The article deals with the results of the research on crop rotations with the concentration of cereals from 50 to 100 %. A comparative evaluation in respect of the yield from 1 hectare of land and planting is presented: feed units, digestible protein, grain as well as feed unit provision with protein. It’s established that an excess share of cereals in crop rotation doesn’t provide a significant grain yield increase from 1 hectare of arable land. The feed unit that was best provided with digestible protein was in crop rotations, in which, along with grain crops, perennial legumes and annual legume-grass grasses, as well as rapeseed and lupine, were cultivated. It was established that the greatest economic effect was achieved in eightfield crop rotations with a share of grains of 50 and 62.5%. An increase in the concentration of grain from 83.3 to 100% reduces the yield of grain, increases the growth of all production costs, which leads to a decrease in net income and a drop in the profitability of crop rotation as a whole.

The article presents the results of the research on a comparative evaluation of the efficiency of harrowing and applying herbicides when cultivating crops in graingrass rotation. It’s established that harrowing the crops under study without applying herbicides at the optimal time ensures the yield increase by 2.3-14.8 % depending on the way of tillage, and with the use of chemical wedding – by 3- 20.8 %. Buckwheat has the highest indicators, and winter rye – the lowest ones. The crops under study can be listed in the following descending order with regard to their suitability for ecologization of plant protection from weeds: winter rye, winter wheat, barley with clover, buckwheat and pea.

The paper deals with the need to develop combined tillage machines forming soil structure that is favorable for the growth and development of plants, sharply reducing wind and water soil erosion and allowing several actions in one single operation. The analysis of the existing methods of tillage is described, and the options for solving the problem are proposed: basic and surface tillage is provided by universal chisel machines, as well as universal combined disk machines. The advantages of the proposed designs are presented and experimental data are stated.

The paper presents the results of studies on the effect of pre-emergence application of the new herbicide Python, EC on weed infestation of crops and the yield of rape oil seeds. Biological efficiency in reducing the number of weeds in winter rape on the 30th day after application was 80.0-84.2%, spring rape – 79.3- 82.9%, which ensured the growth of oilseeds yield by 7.9-9, 2 dt/ha and 5.0-5.8 dt/ha respectively or by 23.5-27.4% and 26.6-30.9% in comparison with the control variant due to the reduced competition in cenosis and increase in the number of pods on the plant, seeds per pod and the 1000-grain weight.

The article presents the results of the research on the effect of the herbicide Pulsar Flex, WS (1.2-1.5 l/ha) on infestation and yield of pea grain. It’s established that in order to obtain the maximum effect this herbicide must be applied at the 1-3 leaves stage, which provides a biological efficiency of 80.8–89.5% and increases the grain yield by 13.7- 15.6%. When the herbicide Pulsar Flex, WS (1.2-1.5 l/ha) was applied at the 3-6 leaf stage, due to the phytotoxic effect on crops, no significant increase in the yield of pea grain was noted.

The paper presents the results of the research on the effect of herbicides on the yield of sugar beet and subsequent crops of crop rotation. It was established that with a double application of the herbicide Conviso One, OD (0.7 l/ha) + Mero, EC in sugar beet, the sugar yield increased by 14.1% compared with a triple application of Betanal Maxx Pro, OD (1.1+1.5+1.25 l/ha) in combination with Mitron, SC (1.5 l/ha) or Goltix, SC (1.0 l/ha). With a sufficient moisture during the growing season, no significant aftereffect of the herbicide Conviso One, OD (0.7 l/ha) + Mero, EC on the productivity of subsequent winter wheat, spring rape and green pea was identified. Under the influence of this factor the upward or downward variation of their yield was within 0.5-1.7% depending on the crop and method of tillage.

Using pesticide tank mixtures allows not only to expand the effect, but also to reduce the cost of treatment and the consumption rate of preparations. It was established that in the combined application of herbicides with UAN the variant Mais Ter Power, OD + UAN with a consumption rate of 1.5 l/ha + 30 l/ha had the highest biological efficiency, the death of weeds amounted to 93.1-99.4%. The most effective variant was Mais Ter Power, OD + UAN with a consumption rate of 1.0 l/ha + 30 l/ha, where the yield increase was 83.7 dt/ha. The number of grains per cob in that variant was 562.6 pieces, and the 1000-grain weight was 262.4 g. The maximum weight of the plant with the cob was 906.3 g and the weight of the cob in the husk was 340.2 g. The maximum application rate of Mais Ter Power, OD + UAN (1.5 l/ha + 30 l/ha) was phytotoxic for maize plants, they lagged behind in growth. The yield increase amounted to 46 dt/ha. The number of grains per cob in that variant was 491 pieces, and the 1000-grain weight was 221 g.

