Background. Recently, an increased interest in crop landraces has been observed among scientists working with plant genetic resources (PGR). Institutes have been organizing collecting missions to explore old varieties still cultivated locally. Attention paid to landraces is also associated with the introduction of GIS technologies into PGR studies. The N. I. Vavilov All-Russian Institute of Plant Genetic Resources (VIR) holds a unique collection of spring bread wheat landraces. One of the Institute’s top priorities is to develop and maintain a passport database, using a set of fields specifically fit for landraces.

Analysis of the passport database. The passport database ‘Spring Bread Wheat Landraces in the VIR Collection’ is analyzed here. The database contains information on 5,925 accessions and has 36 fields. Statistical data are presented for the main fields: origin, collection site, botanical variety, year of registration in the collection, donor institute or expedition, and collector’s name.

Surveying vegetation in various areas within Russia is an important link to successful management of plant genetic resources. Species and forms of wild perennial legumes and forage grasses possess complex adaptability to local environments. The aim of VIR’s collecting mission to Voronezh and Tambov Provinces in 2016 was to replenish the preserved genetic diversity of leguminous and perennial forage crops with samples of interest for breeding for fodder and seed productivity and resistance to limiting environmental factors. The task of the collecting mission was to explore the territory and collect seeds of wild perennial forage and leguminous plants. The exploration route and collecting sites are indicated on the map. Geographical coordinates and descriptions of habitats were recorded for 38 collecting sites. During the survey of fourteen districts in Voronezh Province and two districts in Tambov Province, 169 plant samples were collected, including 140 forage plant accessions (33 species) and 29 leguminous ones (9 species). The most frequently occurring species were identified: Poa pratensis L., Melilotus officinalis (L.) Pall., Medicago falcata L., Vicia angustifolia L. and Lathyrus tuberosus L. Plants of Onobrychis arenaria (Kit.) DC. occur throughout Voronezh Province in meadow-steppe communities. Of interest are the samples of Agropyron pectinatum (Bieb.) Beauv. collected on the northern border of its area of distribution; three species of lower-growing fescue (Festuca rubra L., F. valesiaca Gaudin. and F. pseudovina Hack. ex Wiesb.); a perennial form of Medicago lupulina L.; a sample of Lotus corniculatus L. found on chalky outcrops of the Kalach Hills; red (Trifolium pratense L.), golden (T. aureum Pollich.) and strawberry (T. fragiferum L.) clovers from the valley of the Khoper River; pisiform vetch (Vicia pisiformis L.) from Kalach District and hairy vetch (V. villosa Roth) from Povorino District of Voronezh Province. The materials collected by the team were added to the holdings of VIR and are available for further study and use in breeding.

Background. For the Trans-Urals, characterized by unstable climate over the years (alternating droughty and excessively moist years, recurrences of colds in spring, possibility of early frosts, etc.), grain quality is a prioritized genetic trait in spring bread wheat cultivars. In Kurgan Province, the share of thirdclass wheat varied since 1994 from 43% to 96%; only in the recent unfavorable years (2015 – 2017) it dropped to 11 – 27% due to rust epidemics. The aim of the study was to characterize the genetic potential of grain quality and its phenotypic implementation in promising cultivars bred at Kurgan Agricultural Research Institute and officially released for cultivation in the region.

Materials and methods. The capacities of the KASIB4 – 13 (Kazakhstan–Siberia Wheat Improvement Network under the auspices of CIMMYT) represented by 17 breeding centers in Kazakhstan and Siberia were used to assess grain quality of 14 cultivars with different maturation time bred at Kurgan Agricultural Research Institute. Quality assessment was performed with due regard to the standards of Kazakhstan, CIS, and leading exporting countries, thus combining local and international levels, and employing genetic, biochemical and technological grain quality levels under different soil and climate conditions.

Results and discussion. Generally, all cultivars demonstrated protein and gluten content and the level of vitreousness sufficient for strong and valuable wheat. The selected percentage was 92% for hard grain and medium hard grain wheat forms, up to 94% for high-protein and high-gluten ones, and up to 57% for genotypes without 1B/1R wheat/rye translocation. In terms of sedimentation, 86% of the genotypes were predicted to belong to the strong and valuable wheat class; according to the composition of HMW glutenin subunits, mixing quality and flour strength (W), 30 – 42% were identified as high-quality genotypes. The in-depth study of grain quality within the KASIB environmental network revealed heterogeneity among cultivars in a number of genetic and biochemical parameters and provided an opportunity to select high-quality genotypes by marker characteristics and technological properties, which is likely to improve the efficiency of intra-cultivar selection and overall quality assessment of cultivars.

