The purpose of this research by the way of investigating the molecular genetic structure of a highly variable fungal phytopathogen Pyricularia oryzae Cav., to determine effective genes for the development of a strategy for immunogenetic protection against rice blast in conditions of epiphytotic development of the disease in the south of Russia, which would combine high efficacy with both environmental friendliness and resource and energy saving, to ensure country's food security. The knowledge of local pathotype diversity of Pyricularia oryzae Cav. and the (a)virulence genes in rice-growing regions of Russia may allow the prediction of new races and its interaction in local agro-ecology. The identification of virulence gene may become an indispensable theoretical basis for the development of genetic sources with long-lasting resistance to rice blast. Based on molecular and genetic approaches, the genetic structure and biodiversity of the phytopathogenic fungus Pyricularia oryzae Cav. in the south of Russia were considered. The monitoring was studied and it isolated 57 strains of the pathogen from the damaged herbal material collected from the fields in eight agro-ecological rice-growing regions of the Krasnodar Region (Russian Federation): Krasnoarmeysky, Kalininsky, Krymsky, Abinsky, Temryuksky, Seversky, Slavyansky districts, Krasnodar, Rostov Region (Russian Federation)-Proletarsky district and the Republic of Adygea (Russian Federation). A multiplex PCR technique was applied on the basis of fragment analysis to identify the virulent fungal isolates. 33 fungal genotypes with unique genetic profiles were identified among the studied races of Pyricularia oryzae Cav. Their DNA profiles were created. The studied isolates of the pathogen of rice blast were classified using morphological and microbiology cultural features. Based on the phytopathological test using differentiation rice varieties, the quantitative and qualitative composition of (a)virulence genes in fungal races was established. Effective genes for pathogen resistance, which are recommended for breeding programs for the development of rice varieties resistant to rice blast, were identified in the south of Russia.

The present work is devoted to investigation of the possibility to apply methods of Marker-Assisted Selection (MAS) to introgression the SalTol QTL into genotypes of elite Russian varieties of rice. It was shown that microsatellite markers Rm493, may be effectively used to control transfer the SalTol QTL genes into Russian populations of rice. Based on the highly productive variety "Novator", we obtained the lines Nov-129 and Nov-148 carrying loci SalTol in homozygous state. The lines Nov-129 and Nov-148 are used as an improved salt tolerance donor source to obtain hybrids tolerance to salinity.

Rice (Oryza sativa L.) plants were subjected to NaCl stress within 35 days. The shoot dry weight, root dry weight, total survival percentage and contents of inorganic ions in dry samples of stressed plants were measured to identify the physiological adaptive mechanisms by which rice plants at vegetative stage tolerate salt stresses. Laboratory testing of the 10 rice cultivars showed that the salt concentration for the treatment is especially significant for assessment of the relationship between ion accumulation and salt tolerance. Salt treatment strongly stimulated accumulations of Na + , Na + /K + ratio, Clin shoot and root and reduced K + , NO 3 contents in both organs under 1.2% NaCl stress condition, but not always under 0.6% NaCl concentration. It was shown significantly negative correlation (p<0.5) between the Na + content and dry weight of shoot and root under 1.2% NaCl stress condition. Also, was founded significantly negative impact (p<0.5) of Clions on biomass growth and survival rice plants and positive relationship (p<0.5) among the root dry weight and K + , NO 3 content under the high NaCl concentration (1.2% NaCl). So, in addition to Na + , the contributions of Clto abiotic stresses of rice should not be ignored.

Selection done using molecular markers has spread to all types of agricultural plants and animals. Marker assisted selection (MAS) is safe for ecology and food products consumed. The purpose of the study is to develop Sub1A gene (which determines tolerance to prolonged flooding) in the Russian rice varieties using DNA-markers and Polymerase chain reaction (PCR) analysis. A large volume of prebreeding rice material (F2-F4, BC2F2) was created with tolerance genes for prolonged flooding, to control weed in rice agrophytocenosis. The forms with 120-130-day vegetation period were selected. An analysis of the co-inheritance of simple sequence repeat (SSR) markers Sub1Aq, Sub1C173, Sub1A203 with the Sub1 gene was carried out. It revealed the codominance of the selected microsatellites. They can be used to identify and visualize the allelic state of a given target gene in the breeding material. The recurrent parental rice forms, donors of the gene Sub 1 and the hybrids of F2 and ВС2F1 population were tested on tolerance to prolonged flooding. The gene is effective in ensuring resistance to this stress factor within 2 to 3 weeks and it can be recommended for the breeding programs to develop modern genetic resources of rice tolerant to prolonged and deep flooding for weed control on rice fields.

