Rossijskaâ selʹskohozâjstvennaâ nauka

The purpose of the study is to identify the relationship between drought resistance indicators and the yield of potato plants under unfavorable conditions. A xeromorphic leaf structure is considered a diagnostic sign of plant drought resistance. The objects of the study were 24 potato varieties. Planting of seed, pre-planting tillage, harvesting and crop recording were carried out in the period 2020-2022 on the territory of the Samara Research Institute of Agriculture - a branch of the Samara Scientific Center of the Russian Academy of Sciences. Growing conditions for 2021 and 2022 characterized by elevated temperatures and insufficient moisture. The number and size of stomata per unit leaf area were chosen as the criterion for xeromorphism. The studied varieties were divided into two groups (n=12 each) according to the number of stomata. In the first group, the average number of stomata was 26 thousand pcs./cm2 of leaf, and in the second group - 35 thousand pcs. (F=41, p=0.03). More developed structural features of xeromorphism and the accumulation of certain types of metabolites in the second group of varieties led to a 1.6 times greater yield than in the first less xeromorphic group (F=9, p=0.004). The second group was characterized by a large number of mesophyll cells per unit leaf area (584 thousand pieces/cm2 versus 557 thousand pieces), a high content of phospholipids (36 mg/g dry weight versus 31 mg/g), dry weight (0.19 vs. 0.17 g/g wet weight) and the ratio of membrane lipids to membrane proteins (1.4 vs. 1.2). In the less xeromorphic group of plants, the level of oxidative stress, assessed by LPO products, was 0.050 µM/g fresh weight and was 12 % higher than in the more xeromorphic group (F=6, p=0.08). The revealed positive correlation between yield and xeromorphic genotypes indicates the prospects of using this criterion in potato breeding or creating a variety model.

In order to assess the stress resistance of genotypes, we studied the influence of soil stressors on the content of polyphenolic substances in grain, straw, and roots of barley (Hordeum vulgare L.) of various varieties with differentiation by origin (domestic and foreign selection) and methods of production (hybridization and cell selection). The plants were grown in vegetative tanks with sod-podzolic soil in natural conditions until the seeds ripened. The experimental design included the following options: with excess cadmium (Cd2+ 6.4 mg/kg); increased acidity (pHKCl=4.8); simulated drought in the interphase period, emergence into the tube - earing; without stress load at pHKCl=6.5 (control). The content of polyphenols in terms of gallic acid was determined by the spectrophotometric method. The total accumulation of polyphenols in grain under drought conditions (9.18…11.13 mg/g) and in the presence of excess Cd2+ in the soil (9.07…9.10 mg/g) exceeded the control by 2.5…14.8 % and 2.8…8.5 %, respectively. On acidic soil, compared with the control, the amount of polyphenols in grain significantly decreased in all domestically bred barley varieties that underwent selection on acidic soils or selection on acidic selective media in vitro, in Vitrum - by 16.1 %, Rodnik Prikamye - by 11.8 %. In varieties of foreign selection (Zazersky 85, Triumph and Tallon), under acidic conditions, the value of this indicator, on the contrary, increased by 2.2…4.8 %. Most of the polyphenols were in a bound state. The distribution of free fraction polyphenols among organs (% of the total amount in the plant) was revealed: straw (41.4…49.1) > roots (32.4…42.5) > grain (15.6…22.6). Among the stressors studied, increased acidity contributed to a greater extent to the increase in the relative accumulation of free polyphenols and most significantly in the roots - in varieties and regenerants of the selection of the Federal Agrarian Research Center of the North--East by 19.0 %; foreign selection - by 35.7 %.