Consideration is given to the possibility of using LED light sources with different ratios of red (650 - 660 nm), orange (600 - 610 nm) and blue (440 - 450 nm) light in the light flux in the rooting stage of garden strawberry (Fragaria × ananassa (Duch. ex Weston) Duch. ex Rozier) grown in vitro. The study covered a sizable diversity of strawberry cultivars (selected from the in vitro collection): ‘Borovitskaya’, ‘Vityaz’, ‘Zenga Zengana’, ‘Khoney’, ‘Tsaritsa’, ‘Kubata’, ‘Dukat’, ‘Marmalada’, ‘Valenta’, ‘Rusich’, ‘Krasavitsa Zagorya’, ‘Neznakomka’ and ‘Roksana’, thus ensuring quite diversified results. It was established that the use of LED sources with an increased content of red light in the light flux increased the rooting percentage (1.15-1.25 times) and the number of roots per one microcutting (1.29-1.77 times) in in vitro culture, as compared with fluorescent lamp lighting. It was observed that with different spectral compositions of light the rooting ability of microcuttings was cultivar-specific.

Background. An extremely important task today is to develop new hulless barley cultivars, capable of yielding large and high-quality grain harvests, and introduce them into agricultural production. Objective. The purpose was to study three hulless barley cultivars ‘Omsky golozerny 2’, ‘Omsky golozerny 4’ and ‘Maysky’, developed at Omsk Agrarian Scientific Center, in order to describe their agrobiological characteristics.

Materials and methods. The experimental part of the work was carried out in 2015–2017 on the experimental fields of Omsk ASC in the southern forest steppe (third crop rotation after the wheat predecessor; fourth crop after fallow). There were 4 replications on the plot of 10 m². The seeding rate was 4 million viable seeds per 1 ha. Agricultural practice used in the experiments was conventional for West Siberia. Parameters of stability and plasticity were calculated according to Eberhart and Russell, Wricke; adaptability, according to Zhivotkov; homeostasis, according to Khangildin; stress tolerance and compensatory ability, according to Rossielle and Hemblin.

Results. Many years of breeding work at Omsk ASC resulted in the development of three hulless barley cultivars: ‘Omsky golozerny 2’ (listed in the State Register of the Russian Federation for regions 9, 10 and 11), ‘Omsky golozerny 4’ (submitted for the State Crop Variety Trials in 2017), and ‘Maysky’ (not included in the State Register). The new hulless barley cultivar ‘Omsky golozerny 4’, considering its higher productivity (+1.36 g to the reference in 1000 grain weight, and +0.73 t/ha to cv. ‘Maysky’), in the yield of nutrients per area unit equaled the reference ‘Omsky golozerny 2’, but exceeded ‘Maysky’ (+47.2 kg/ha of protein, +390 kg/ha of starch, and +42.4 kg/ha of crude fat). ‘Omsky golozerny 4’ was also characterized by stability (stability = 4.8), increased compensatory ability (3.29) and adaptability (103%). There was an increase in productivity with improved growing conditions (ecological plasticity = 1.25). ‘Maysky’ had higher stress tolerance (–1.35), while the reference ‘Omsky golozerny 2’ showed increased homeostasis (0.118). Thus, ‘Omsky golozerny 4’ exceeded the previous two cultivars in adaptability and stability.

Background. In Leningrad Province, winter rye is an irreplaceable cereal crop for food and feed. At present, a reduction of the acreage under rye is observed. This situation may be changed by developing rye cultivars capable of maintaining high and stable protein content across variable natural environments.

The objective of the research encompassed 9 winter rye cultivars developed by V. D. Kobylyansky and O. V. Solodukhina at VIR, all recommended for cultivation in this area.