The correlation between the traits allows making an indirect selection, while the selection according to one trait results in the selection of another indicator. The purpose of the work is to estimate the variability of quantitative traits of Sudan grass and the correlations between them, to identify marker traits of high productivity and quality of green mass. There have been presented the study results of 115 collection samples of Sudan grass with various environmental and geographical origin of the Rostov region made in 2014-2018. There was a great variability (V=29.7-50.0%) in tillering, leaf square, green mass yield, stem diameter, plant height among the studied varieties.  The percentage of fiber and nitrogen-free extractive substances in the green mass of the studied Sudanese grass samples were characterized with high stability (V = 4.9-5.0%). The analysis has identified a strong correlation between green mass productivity and leaf length (r=0.59±0.01), leaf width (r=0.57±0.02), leaf square (r=0.54±0.03), plant height (r=0.48±0.06), length of ‘vegetation-ear formation’ period (r=0.48±0.004) and number of leaves (r=0.42±0.03). There has been identified a group of samples ‘Boldinsky’, ‘Fioros’, ‘К-176’, ‘К-205, ‘К-272’ with 35-55 t/ha green mass productivity and with 20.5-24.5% dry matter in green mass. The conducted analysis has shown that dry matter percentage greatly correlates with plant height (r=0.30±0.001), vegetation period (r=0.34±0.004) and number of leaves (r=0.26±0.006). The markers of high productivity and quality of green mass are length of a vegetation period and number of leaves (their increase results in the growth of green mass yields), dry matter percentage in green mass and protein decrease in it.

The article summarizes the study results of adaptability parameters of winter durum wheat depending on its forecrop. The study was carried out in the Rostov region in 2015-2017. As the objects of the study there have been used 8 winter durum wheat varieties ‘Donchanka’, ‘Amazonka’, ‘Agat Donskoy’, ‘Kristella’, ‘Lazurit’, ‘Oniks’, ‘Diona’ and ‘Eyrena’. The variety ‘Donchanka’ was taken as a standard variety. In the field trials the varieties were sown after weedfree and green fallows, and after such forecrops as peas, sunflower and maize for grain. The obtained data showed that green fallow was the most favorable forecrop for winter durum wheat, an average yield of which was 7.69 t/ha. When sown after various forecrops, all varieties had different adaptability parameters. The best forecrops were weedfree fallow (‘Kristella’ with 7.78 t/ha, ‘Lazurite’ with 7.74 t/ha), green fallow (‘Agat Donskoy’ with 8.30 t/ha, ‘Lazurit’ with 8.46 t/ha) and peas (‘Oniks’ with 7.41 t/ha, ‘Diona’ with 8.11 t/ha). Among the whole set of the varieties, the variety ‘Agat Donskoy’ (bi>1) proved to be the most highly responsive, while maintaining in most cases high stable yields (si2 <1), productivity of the varieties sown after all forecrops, except sunflower, was 6.93-8.30 t/ha. With productivity increase of 1 t/ha, it improved its indicator (bi) by 1.16-5.15 t/ha. The variety ‘Eyrena’ is recommended for cultivation on an extensive background, since through the years of study it turned out to be the least responsive - with productivity increase by 1 t/ha, it improved its indicator (bi) by 0.01-0.55 t/ha after such forecrops as peas, sunflower and maize for silage.

The high yield potential of winter wheats cannot be realized due to disease pressure under field conditions. One of the most harmful of such diseases is stem rust, hence the constant search for sources of resistance and the development of new varieties resistant to stem rust is of great relevance. This study deals with the identification of stem rust resistance genes in a collection of winter wheats grown in Southern Russia. This genepool has not been studied yet. A total of 620 samples of winter soft wheat from various ecological and geographical zones were tested under field conditions. To identify the specific genes or alleles responsible for resistance, all samples were genotyped using PCR. As a result, the groups of resistant samples, carrying the Sr2, Sr31, Sr38 and Sr44 genes in various combinations, were identified. Most of the stem rust resistance was provided by the presence of the effective Sr44 gene. This information can be used in the future breeding work for stem rust resistance.

The purpose of research is to determine how force of grain binding with the ear of winter wheat depend on properties of grain, its stage of ripeness and weather conditions. Objects of research is to consider dependences and regularities of changes in force of grain binding with an ear of winter wheat due to its temperature and humidity, duration of plant growing (standing) upon reaching full ripeness, ambient temperature and to assess the possibility of their use to control threshing process. Field experiments were carried out to determine force of grain binding with the ear of winter wheat of variety “Admiral”, its temperature and humidity, ambient temperature, duration of plant growing (standing) after reaching full ripeness over the recommended agro-harvesting period. On the example of graphic dependence of parameters under discussion for the studied variety on duration of plant growing (standing) over the period of experiments we revealed the tendency of their change. Type and closeness of binding were assessed according to correlation and regression analysis. It is established that the correlation between force of grain binding with the ear of winter wheat and independent variables is linear. The analysis of regression equation parameters: overall coefficients of correlation, determination, values of the Fisher criterion, significance level, as well as the Durbin-Watson criterion ensured that the chosen model is adequate and can be applied in practice to control threshing process.