The research results of the economic evaluation of herbicide application on maize crops are presented in the article. It was established that the highest net income (391.4 $/ha) and profitability (39.3%) was obtained through the application of MaisTer Power, OD herbicide (1.3 l/ha) in the phase of the third leaf when growing maize on sod-podzolic sandy loam soil in the Central zone of Belarus. Use of such herbicides as Milagro Plus, OD (1.0 l/ha), MaisTer Power, OD (1.0 l/ha) + Francorn, SC (0.1 l/ha), Elumis, OD (1.5 l/ha) in the phase of 3 or 5 leaves of maize decreased the net income by 44.6-140.0 relative units per ha, and profitability by 3.0- 13.7% depending on the applied herbicide.

The results of comparative researches of two cycles in 2008-2011 and 2018- 2021 to study the impact of climatic changes on sowing terms of winter wheat are presented in the article. It was found that in the last ten years, the optimum sowing date of winter wheat in the central agro-climatic zone shifted by seven to ten days towards later terms due to the increase in the amount of active accumulated temperatures in the autumn period by 104-128oC depending on the studied sowing term.

Winter wheat yield formation has been studied depending on different sowing terms under the conditions of the Central part of Belarus. According to the results of the studies it has been established that among all the studied varieties, the highest yield was obtained when winter wheat was sown in the beginning of the third ten-day period of September and the first ten-day period of October and made up on average for the years of the researches 87.6 and 86.1 dt/ha, respectively. It was found that the density of productive plant stand is crucial for the formation of winter wheat yield. It, in its turn, depends on the biological and morphological characteristics of the variety, as well as the emerging weather conditions during the growing season.

The results of the researches on the optimization of sowing terms and application of nitrogen fertilizers in the cultivation of naked oat var. Korolyok on sod-podzolic sandy loam soil in the Central zone of Belarus are shown. It was discovered that in order to obtain the highest yield, naked oat should be sown in 7 days after the onset of physical ripeness of soil and nitrogen should be applied in a dose of N90 before presowing cultivation or in parts N60+30. In that case, the naked oat plants formed grains with the weight of 1000 grains of 26.4-27.2 g and high-grained panicle (57.7-58.4 seeds) which provided the grain yield of 47.7-50.9 dt/ha.

The results of the researches conducted in 2016-2019 on sod-podzolic sandyloam soils of RUE "Research and Practical Center of NAS of Belarus for Arable Farming" are presented in the article. The effect of sowing terms and fungicideaction seed dressers on the duration of preemergence period, field seed germination, yield and moisture of maize grain was studied. It was found out that early sowing term of maize (end of the 2nd ten-days period of April – beginning of the 3rd one) with treatment of seeds with Maxim XL preparation provided the most effective use of hydrothermal resources, which allowed saving 9.7-13.9 thousand/ha more plants and increasing the grain yield by 3.8-5.0 dt/ha in comparison with other variants of seed dressing. Sowing two weeks later led to a decrease in grain yield by 3.3 dt/ha and an increase in moisture content by 1.7%.

The article presents the data on maize productivity in terms of green mass, dry matter, feed units, metabolic energy and protein, obtained due to the experiments carried out on cohesive sandy soil in the central part of Belarus in 2019-2021. The structure of costs for growing and ensiling green mass of FAO 210, 230 and 250 maize hybrids with different plant density (70, 90, 110 and 130 thousand/ha), sowing dates (late April and early May) and harvesting dates (at the beginning and at the end of the dough stage) is shown. The cost price, net income and the level of profitability are calculated for different variants of growing the crop.

The paper presents the results of a three-year study on the effect of foliar application of nitrogen fertilizer (in the form of carbamide) to the spring triticale variety Novoye on the yield and protein content in grain in relation to growth and development stages. It was established that the highest grain yield in the experiment was obtained when N15 and N₂₀ were applied at the “flag-leaf” stage (BBCH 39) - 7.14 and 7.02 t/ha, respectively, which was 1.86 and 1.74 t/ha more than in the control variant. The highest protein content in grain was observed when N15 and N20 were added at the flag leaf stage (DK 39 - 13.8 and 13.9%, respectively, which was 7.8 and 8.6% more than in the control variant. The fertilizer background Р₆₀К₉₀ (in autumn), N₉₀ (pre-sowing cultivation) + N₃₀ tillering stage.

