The article presents the results of the analysis of amino acid composition of grain of spring soft and durum wheat varieties by the amount of proline and essential amino acids under conditions of favorable and dry years in terms of weather factors. An increase in the amount of proline was established under conditions of temperature stress and a lack of moisture in soil, it allows us to consider this fact as an index of resistance to unfavorable environmental factors. The amount of essential amino acids depended on weather and technological factors. The content of the amino acid proline in spring wheat grain should be considered as a signaling function for stressful vegetation conditions. The content of essential amino acids in spring wheat grain increases in favorable years and against the background of moldboard plowing.

The heterogeneity of grain quality can lead to limited predictability of qualitative and quantitative characteristics of the wheat yield, especially with an increase in the importance of drought and salinity caused by climate change. This study was undertaken with the aim of creating basic tools for phenotyping and assessing the sensitivity of genotypes to salt effects at the level of some wheat kernel attributes. The study considers 36 variants of the experiment, including four wheat cultivars—Zolotaya, Ulyanovskaya 105, Orenburgskaya 10, Orenburgskaya 23; three treatment variants—control (without salt) and two salts exposure (NaCl at a concentration of 1.1 g L⁻¹ and Na₂SO₄ at a concentration of 0.4 g L⁻¹); as well as three options for the arrangement of kernels in a simple spikelet—left, middle, and right. It has been established that the salt exposure had a positive effect on the percentage of kernel fulfilling in the cultivars Zolotaya, Ulyanovskaya 105, and Orenburgskaya 23 compared to control. The kernels of the Orenburgskaya 10 variety matured better in the experiment with Na₂SO₄ exposure, while the control variant and NaCl gave the same effect. When exposed to NaCl, significantly greater values of weight, transverse section area, and transverse section perimeter of the kernel were noted in the cv Zolotaya and Ulyanovskaya 105. Cv Orenburgskaya 10 responded positively to the use of Na₂SO₄. This salt caused an increase in the area, length, and width of the kernel. The fluctuating asymmetry of the left, middle, and right kernels in the spikelet was calculated. In the cv Orenburgskaya 23 the salts affected only the kernel perimeter among parameters examined. The indicators of the general (fluctuating) asymmetry were lower in the experiments with the use of salts, i.e., kernels were more symmetrical than in the control variant, both for the cultivar as a whole and when compared taking into account the kernel location in spikelet. However, this result was unexpected, since salt stress inhibited a number of morphological parameters: the number and average length of embryonic, adventitious, and nodal roots, flag leaf area, plant height, dry biomass accumulation, and plant productivity indicators. The study showed that low concentrations of salts can positively affect the fulfilling of kernels (the absence of a cavity inside the kernel) and the symmetry of the left and right sides of the kernel.

The article is devoted to studying the influence of various treatment options for spring wheat seeds with biohumus and growth regulators. The results of field experiments led to the establishment of the effect of various seed treatment options on the content of chlorophyll, carotenoids and antioxidant enzymes, spike productivity indicators, grain quality indicators (nature, vitreous, raw gluten content). A positive effect of the studied preparations on the increase in the content of photosynthetic pigments, catalase, as well as the number of grains in an ear and the weight of grain per ear was established.

The use of instrumental methods of analysis in the assessment of indices that record changes in symmetry in the structure of grains to evaluate the quality of durum and soft wheat grain is currently considered a search tool that will allow us to obtain previously unavailable data by finding correlations associated with differences in the shape and ratio of starch granules in conditionally symmetrical and asymmetrical wheat fruits (kernels) formed in different field conditions and with different genotypes. Indicators that had previously shown their effectiveness were used to analyze the obviously complex unique material obtained as a result of growing under critically unique sowing conditions in 2022, which affected the stability of grain development and filling. For the evaluation, a typical agronomic comparative experiment was chosen, which was used to evaluate the soil tillage practices (fallow, non-moldboard loosening, and plowing) and sowing dates (early and after excessive rainfalls), which made it possible to analyze a wider range of factors influencing the studied indices. The soil tillage methods were found to affect the uniformity of kernel fullness and their symmetry, and the sowing dates did not lead to significant differences. This study presents detailed changes in the shape of the middle cut of a wheat kernel, associated with assessing the efficiency of kernel filling and the symmetrical distribution of storage substances under the influence of external and internal physical factors that affect the formation of the wheat kernel. The data obtained may be of interest to breeders and developers of predictive phenotyping programs for cereal grain and seeds of other crops, as well as plant physiologists.

The article contains an analysis of the prevalence of spring durum wheat crops in the world and in the Orenburg region, and yields over a long period. There is a tendency to decrease the productivity of this crop over the studied period, primarily due to the increasing aridity of the growing season. The results of a correlation and regression analysis of the dependence of its yield on the main weather indicators are presented, while identifying their optimal values for the formation of highly productive crops of this crop. Analyzing the obtained dependencies, attention is focused on the intensity of the growing conditions of spring durum wheat in recent years in the arid zone, which do not allow realizing the potential of this crop. The calculated coefficients of the relationship between the yield of this crop and weather factors show reliable dependences on the temperature regime of May, July, the amount of precipitation in May and the relative humidity of the entire growing season. The results of the mathematical dependence of durum wheat grain quality indicators on the weather characteristics of the growing season are presented. At the same time, the optimal air temperature values in May were 13.4 °C, in June 15.0 °C, in July 23.3 °C, according to the amount of precipitation, the optimal amount for the months of vegetation was 30 mm in May and June and 36 mm in July. The above–mentioned optimal values of weather factors in May corresponded to the theoretical yield of durum wheat up to 30.0 c from 1 ha, the optimal values in June - 22.6 c from 1 ha and the optimal values in July – 18.9 c from 1 ha. Correlation coefficients and actual data on grain quality indicators allow us to note their significant variability from the conditions of the growing season and varietal specificity. A high correlation (r = 0,827-0,926) was established for the studied grain quality indicators with average relative humidity and with an average daily humidity deficit. The average relationship (r = 0.635-0.745) was obtained for the average air temperature, maximum air temperature and average daily humidity deficit. Grain quality is subject to variability from the conditions of the growing season: in harvest years, there is an increase in the vitreous content of grain to 92-93%, and in years with an increase in the temperature regime of the air, there is an improvement in the quality of gluten to the level of class II.