The purpose of the research is to assess the influence of photosynthetic activity of the new promising oat variety Irtysh 33 on the formation of its yield and quality of green mass. The experiments were performed in 2017-2022. The soil of the experimental plots is ordinary leached chernozem with a humus content of 5.7…7.5 %. The experiment was carried out in 4 repetitions. The seeding rate is 4 million viable seeds/ha. The area of the plots is 10 m2. The object of research is a new promising oat variety Irtysh 33, the standard variety is Orion. Optimal moisture supply was observed in 2019 (hydrothermal coefficient = 1.10), excess moisture in 2018 (hydrothermal coefficient = 1.39), and dry conditions in 2017, 2020-2022. (hydrothermal coefficient = 0.58-0.77). On average, over the period of research, the variety Irtysh 33 was characterized by a more developed leaf apparatus (35.5 and 24.9 % higher than the standard for leaf surface area in the sweeping and flowering phases, respectively). The new variety was characterized by an increased mass fraction of dry biomass, exceeding the Orion standard by 14.6 % in the heading phase and by 10.2 % in the flowering phase. The Irtysh 33 variety provided photosynthetic potential 30 % higher than the standard. The new variety generated forage yields that were 7.3 and 3.2 t/ha higher than the standard in the heading and flowering phases, respectively. An increased quality of forage mass of the Irtysh 33 variety in the heading phase was also noted - higher than the standard for the mass fraction of protein by 0.4 %, for protein collection by 1.07 t/ha and 0.7 % lower than the standard for the mass fraction of fiber. Indicators of photosynthetic activity had a direct impact on the formation of the yield and quality of green mass of the Irtysh 33 variety, depending on the development phase. From spawning to flowering, the role of accumulation of dry biomass on the formation of the mass fraction of fiber (from r=0.515±0.02 to r=0.684±0.103, respectively) and yield (from r=0.479±0.008 to r=0.602±0.015) increased, as well as the role of net productivity of photosynthesis (for the accumulation of dry biomass from r=0.115±0.004 to r=0.419±0.017; for yield from r=0.460±0.020 to r=0.601±0.051). The average direct degree of conjugation of the assimilation surface of the leaf with the mass fraction of protein, noted in the sweeping phase (r=0.640±0.19), in the next phase changed to the average reverse (r= -0.508±0.021).

The research was carried to study the effect of fungicides of various classes on the intrapopulation structure of Pyrenophora teres in terms of sensitivity to toxicants, virulence and racial composition. The work was performed using eight treatment options in different doses (control without fungicide, 25 %, 50 %, 75 %, 100 % (the norm), 125 %, 150 %, 175 %, 200 %) fungicides Magnello, EC (1 l/ha), Capella, M (1 l/ha), Kolosal Pro, MC (0.4 l/ha), Quadris, SC (1.2 l/ha), Amistar Trio, EC (1 l/ha), Orgamika C, L (0.4 l/ha) of plants and introduction to a nutrient medium with a pure culture of P. teres. The racial composition of the populations was determined using an international set of differentiator varieties. When treating plants with fungicides with the norm allowed for use in agriculture, the minimum efficiency values were found in the preparations Quadris, SC (52.3 %), Orgamika C, L (66.8 %), the maximum - Magnello, EC (88.2 %) and Kolosal Pro, MC (97.0 %). The average virulence of the population isolated after Quadris, SC treatment was revealed to be maximum - 3.4 points (at the control level). The greatest racial diversity was found in P. teres populations isolated after treatment with fungicides based on triazoles Magnello, EC (CF=0.10) and strobilurines Quadris, SC (CF=0.10). The maximum intrapopulation heterogeneity was revealed in populations isolated after treatment with fungicides based on triazoles and Bacillus amyloliquefaciens: Kolosal Pro, MC (Sh=2.16), Capella, M (Sh=2.14), Magnello, EC (Sh=2.10)) and Orgamika C, L (Sh=2.12). When introducing the permitted rate of drugs into the pure culture of P. teres, on average, the growth of colonies slowed down from 86.1 % (Quadris, SC) to 100 % (Amistar Trio, EC). Preparations based on strobilurines and Bacillus amyloliquefaciens completely prevented sporulation. The results obtained allow us to conclude that there is a shift in sensitivity to the studied drugs.