It is shown that Sudarynya variety provided higher energy efficiency of cultivation and harvesting technology of spring soft wheat than Rassvet, Laska, and Lybawa varieties. The energy efficiency coefficient increased by 14.7-18.2% when considering the energy in the grain, and the energy intensity of 1 ton of grain decreased by 10.4-15.7%. Application of nitrogen fertilizer at a dose of 100 kg/ha of active agent increased the energy content in the aboveground wheat mass by 34.4% and by 49.2% at a dose of 160 kg/ha of active agent. At the same time, the energy efficiency coefficient was equal to 7.9 and 7.0 units respectively; the energy intensity of 1 ton of grain was 4.9 and 5.5 GJ.

The article deals with the data on the efficiency of a split application of mineral nitrogen in a dose of N40 + N20 both separately and while treating vegetative crops of oil flax when 5-6 pairs of leafs unfold together with microelements in a chelate form NS=20-4, NK=10-12 and microfertilizers with modifying additives B, Zn in a sulphate form.
It’s established that a split application of mineral nitrogen in a dose of N40 + N20 increases the yield of flax seeds by 0.8 dt/ha or 5.2 % in comparison with N60 application during presowing cultivation. Combination of a split application of nitrogen and microfertilizers allows increasing the yield of oil flax seeds (on average over 2018-2020) by 0.4-1.4 dt/ha or 2.5-8.7 %.

The article deals with the results of studying the efficiency of the use of modern highly effective fungicides in winter wheat cultivation technology. Due to two year experiments their high efficiency against leaf and ear diseases was established. The studied systems of fungicide application allowed obtaining a high grain yield within 74.5-80.6 dt/ha that was suitable to be used for food.

It was established that the amount of precipitation in May determines the intensity of spring barley tillering (r=0.520). There was close correlation (r=0.862) between the level of barley lodging during the ripening period and the number of shoots per area unit at the phase of early booting, BBCH 30-31. At sufficiently high values (0.319 and 0.389) of the determination coefficient, the significant correlation between the amount of precipitation in May and June and the level of barley lodging was r=0.541 and r=0.624, respectively. The nine-point prediction scale of spring barley lodging resistance depending on shoot density at the stage of BBCH 30-31 was developed.

The influence of different doses of trinexapac-ethyl-based retardants on lodging resistance of spring barley and their effect on productivity elements and crop yield is shown in the paper. The application of trinexapac-ethyl at a rate of 75 ml/ha of active substance increases the resistance to lodging by 3.5-5.5 points; at a rate of 100 ml/ha – by 3.5-7.7 points, and at a rate of 150 ml/ha – by 7.5-9.0 points and save on average 4.8-7.4 dt of seeds per ha, and up to 8.2-10.7 dt of seeds per ha in the years when lodging was high.

The article shows the influence of the ways of the retardants application based on mepiquat chloride+ethephon on spring barley resistance to lodging, their impact on the elements of productivity and yield of the crop. A double treatment of barley at the ВВСН 31+ ВВСН 39 stages reduces the plant height by 6.5-19.1%, increases the resistance to lodging by 3.2 points and yield by 3.3-7.2 dt/ha. A single treatment of barley at the ВВСН 31 stage increases the crop resistance to lodging by 2.2 points and grain yield by 2.1-6.6 dt/ha.

The research results of studying of a rapeseed root canker pathogen (Phoma lingam Tode. Desm.) under laboratory conditions with the purpose of determination of optimum conditions of phomosis pathogen cultivation in order to receive the maximum spore bearing culture to make an inoculum for plants infection are described in the paper. The research revealed that the composition of the artificial growth medium had a greater influence on growth rate and colony diameter than lighting conditions. For P. lingam colony growth, V-4 and CGA were optimal media. For the spore formation process of the pathogen, the lighting regime was the determining factor. Sun lamps significantly enhanced the ability of the fungus to produce spores.

The results of studies on optimum nutrient media and cultivation conditions of lupine anthracnose pathogen (Colletotrichum lupini) are presented in the paper. The nature and growth rate of the pathogen, spore germination and sporulation rate were monitored. The optimum light regime for pathogen cultivation was determined. The aggressiveness of anthracnose pathogen strains on blue lupine variety Mirtan was determined by a laboratory method. The influence of infection process on growth characteristics of lupine seedlings during seed inoculation in spore suspension of pathogen was revealed.