Materials and methods. The experimental part of the work was carried out in 2012–2017 in the fields of Pushkin and Pavlovsk Laboratories of VIR. Nine low-pentosan winter rye cultivars bred at VIR were analyzed. Sowing time was within the period from August 28 to September 11. Agricultural practice used in the experiments was conventional for the Northwestern Region. The area of the plot was 10 m²; there were three replications. Seeding rate was 350 seeds/m² or 3.5 million viable seeds per hectare. Analysis of variance was used for mathematical processing. Parameters of adaptability, stability, plasticity and stress resistance were calculated for the “grain protein content” indicator.

Results. Protein content in grain for the studied winter rye cultivars in the environments of the Northwest region averaged 10.3% and varied from 8.7% to 12.2% depending on environmental conditions and hereditary features of the cultivars. It was confirmed by the results of the analysis of variance: the share of the ‘year of trial’ factor’s effect on protein content was 71.9%. The best conditions for increased protein content were observed in 2012, 2013 and 2016 (10.7%, 11.9% and 12.2%, respectively). The analysis of average protein content in grain showed that the cultivars ‘Ilmen’, ‘Vavilovskaya’, ‘Krasnoyarskaya universalnaya’, Novaya Era, ‘Yantarnaya’ exceeded the reference cultivar ‘Era’ by (1.0 – 10.0%). The most adaptable in the context of grain protein content under the conditions of the Northwestern Region were the winter rye cultivars ‘Ilmen’, ‘Era’, ‘Yantarnaya’, Novaya Era, and Rushnik 2. The sum of their ranks according to the coefficients of variation (V), environmental plasticity (O), relative trait stability (St²) and homeostasis (Hom), as well as each cultivar’s adaptability coefficient (AC), stress resistance level (Y min – Y max) and compensatory ability (Y min + Y max/2), was 13–31 units.

Conclusion. Rye cultivars ‘Ilmen’, ‘Era’, ‘Yantarnaya’, Novaya Era, and Rushnik 2 possess high adaptability and can maintain high protein content levels in grain under widely varied environmental conditions in the Northwestern Region of Russia.

Background. For the present-day oat breeding, the task is to develop adaptive cultivars with high yield potential, high quality of products, fairly early-ripening habit, and resistance to lodging and diseases. Breeding new cultivars with a complex of valuable characters, high yield, and high quality of products under varied environmental conditions requires well-studied source material. Selection of sources according to the basic economically useful traits is one of the main objectives in the study of the global diversity preserved in the oat collection.

Results and conclusion. The article presents the results of studying the oat accessions from Western and Central European countries, preserved in the VIR collection, under the conditions of Kuban Experimental Station of VIR (Krasnodar Terr.). Evaluation of the accessions in the field was targeted at such crop characters as the duration of the growing season, resistance to lodging, and field resistance to rust diseases. A structural analysis was performed in the laboratory to measure the weight of 1000 grains, the number of spikelets and grains per panicle, grain weight per panicle and per plant, and percentage of grain hullness. As a result of a three-year comprehensive field study of the newest oat cultivars bred in Western Europe in the environments of Kuban Experimental Station of VIR, sources of traits useful for breeding were identified, such as lodging resistance, field resistance to crown rust, high yield structure components (1000 grain weight, grain weight per panicle, number of grains per panicle, grain productivity). When using source materials in oat breeding practice, in addition to economically important traits, special attention should be paid to grain size, since this character, according to our data, has the most significant correlation with the grain yield of a cultivar. The identified sources of traits valuable for breeding may be included in breeding programs of Krasnodar Territory and other regions of the Russian Federation.

Background. The problem of a deficit in vegetable protein and the need to diversify agricultural produce require involvement of new and little-known crops, such as cowpea, in the production. Cowpea (Vigna unguiculata (L.) Walp.) is a high-protein leguminous crop; its breeding and production have been intensified in Russia only in recent years. The study of the VIR collection, carried out at the Institute’s branch in Astrakhan, makes it possible to disclose the crop’s breeding potential. Objective: Studying the range of variability and tracing the relationships of economically valuable traits in vegetable (green pod) cowpea under the conditions of Astrakhan Province.