Digital technologies are being actively introduced into Russian agriculture at different levels of information analysis (from the plot to the field, farm, region and country as a whole). In crop production at the field level, one of the most important values is the introduction of systems for accurate, rapid and automated monitoring of crop condition, the success of which largely predetermines the effectiveness of precision farming systems. The aim of the research is to develop a methodology for using Internet of Things technologies for non-contact monitoring of crops and related meteorological and soil-hydrological parameters. A wireless network is used as the basis for monitoring, which includes sensor nodes equipped with sensors for meteorological parameters, soil moisture and cameras equipped with a fish-eye lens. Sensor nodes equipped with sensors and cameras are placed in the field according to a specially designed scheme, individualized for each field. Development of the scheme of sensor placement on the field is based on the analysis of long-term archives of satellite data of high spatial resolution and refined soil maps of large scale. Information from sensors is wirelessly transmitted to the network coordinator (or base station) and then to the remote server in the database, and there it is automatically analyzed and interpolated for the whole field. Based on the analysis, recommendations for correction of agrotechnology of crop cultivation are formed. Elements of the methodology were tested on a number of test fields and showed high efficiency. Implementation of the proposed approaches can serve as an alternative to the use of remote sensing data for crop monitoring in offline precision farming systems.

The research was carried out to study the dynamics of the live weight of young cattle of the Kazakh white--headed and Hereford breeds (at birth, at weaning, at 12 months, adjusted for 210 and 365 days). An index assessment of live weight (at birth, weaning and at 12 months) was carried out for the formation of a breeding herd in basic farms. The index evaluation of the genetic breeding value by breeding characteristics was carried out using the best linear unbiased prediction (BLUP) method. The method of calculating the index score by statistical method with the construction of a genetic model of the animal has been worked out and the predicted indices of breeding value for 3 productive indicators have been calculated: live weight at birth, at weaning, at 12 months of age. In total, 9,503 farms for breeding Kazakh white--headed cattle and 2,766 farms for breeding Hereford cattle were analyzed. The accuracy of the evaluation of the breeding value index by the BLUP AM method is in cattle of the Kazakh white-headed breed: at birth 0.509-0.557 in bulls and 0.534-0.573 in heifers; at weaning 0.274-0.319 in bulls, 0.354-0.368 heifers; at 12 months 0.336-0.418 and 0.388-0.415, respectively. The accuracy of the evaluation of the breeding value index by the BLUP AM method is in Hereford cattle: at birth 0.531-0.810 in bulls and 0.511-0.565 in heifers; at weaning 0.330-0.608 in bulls, 0.257-0.366 heifers; at 12 months 0.386-0.498 and 0.342-0.414, respectively. The index estimation by the BLUP AM method makes it possible to increase the accuracy of the estimation of cattle of the Kazakh white--headed and Hereford breeds by live weight at birth, at weaning and one-year-old age.

The research aim is a correlation analysis of the PRM1, STK35 and IFT27 genes mRNA expression with the native and decryoconserved sperm quality indicators of Holstein bulls to search for effective transcriptomic biomarkers of bull semen. In the study course, native and decryoconserved sperm of seven Holstein bulls were used. To solve the study problems, eight indicators of sperm quality were studied, the studied genes in native and decryoconserved spermatozoa expression was analyzed in real time PCR. Nonparametric probabilistic and statistical methods were used, the analysis of rank correlation was carried out using Spearman’s criterion. Higher expression of the studied genes was mainly noted in frozen--thawed sperm compared to native. The mRNA expression level of the protamine gene (PRM1) did not give a reliable correlation with sperm parameters: The level ITF27 gene mRNA expression was significantly positively correlated with the content of defective cells from frozen--thawed sperm (0.714, p=0.05) and dead cells (0.714, p=0.0545) from native sperm. A negative correlation was noted with the content of normal cells in frozen--thawed sperm (-0.750, p=0.038) and live cells (-0.714, p=0.0545) in native sperm. The ITF27 gene transcript (mRNA) showed a negative correlation (-0.703, p=0.0545) in terms of the acrosome defect of frozen--thawed spermatozoa. In terms of the content of reactive oxygen species (ROS), the mRNA of the ITF27 gene had a significant positive correlation (0.786, p=0.0251). The STK35 gene transcript (mRNA) was the only one of all the studied mRNAs that had an average negative correlation with sperm motility in native (-0.692, p=0.052) and frozen--thawed sperm (-0.876, p=0.035). These studies can be used to create a system of non-invasive transcriptional markers of bull sperm quality.