The paper presents the results of the research conducted by the laboratory of field crops cultivation technology (Institute of Agriculture, Kabardino-Balkarian Scientific Center of the Russian Academy of Sciences) on the growth regulators effect on the productivity of new early ripening soya varieties (Irbis, SK Riana) that were bred by the Federal State Budgetary Scientific Institution "Federal Scientific Center "V.S. Pustovoit All-Russian Research Institute of Oil Crops" and the breeding company “Soya Complex” respectively. The preparations affected sowing qualities of seeds (increase of the energy of sprouting and germination rate by 113.9 and 124 % respectively). Significant yield increases were observed with Albit, LPS application in a dose of 50 ml/t of seeds before sowing and at the bud stage: 17.4 % (SK Riana variety) and 18.2 % (Irbis Variety) with the average yield not increasing 2.2-2.3 t/ha. Those variants of the experiment were characterized by the best indicators of economic efficiency.

The effect of the microbial preparation Polybakt, L, microfertilizer Ecogum, and the growth regulator on the yield and quality of flax fibre is shown. On average, over the years of studies the maximum yield of flax fibre (17.9-18.0 dt/ha) was obtained when the following fertilizers Ecogum Zinc-Complex, WS, Ecogum Bio, WS, Ecogum Zinc, Copper, Boron-Complex, WS together with Ecosil, WE 50 g/l were applied to growing plants at the “herring bone” stage. The application of Polybact, L in soil beginning from autumn provided 16.7 dt/ha of the fibre yield (1.2 dt/ha increase). When treating vegetating plants with Ecogum at the background of Polybact, L a minor yield increase was obtained (up to 17.4 dt/ha). The application of Polibact, L to soil increased the quality of flax fiber by 0.3 number with respect to the control. A combined application of the Ecogum fertilizer with the growth regulator at the "herring bone" stage increased the quality of flax fiber by 0.6-1.0 number.

The paper presents the results of the research on the impact of sowing dates and rates as well as methods of faba beans planting on the yield formation of green mass and grain under the conditions of the central part of Belarus. It’s established that on average for 2017–2021 the maximum yield of faba beans green mass (41,3-41,6 t/ha) was obtained at late sowing dates (in early/mid May), and grain (4,03–4,27 t/ha) – with early planting (mid/late April). The highest yield of green mass (38,9–39,7 t/ha) and grain (4,11–4,21 t/ha) of the crop is obtained with row planting (15 sm) and sowing rates of 0,4–0,5 mln/ha. Wide row planting (45 sm) provides the maximum yield of green mass (36,5–37,0 t/ha) and grain (3,92–4,08 t/ha) with sowing rate of 0,3 and 0,4 mln/ha.

The results of the researches for 2019-2020 on the effectiveness of the use of fiber flax seed fractions as sowing material are presented in the article. The sizes of fractions and their influence on sowing characteristics of seeds were established. In comparison to the original batch of seeds, a significant increase in the yield of flax products was provided by the cenosis formed by the sowing fraction with a volumetric weight of 712 g/l (65% of the original batch), with that profitability of flax cultivation was 64%. The seed fraction with a volumetric weight of 699 g/l (28% of the original batch) provided a positive trend towards increasing the yield of flax products and profitability of 56%. It was advisable to use the seed fraction with a volumetric weight of 686 g/l (6% of the original batch) for technical purposes, since the formed cenosis had a decrease in yield and product quality.

The impact of vegetation conditions on the formation of breeding and valuable traits in 9 domestic varieties of oilseed flax included in the State Register of Varieties of the Republic of Belarus was determined due to the field experiments in 2020-2021. It was established that climate factors influenced to a great extent on the duration of the vegetation period (80.3%) and the dates of phenological stages, the length of inflorescence (89.2%) and, to a lesser extent, on oil content (49.0%) and the 1000 seed weight (1.19%). A significant variability over the years of research was established for the following productivity traits: the number of pods per plant (V% to 27.5) and the number of seeds per plant (V% to 24.2). The conditions of the vegetation periods of 2020-2021 did not contribute to obtaining a high productivity of the studied varieties which on average amounted to 86.9 g/m2 and 96.6 g/m2 respectively in 2020 and 2021 and was 68.6 and 74.8% due to the number of seeds in pods. The varieties Alliance, Bonus and Slavyanin demonstrated the best results in respect of productivity, oil content and oil yield per area unit. They are the innovative developments of domestic breeding.