Materials and methods. In 2008‑2010, a study was implemented at an experiment plot of the Astrakhan branch of VIR. Thirty- three accessions of green pod cowpea from the VIR collection were studied to analyze the variability of 12 phenotypic traits. Positive and negative correlations were identified between the following characters: interphase periods (flowering, industrial ripeness and seed maturation), shape of the shrub, lengths of the stem and to the first pod, length and weight of the pod, number of seeds per pod, presence of a parchment layer and fiber in pod valves, pod yield per plant, number of pods and peduncles, seed weight per plant, and weight of 1000 seeds.

Results and conclusion. Medium variability was observed for such characters as the interphase periods ‘shoots–industrial ripeness’ and ‘shoots– seed maturation’, number of seeds per pod, and weight of 1000 seeds: the coefficient of variation (CV) was 15‑18%. High variation was registered for the length and weight of the pod (CV = 26‑32%), shrub shape, stem length, and length of the stem up to the first pod (CV = 35‑37%). The widest ranges of variability were demonstrated in the quantitative yield characters of cowpea accessions: number of pods per plant (CV = 33‑49%), number of flower stalks (CV = 38‑51%), and seed weight per plant (CV = 38‑44%), which means that cowpea yield is quite susceptible to weather conditions. During the three years of studying, the lowest levels of variability in economically valuable traits were characteristic of the accessions of the early-ripening group: k‑668 and k‑873 (China); mid- ripening group: k‑971 (India); and late-ripening group: k‑141 (China). Cowpea pod productivity depended to the greatest degree from mean values of the number of pods per plant (r = 0,73) and the number of peduncles (r = 0,71). The identified correlations in the productivity components make it possible to optimize the selection of accessions promising as source materials for the development of new high-yielding cultivars.

Background. Sweet cherry is an unconventional fruit crop for the Northwestern region of Russia. Identification of cultivars adapted to the conditions of the northwest requires a comprehensive study of cultivars of different ecogeographic origin and, specifically, morpho-physiological characteristics of pollen, which ensure the productivity of sweet cherries.

Materials and methods. The field sweet cherry collection maintained at Pushkin and Pavlovsk Laboratories of VIR served as the material for the study carried out in 2017 at the Plant Diversity Long-Term Storage Laboratory. Twenty-four sweet cherry accessions belonging to five different groups were studied: I – Northwestern (bred at VIR); II – Central; III – Central Black Soil (all three are regions in Russia); IV – Belarus; and V – Estonia. Viability of pollen was assessed by germinating on an artificial medium with 10% sucrose and 0.6% agar. Pollen viability results were statistically processed using StatSoft Statistica 13.0 and Microsoft Excel.

Results. The initial viability of pollen for almost all varieties in 2017 was low. High percentage of pollen germination was characteristic of cvs. ‘Krasnaya sladkaya’ (gr. I, 50.0%), ‘Leningradskaya rozovaya’ (gr. I, 61.8%), ‘Adelina’ (gr. III, 53.5%) and ‘Zarya Vostoka’ (gr. III, 60.3%). After storage in liquid nitrogen, the level of pollen germination increased in all cultivars of groups I and V as well as in a number of cultivars from group II (‘Raditza’, ‘Iput’, ‘Rechitsa’ and ‘Fatezh’), group III (‘Zarya Vostoka’, ‘Rondo’ and ‘Orlovskaya rozovaya’) and group IV (‘Severnaya’ and ‘Vityaz’). Pollen viability after cryopreservation significantly decreased by 8.7‑17.3% in cvs. ‘Bryanochka’ (gr. II), ‘Alebastrovaya’ (IV),’ Bryanskaya rozovaya’ (II) and ‘Adelina’ (III). Pollen viability parameters (length of pollen tubes and percentage of germinated pollen grains) positively correlated prior to immersion into liquid nitrogen from r = 0,54 (gr. III) to r = 0,76 (gr. II), while after cryopreservation, they showed weak correlation (r = 0,28) in gr. I, and strong one (r = 0,79) in group IV. In the length of pollen tubes and the level of viability, the parent cv. ‘Leningradskaya chernaya’ had practically no connection with cv. ‘Raditsa’ (r = 0.09), while with cv. ‘Meelika’ the correlation was medium negative (r = –0.49); correlations between the parent cv. ‘Krasnaya plotnaya’ and cvs. ‘Sopernitsa’, ‘Bryanochka’ and ‘Vityaz’ were medium (r = 0.57) and high (r = 0.78 and r = 0.83), respectively.

