank of the Nizhnij Don, obtaining the necessary landscape- forming data by manual drilling of wells to a depth of up to 10 m with a morphological description of their soil, geological and hydrogeological profile, with the selection for chemical analysis of soil and ground water samples made in the design and survey bureau of the Institute. The purpose of the research was to study the factors limiting the productivity of vineyards, the optimal ampeloecological conditions of the microlandscapes of the Nizhnij Don for the selection of microzones of high-quality winemaking. As a result of the conducted research, the characteristic of the entire variety of landscapes of the right bank of the lower Don and its tributaries from the village of Bessergenevskaya to the farm of Starozolotovsky, corresponding taxonomic levels, qualitatively different from each other by landscape-forming factors, taking into account the degree of their influence on plant growth, yield, quality of grapes and products obtained from it, is given. Two ecological and landscape zones of grape cultivation on the right bank of the Nizhnij Don are identified — the zone of sloping lands and the zone of steppe landscapes of the watershed territory, with the greatest attention paid to the first zone, the conditions of which differ from the second zone in a large variety and are most suitable for traditional viticulture of the Don. Limiting factors in the development of the slope lands of the right bank of the Nizhnij Don are their great steepness, which are deformed by ancient landslides and erosion processes,ъ the inaccessibility of groundwater for grape roots, which in most cases are blocked by landslides and a thick layer of deluvium.

In the Orenburg region, strawberry Fragaria×ananassa (Duch.) is a popular berry crop and its planting areas have been expanding in recent years. This inevitably leads to the spread of pests, among which one of the most dangerous is the common spider mite Tetranychus urticae (Koch.). The abundance and bioecology of T. urticae in this region have not been studied. The studies covered almost all zones of the region (eastern, central, western), differing in climatic features. Sampling was carried out every 7-10 days, on 10 accounting sites randomly located in plantings and in natural habitats of the phytophage. 5 leaves of different ages were taken from each registration plant. The leaves were examined on the day of collection in the laboratory under an MBS- 9 binocular microscope to see if they were colonized with spider mites. Phenophases of plant development were assessed visually. A high number of the pest was noted in commercial plantations of culture, in the central part of the region (Orenburg district). In the climatic conditions of the region, the common spider mite can give up to 7 generations during the growing season, with a conditional interval of 14 days and a correction for weather conditions. The peak in numbers is observed from the third decade of June to the third decade of July. Correlation analysis showed close links between the dynamics of development and the number of the pest with the average daily temperature of the ambient air — the correlation strength of characteristics is above average, the direction of the correlation is positive (Orsk I_PR = 0.64, Orenburg region I_PR = 0.68).

On the basis of many years of research, a strategy for combating fire blight was developed, including a set of measures aimed at reducing the infectious load in gardens, curbing the intensity of pathogen reproduction, and increasing plant resistance to disease. On the basis of this strategy, a complex of control measures was developed, including the autumn pruning of affected organs in accordance with quarantine requirements, whitewashing of trunks and skeletal branches with lime with the addition of 4 % copper sulfate and spraying with the fungicide Cosside 2000, v.d. (3 kg/ha); in the spring, prophylactic spraying with the same fungicide before bud break; during the flowering period, double spraying with biological preparations of Fitolavin, VRK (2 l/ha); after flowering, during the period of ovary abscission, double spraying with growth regulator Regalis plus (d.v. prohexadione calcium), 1,25 kg/ha. A production test has shown that complex measures developed on the basis of a fire blight control strategy effectively suppress the disease at the site of infection. The biological efficiency was 97.5 % with an increase in yield 36.2 %.

Receiving of high yields of sea-buckthorn in most regions of its cultivation is holding back by the wide distribution and high harmfulness of the sea-buckthorn fly (Rhagoletis batava obscuriosa Kol). The main problem carrying out in protective measures against these vermin consist in the fact, that sea-buckthorn is a medicinal crop and pesticide residues for its fruits are not allowed. The biological method of protection, based on the use of the biogenic preparation Fitoverm (10 g / l), guarantees an environmentally friendly yield, but in the extreme continental climate of the Altai Territory, it does not always provide reliable protection of the crop from the sea buckthorn fly. The wide introduction of the preparation Fitoverm into production is constrained by the high cost of the preparation. In case of force majeure (precipitation before processing, temperature changes, etc.), a low-risk chemical preparation “Fufanon” (570 g/l of malathion) can be used to protect against sea buckthorn flies. The article discusses ways to reduce the consumption rates of the biogenic preparation “Fitoverma” and “Fufanon” in the protection of sea buckthorn from sea buckthorn flies due to their use in combination with a micro supplement and the preparation “Neo”, developed at the Research Institute of Horticulture of Siberia on the basis of natural BAS, as well as a tank mixture of preparations “Fitoverma” and “Fufanon”. The dependence of the efficiency of treatment against sea buckthorn flies on environmental conditions is shown. Fitoverm (10 g / l) at a concentration of 0.3 %, depending on environmental conditions, provided an efficiency of 94.2-99.4 % with reduced consumption rates of the drug due to its combined use with a microadditive and the drug “Neo” 92.5 -100 %, tank mixture “Fitoverma” and “Fufanon” 96.9-100 %. The decrease in residual amounts of malathion by 1.6-2.6 times was ensured by the tank mixture of Fufanon and Fitoverma in half dosages, as well as a half dose of Fufanon in combination with a microadditive.