The research results of seed treatment efficiency when used together with ammonium molybdate are presented in the paper. It was found out that pre-sowing treatment of red clover seeds decreases the germinating capacity by 3.4-6.8% but increases the saving of plants up to 68.0-72.8%. The seed yield increase was 0.38- 0.66 dt/ha or 20.2-35.1%.

The results of the researches of pure-sown eastern galega (Galega orietalis L.), in two- and three-component agrophytocenoses cultivated without application of herbicides under the conditions of the central part of Belarus are presented in the article. The regularity of increase in productivity of two-component mixed crops of eastern galega compared to the pure-sown crop has been established.

In studies on soddy-podzolic sandy loamy soil of the experimental field of VNIIOU - a branch of the Federal State Budgetary Scientific Institution "Verkhnevolzhsky FANC" during 2009-2013. the possibility of using nitrogen from annual leguminous plants for feeding perennial grasses (meadow timothy grass) by using them as cover crops has been established. They, by increasing the content of assimilable forms of nitrogen and other nutrients in the soil, had a positive effect on the development of grasses in the autumn and spring periods, the formation of their biomass during the growing season, improving its quality, increasing the development of the root system of perennial grasses and the accumulation of nutrients in it. . The effective effect of cover crops was traced for 4 years, the total increase in hay crop during this time amounted to more than 120 c/ha, the economic effect was about 17 thousand rubles.

The article analyzes the results of studies on the formation of above-ground biomass yield by legume-grass swards based on Festulolium morphotype of meadow fescue (Festulolium braunii) in the 1st and 2nd years of use. It was established that the studied swards on average for 2 years of use formed 87.7 dt/ha of dry matter with meadow clover, 78.9-82.9 dt/ha with alfalfa, and 67.5-73.3 dt/ha with white clover. The share of legume components was identified amounting to 43-59% in the 1st year of use in swards with alfalfa, 42-46% - with white clover and 71.0% - with meadow clover, and in the 2nd year of swards use - 43-59% ; 42-46% and 71.0%, respectively.

Studies conducted on sandy loam soil in 2018-2021 showed that alfalfa var. Fraver and Mediana annually provided consistently high yields of green material (397-401 dt/ha on average for 4 years of life), dry matter (85.5-86.5 dt/ha), fodder units (71.8-72.8 dt/ha), exchange energy (80.5-81.5 GJ/ha) and crude protein (15.7-16.0 dt/ha). Plato, Timbale and Kamila alfalfa varieties formed high yield for 3 years out of four, Verco and Malvina 2 years, but on average it was not significantly inferior to the most productive variety, and only variegated alfalfa var. Vega 87 showed significantly lower productivity.

The article presents the results of the research on photosynthetic activity of plants in single species and binary plantings of awnless brome. It was established that when brome was used with clover of the second and third years of life in swards for hay, higher indicators of leaf surface area and photosynthetic capacity were formed with regard to single species plantings. In binary swards, the leaf surface area at the ear formation and budding stage of the legume amounted to 25.75-44.37 thousand m2/ha, in single component swards - 24.59-41.16 thousand m2/ha. The indicators of photosynthetic capacity of brome with clover plantings were at the level of 2761.64-2879.01 thousand m2×day/ha, in swards with brome - 2276.28-2521.92 thousand m2×day/ha. The net productivity of photosynthesis in single species plantings of brome was 3.33-3.55 g/m2/day, in binary ones - 3.26-4.02 g/m2/day.

The paper presents the results of the research on the productivity of multicomponent swards based on festulolium of reed fescue (Festulolium pabulare) morphotype, as well as the uniformity of distribution of aboveground mass over the cuttings during the growing season in relation to the years of use, taking into account prevailing weather and climatic conditions. It is shown that the yield of aboveground biomass of multi-component swards depends on the multi-species legume component included in the studied grass mixtures.

The paper presents the data on nutritional value of green fodder of sweet sorghum, sorghum-sudangrass hybrid and sudan grass grown on sod-podzolic sandyloam soils with the average content of potassium mobile forms, high content of phosphorus mobile forms, insufficient content of humus and a medium acid reaction of soil. The content of fibre in green mass at the heading stage, soluble carbohydrates, crude protein, metabolic energy and feed units is shown. The values of sugar-protein ratios and the content of digestible protein in a feed unit of sorghum crops are established. The variability of the indicators of green fodder nutritional value in terms of the years of research is identified. A correlation is established between the hydrothermal coefficient and the indicators of nutritional value of green mass of sorghum crops.

