The approaches of modern plant biology, biochemistry and biotechnology are
aggregately targeted at the improvement of health and life quality of the
population. It is achieved through the enhancement of qualitative
characteristics in various crop genotypes, the composition and content of
bioactive compounds (BAC) in them, and their adaptability to stressors. An
important trend is the development of rapid plant breeding technologies for
cereal, vegetable, fruit and berry crops beneficial for healthy nutrition.
This issue presents the results of versatile experimental and theoretical
research ventures contributing in different ways to the effective promotion
of this trend.

Background. Oat (Avena sativa L.) is one of the most important sources of protein, oil, starch and dietary fibers, in particular β-glucans. Dietary fiber serves as a source of nutrition for the intestinal microflora and significantly affects not only its composition, but also the normal functioning of the intestine as a whole. In connection with the increased interest in β-glucans as a food component and dietary supplement, there is a need in a convenient and inexpensive method for determination of β-glucans content in grain. The article provides an overview of the existing methods for the isolation and determination of soluble β-glucans in cereals: enzymatic, alkaline, alkaline-enzymatic, colorimetric; their advantages and disadvantages are noted. The main disadvantages of some methods are the complexity and duration of execution, significant cost of the required reagents, and the inability to determine the exact content of β-glucans due to their insufficient purification from various impurities.

Results. This study used the example of naked and covered oat cultivars to demonstrate applicability of the gravimetric method that we developed by modifying the alkaline method. Whole grain oat flour was pretreated with a 50% ethanol solution to inactivate β-glucanase and remove free sugars, some lipids, proteins, and other substances. β-glucans were released from the aleurone layer and the endosperm with a 5% sodium hydroxide solution, and finally extracted with a 70% ethanol solution. Β-glucans floated to the surface in the form of a bunch of fibers, which was then dried at a temperature about 100-102°C to constant weight and weighed. The content of β-glucans was calculated from the dry weight (%). The isolated β-glucans were checked for the presence of accompanying substances: the content of nitrogenous substances was determined by the Kjeldahl method, and the presence of starch was determined by a qualitative reaction with Lugolʼs reagent.

Conclusions. The content of β-glucans in the grain of the studied samples ranged from 3.12±0.18 up to 4.65±0.17% of the dry weight. As a result of the study, the optimal conditions of β-glucans isolation were selected: the extraction mixtures ratios, as well as the modes of centrifugation, sedimentation and drying were established. It has been shown that this method makes it possible to isolate β-glucans with a minimum impurity of nitrogenous substances (0.07-0.12%) and no traces of starch. One of the advantages of the described method is its availability for mass analysis when studying a collection of grain crops.

For raspberries (Rubus idaeus Focke), one of the most valuable and popular berry crops in Russia, it is important to study the genotypeenvironment interaction. The complex genomic composition of modern varieties of this crop, the modifying influence of climatic growing conditions on the manifestation of variable traits that affect the marketable fruit yield, necessitate an assessment of the varieties available in the collection in order to identify the most optimal ones for specific agrobiological conditions of the region chosen for crop cultivation. During a three-year (2017-2019) study of ten accessions of perpetual and semi- perpetual raspberries of domestic and foreign breeding accumulated at the Krymsk EBS, a branch of VIR, biological features of the phenophases of raspberries seasonal growth and development were observed concerning the following characters: the number of berries; average, minimum and maximum berry weight, as well as the total and marketable yield. The purpose of this work was to select high-tech varieties of perpetual raspberries for commercial plantations in the North Caucasus region of Russia by selecting the optimal ones with a complex of economically important traits, from those available in the VIR collection of plant genetic resources. A quantitative assessment of the influence of the variety genotype, of the conditions of the year of cultivation and their combined effect on the studied characters was carried out using the two-factor analysis of variance. It was shown that varietal characters have the greatest effect on the commercial productivity of the bush (the share of the “variety” factor influence is 68%), while weather conditions influence it to a lesser extent (the share of the “year” factor influence is 7.5%). Generalization and complex analysis of the data obtained in the course of this work showed that a combination of economically important traits was exhibited by the studied varieties ʻBryanskoe Divoʼ, ʻHerculesʼ, ʻNikaʼ and ʻAnteyʼ, which can be recommended for large-scale production trials. The use of the rapid clonal micropropagation of raspberries of perpetual fruiting type makes it possible to obtain a sufficient number of plantlets for laying out industrial variety trials for one to two years after the introduction into the culture, which, as a result, accelerates the introduction of new varieties into production.