Conclusion. In their level of pollen viability, the introduced sweet cherry cultivars are similar to or even exceed the cultivars native to the northwest (bred at VIR).

Background. Anthracnose, caused by phytopathogenic fungi of the genus Colletotrichum, is one of the most important strawberry diseases. Strawberry yield losses from anthracnose lesions can reach 80%. Most strawberry cultivars are susceptible to anthracnose. Therefore, identification of the initial forms carrying resistance genes is a necessary step toward successful breeding of anthracnose-resistant cultivars. Use of molecular markers will increase reliability of identification and enhance effectiveness of strawberry breeding.

Materials and methods. Biological material was represented by strawberry cultivars (Fragaria × ananassa Duch.) of various ecological and geographical origin. Total genomic DNA was extracted from the fresh leaves using the CTAB methods according to Puchooa (2004). To assess the allelic state of the Rca2 anthracnose resistance gene, the SCAR marker STS-Rca2_240 was used. The SCAR marker STS-Rca2_240 was multiplexed with the microsatellite marker EMFv020 used as the positive PCR control.

Results and conclusion. The SCAR marker STS-Rca2_240, mapping at about 2.8 cM from the Rca2 gene, was identified in the strawberry cultivars ‘Elianny’, ‘Troubadour’ and ‘Sudarushka’. Cvs. ‘Elianny’ and ‘Troubadour’ are presumably characterized by a dominant homozygous (Rca2Rca2) or heterozygous (Rca2rca2) genotype. Cv. ‘Sudarushka’ has the heterozygous state for the Rca2 anthracnose resistance gene (Rca2rca2). In the remaining cultivars studied, the marker STS-Rca2_240 was not detected (the prospective genotype is rca2rca2).

In comparison to other annual forage legumes, such as pea (Pisum sativum L.), advances in breeding vetches (Vicia spp.) are rather modest. One of the main obstacles in increasing the cultivation area under vetches is uncertain seed production, mostly due to their indeterminate stem growth and non-uniform maturity, with the genes controlling these important traits still unattested. In contrast, in wild populations of common vetch (V. sativa L.) the genes have been identified, isolated in this study, and mutant plants with more than usual two pods per node tested. Crossing these mutant genotypes with wild-type ones demonstrated that the number of pods in this vetch species is controlled by two genes, orthologs to FN and FNA in pea. If both genes are recessive, a plant will have more than two flowers per each node and, depending on not yet clarified environmental factors, more than two pods per node. Developing vetch cultivars with more than two pods per node may be one of the solutions for enhancing seed production in this crop.

Background. The environmental conditions in the northeast of the Russian Non-Black-Soil zone require development of barley cultivars with resistance to higher soil acidity, drought and diseases. Increased productivity in stressful environments was achieved by combining different breeding techniques, including application of cell technologies.

Materials and methods. Barley accessions from the unique collection of the N. I. Vavilov All-Russian Institute of Plant Genetic Resources (VIR) served as sources of useful traits. These accessions underwent field- and laboratory-based research at the FASC of the North-East, which was targeted at the main qualities of breeding value: grain yield, growing season duration, and resistance to lodging, diseases and soil stress. Cultivation of callus tissues and regeneration of barley plants were performed in vitro on artificial nutrient media modified by adding selective agents simulating the effect of natural stressors.

Results and discussion. After studying the accessions from VIR for various traits of breeding value for the environments of the Volga-Vyatka region, the following breeding sources were selected: cvs. ‘Dina’ (k‑29216, Russia), ‘Andrey’ (k‑30122, Russia), etc. for their earliness; ‘Belogorsky 90’ (k‑29770, Russia), ‘Syabra’ (k‑29917, Belarus), etc. for combined high yield and earliness; ‘Musson’ (k‑30968, Russia), ‘Fenix’ (k‑30835, Ukraine), etc. for lodging resistance; ‘Dina’ (k‑29216, Russia), ‘Medikum’ (k‑30962, Russia), etc. for disease resistance; and ‘Tandem’ (k‑30883, Russia), ‘Novichok’ (k‑30806, Russia), etc. for soil stress resistance. Besides, cvs. ‘Ekolog’ (k‑29417, Russia), ‘Conrad’ (k‑30406, USA), etc. were identified as promising for cellular breeding. General principles regulating selection of initial genotypes for barley tissue culture were formulated. Of practical interest is application of cell-level breeding techniques to cultivars sensitive or moderately resistant to stressors. Accessions from VIR’s collection have been used to develop spring barley cultivars adapted to the cultivation conditions of the Volga-Vyatka region: more than 30 cultivars through hybridization and selection, and 6 cultivars with theuse of in vitro tissue culture.

Background. Studying the intraspecies diversity of fruit crop wild relatives is one of the leading trends in botanical and genetic resource research associated with identification and utilization of the phenotypic potential of the population and species, the initial stage in plant breeding and introduction processes, and a prerequisite to solving a number of problems posed by the theory of microevolution, biosystematics and population biology. Currently, large tracts of wild apricot populations (Prunus armeniaca L. = Armeniaca vulgaris Lam.) have been preserved in Central Asia, China and Dagestan. The natural populations of apricot in the Mountainous Dagestan are spread along the valleys of the Avar Koysu, Andi Koysu, Kazikumukh Koysu and Kara Koysu rivers, at altitudes of 350–1500 m ASL, and (sporadically) over the southern slopes – up to 1900 m ASL. They prefer crushed limestone hillsides, where they form the so-called ‘apricot savannah’, rarely assembling into dense massifs. With this in mind, it seems theoretically and practically interesting to evaluate various forms in the diversity of natural apricot populations in the Mountainous Dagestan, with qualitative traits of their endocarp (stone) as a target.

Materials and methods. To analyze the diversity of endocarp (stone) forms in natural apricot populations under the conditions of the Mountainous Dagestan, three model cenopopulations (CPs) were selected: in Gunibsky District, along the Kara Koysu (Lower Keger Vlg., 900–1200 m ASL) and Bagdakuli rivers (Salta Vlg., 900–1100 m ASL), and in Levashinsky District, along the Kazikumukh Koysu river (Burtanimakhi Vlg., 1000–1200 m ASL). Stones were collected along the slopes by using transect itineraries. Morphological description of endocarps was made for 328 trees according to 11 qualitative features by standard techniques.

Results. A comparative analysis of natural apricot populations showed high variation in the size and shape of the endocarp. Five classes were identified for stone size; of these, the very small (37.8%) and small (37.5%) types had the highest percentage. There were seven types of the endocarp’s shape (rounded, ellipsoid, ovoid, oblong, prolate, teardrop-shaped, and semicordate). Ovoid or rounded shape was observed in an overwhelming majority of apricot trees: their share was 65.3% of the total diversity. Correlation analysis of the endocarp’s features revealed credible positive correlations between the traits (1) ‘keel height’ and ‘rib width’, and (2) ‘lateral rib type’ and ‘rib width’. Creditable negative correlations were found for the trait ‘keel pattern’ with ‘lateral rib type’ and ‘keel height’.

Background. In breeding work, it is necessary to take into account such an important feature as male sterility of the hybrids obtained. If a plant has visually visible anthers and pollen, the quality of the pollen grains themselves may be low. It is necessary to carry out not only a visual analysis, but also a cytological study of pollen in order to properly assess the reproductive potential of plants.

Materials and methods. Wild species, some cultivars, lines and hybrids of sunflower from the collection of the N. I. Vavilov All-Russian Institute of Plant Genetic Resources were taken as objects of research. The plants were grown on the fields of Kuban Experiment Station. Pollen was collected from preinsulated inflorescences, fixed in FAA solution and stained with acetocarmine. The ratio of fertile pollen grains to the total number of pollen grains (in %) was calculated, the diameter of the pollen grains was measured, and variability curves were drawn.

Results. Mature pollen grains in sunflower are rounded, tricolpate-poral, threecelled; the average pollen diameter in cultivated sunflower is 28–32 μm; in wild species, the range is from 20– 22 μm to 32–34 μm. All accessions were divided into three groups. Fertile: high level of fertility (75–99%) and low morphological heterogeneity of pollen; the variation curve for the average diameter was characterized by one distinct peak. Most of the studied accessions were included here: cultivars, most of the lines and some of the wild species. Semi-fertile: the number of well-stained pollen grains is below 75%; there are differences in the degree of staining and size of the pollen; the variation curve had additional peaks. This group included some of the lines, hybrids and wild species. The greatest morphological heterogeneity was observed in the group of perennial interspecific hybrids. Sterile: pollen grains were absent or were observed very sporadically.