The breeders are faced with the task of the fastest breeding of sour cherry (Prunus cerasus L) varieties, which will be able to fill a niche among the insurance stone fruit crops, complementing the existing assortment. It is practically impossible to speed up this process without the use of in vitro culture. In this regard, the purpose of the present study was to identify the most favorable timing for isolating embryos of sour cherry varieties and hybrids with sweet cherry for embryos active development and growth in vitro. Analysis of the literature data and the results obtained in this study allows a conclusion that the timing of embryos isolation for their introduction into in vitro culture plays a very important role for the entire breeding process. Due to the discrepancy in defining the timing, a certain starting point is proposed, which is the date of fertilization (artificial pollination), or mass flowering in the case of free pollination. The parameters (height and width) of sour cherry seeds, which depend on the period of pollination, are given. Together with the cotyledons, the embryos of sour cherry varieties on the 14th day of their development correspond to sizes from 1.2 × 0.4 mm to 1.6 × 1.0 mm and, in the case of normal fertilization, increase in size from 6 .5 × 5.1 mm to 7.2 × 6.3 mm by day 28-30, on an average. At the same time, the seed with the embryo of hybrid sour cherry varieties (dukes) reaches higher values, e.g., 11.3 × 8.1 mm. When introducing cherry embryos into culture, one should focus on their size, as well as on the period that has passed from pollination. It was found that the periods of isolation, both early on day 14-19 and late on day 44-52, negatively affect the development of embryos: they stop their development, and the number of the obtained seedlings decreases. It has been experimentally proven that the most optimal timing of fruit picking for growing cherry hybrids in vitro is the period from day 28 to 32 after pollination of flowers: active development was observed in them on days 10-15 in test tubes, and most of them (83-85%) began to germinate 40 days later (on day 39-47 after the introduction into in vitro culture). In general, this leads to the efficient hybridization and accelerated obtaining of seedlings in the same year.

Agrobacterium rhizogenes Conn is a soil bacterium, which can transform plants by inserting a plasmid fragment into the plant genome. This fragment contains a “root locus”: four genes that cause root overgrowth of the transformed plant, the so-called “hairy root syndrome”. The most studied gene of the root locus is rolC. For more than 30 years of research on this gene, data have been obtained on its expression, protein localization and putative functions of the protein as well as on its effect on plant morphology and biochemistry. The rolC transformation leads to multiple morphological effects, most common among which are dwarfism, bushiness, and a change in the shape of the leaf blade. Such specific plant reactions are associated with changes in hormone balance under the influence of rolC. The levels of auxins, cytokinins, and abscisic acid do change in transformed plants, but no regularities have been revealed. Also, the signaling pathways of rolC affecting the hormonal system of plants are not established. Morphogenetic effects can occur in varying degrees depending on the promoter under which the rolC works. A constitutive promoter usually leads to a more pronounced effect when compared to a gene that operates under a native promoter. Secondary plant metabolism is also affected by rolC. The synthesis of various metabolites is amplified in transformants, and, in contrast to morphological effects, this biochemical effect does not depend on the promoter. Some secondary metabolites are associated with the plant defense system; thus, rolC is able to indirectly influence this aspect of plant physiology. This review summarizes the results of the rolC gene studies in plants. The authors formulate the main hypotheses regarding the mechanisms of the gene in order to promote our understanding of its function in plants.