Conclusion. To assess the fertility of plants, it is important not only to determine the degree of staining in pollen grains, but also to rank them by diameter and construct variation curves to reveal morphological heterogeneity of pollen.

Background. The formation of cover tissues (epidermis, cork), providing a connection with the environment, in the evolution of flowering plants was one of the main consequences of the transition to life on earth. The epidermis, which emerged as a device for protecting deeper underlying tissues from drying, subsequently acquired additional functions (participation in gas exchange and transpiration, absorption and isolation of certain substances as well as protection from the penetration of pathogens) and became a multifunctional tissue consisting of several types of cells (basic, stomatal, and trichomes). Features of the fine structure of the epidermis are of interest in representatives of the subfamily Maloideae Werber (Rosaceae Juss.), which grow, inter alia in mountain agrobiocenoses with their rather harsh conditions. They extended their area of distribution to various habitats due to the development of structural adaptations that play an important role in the formation of resistance to stressors of different etiologies.

Objective. Representatives of 4 genera were chosen as model objects from subfam. Maloideae for the study: Malus domestica Borkh., Pyrus communis L., Cydonia oblonga Mill., and Mespilus germanica L.

Materials and methods. Mature leaves and fruits were selected from the middle part of the crown of three model trees of each species. The samples were studied by scanning electron microscopy (SEM), with a freezing attachment.

Results. Leaves of Maloideae were found to be hypostomatic, while the abaxial (lower) epidermis is multifunctional: it performs a barrier function together with the cuticle. Formation of the cuticular nature can be attributed to the surface structures: peristomatic rings and ridges as well as radially extending folds, all forming a specific microrelief. The adaxial (upper) and abaxial surfaces clearly differ not only in the features of the structure, but also in the specificity of the microrelief’s arrangement. Species-specific traits were also found in the structure of the surface tissue of the pericarp. M. germanica, unlike the other species, does not have a continuous cuticular cover and wax deposits: most of a mature fruit’s surface is covered with a peeling cork layer. In the study of the surface of C. oblonga fruits, numerous rather large stomata with peristomatic rings and cuticular cushions were found similar to those in leaves.

Conclusion. Surface structures of leaves and fruits in subfam. Maloideae include formations of cuticular nature, with different specificities of microrelief shaping due to the functional load of the epidermal tissue and environmental conditions. They can also be involved in building resistance to biotic stressors. The obtained data on the features of the fine structure of surface tissues are of interest for applied and theoretical studies, especially environmental and botanical, relating to taxonomic issues.

Average buckwheat yield in Russia has increased from 0.49 to 0.94 t/ha (1.9 times) in the period from the 1960s to 2011-2017, which is comparable to the growth of wheat yields for the same period (2.1 times, from 1.18 to 2.42 t/ha). However, if the growth in wheat yields occurred gradually, the entire growth of buckwheat yield falls on the beginning of the 21st century. Such differences in dynamics indicate that the increase in buckwheat yield is not related to the improvements in agricultural technology or climate changes. Nor it is related to any significant changes in the structure of buckwheat sowing regions, as the average yield in the most important region of buckwheat cultivation, Altai Territory, is only 0.91 t/ha (i. e. less than the country’s average). Chronologically, the period of an abrupt increase in the yield of buckwheat in Russia coincides with widespread introduction of cultivars with determinate growth habit (determinants). Since 1999, the share of determinant varieties in the total area under buckwheat in Russia has increased from 8.2 to 56.7%. Apparently, it was a main cause for the significant growth of buckwheat yield in Russia. Determinant cultivars based on the d (det) mutation are characterized by reduced plant height, reduced number of flowers on shoots, and more intensive and fast blossoming of inflorescences (and, consequently, more intensive and fast maturation). The increased morphological potential of productivity (the number of vegetative nodes on the stem and first – order branches) ensures a higher level of yield for these cultivars. At present, our lab is developing determinant buckwheat cultivars using some additional mutations. A major success in this work has been the world’s first determinant cultivar with green flowers (the gc mutation) named ‘Design’, which develops thicker and stronger fruit stalks with higher resistance to seed shattering.