The results of calculation of metabolizable energy content in herbage of legumegrass swards for cattle feeding are given in the article. The calculations were done on the basis of protein nutrients, fat, fibre, nitrogen-free extractable substances, and the content of crude fibre using the following formulas: metabolizable energy (ME)=15.0-0.18хСF and ME=11.8-0.095хСF, where CF is the mass fraction of fibre in dry matter, %. It was shown that calculation of metabolizable energy using the formula of ME=11.8-0.095xCF gave almost the same results as the calculation based on crude protein nutrients, fat, fibre, and nitrogen-free extractable substances.

The results of the analysis of the influence of the temperature factor (average daily air temperature, sums of active and effective temperatures) during the springsummer period of winter rape vegetation on the duration of vegetation, yield, content of fat, protein and glucosinolate of 10 Belarusian varieties of this crop are presented. A strong negative relation (r=-0.74) between the average daily air temperature and the duration of spring-summer vegetation of winter rape is identified. A strong negative correlation (r=-0.86) is established between the sum of effective temperatures and the yield of winter rape oilseeds and between the content of fat and crude protein in oilseeds (r=-0.94), as well as an average correlation between the yield of oilseeds and the sum of active temperatures (r=-0.66) and the average daily air temperature (r=-0.56). A positive correlation of strong (r=0.72) and medium degree (r=0.52) is identified between the indicators of the sums of active and effective temperatures and the content of glucosinolates in seeds, as well as between the duration of springsummer vegetation of winter rapeseed and the content of glucosinolates r= 0.47.

The paper presents the results of the research and trials on the integrated crop production technologies used for potato cultivation together with the means of protection from diseases and growth stimulation. The efficiency of polyfunctional environmentally friendly protective and stimulating preparations Polyazophos and Polyslav is shown. Their application allows preventing diseases when treating potato tubers in autumn and spring as well as vegetative plants.

The established collections of genetic resources for food and agriculture have a great potential for new discoveries in genetics and advances in crop breeding. To improve the efficiency of using collections of plant genetic resources, it is necessary to characterize and evaluate accessions in respect of valuable traits. Providing breeders with germplasm and associative information regarding the identified traits helps a breeder to obtain a sample with the properties and qualities he needs. In this respect, the creation of trait-specific collections expands the possibilities for developing varieties with desired properties and is of great importance for accelerated creation of new varieties and hybrids of crops and, as a result, for ensuring the food security of countries.

The paper shows the results of the wheat (Triticum L.) collection study. The identified sources of economically important traits that can be used for spring wheat breeding are presented.

A histological and anatomical study of the stem of spring hard wheat samples differing in ecological and geographical origin and plant habitus was carried out. Interspecific and intervarietal features of the stem anatomical structure and their impact on productivity are identified. Efficient morpho-anatomical selection criteria were substantiated. In breeding for productivity, it is advisable to use forms with a developed chlorenchyma (0.6-1.0 mm2), an increased number of vascular bundles of parenchyma of the central cylinder (11–15) and vascular bundles of the primary cortex (13–17 pcs.) with large metaxylem vessels (r = 0.5–0.9). These parameters are available for evaluation at early stages of the breeding process, which ensures the improvement of breeding work due to reducing the time for creating new varieties and increasing the efficiency of breeding.

The paper states the results of the study of heterosis effect and character of inheritance of spring triticale hybrids F₁ traits obtained due to intraspecific and remote crossing. A comparative efficiency of different types of crossing with regard to the following traits is shown: a plant height, productive tillering, a spike length, a number of spikelets per main spike, grain weight per main spike and plant.

The paper demonstrates the main results and current directions of winter rye breeding in Belarus. The characterization of the varieties included in the National List over the last years is presented.

The results of comparative analysis of productivity elements of winter triticale var. Athlet 17, Blago 16, Dynamo, Uste, Belcanto, DD 608/14 and Trapero with and without flag leaf are presented in the paper. Leaf parameters were evaluated and its contribution to the formation of productivity elements was determined. On the basis of multiple correlation analysis, close conjugated correlations between flag leaf parameters and productivity elements were found.

The results of a comparative analysis of productivity elements and physical and chemical indices of winter triticale varieties and valuable variety samples combined into groups with maximum and minimum yield values are presented in the paper. The quantitative characters of the groups, their genotypic variability and correlation with the yield were evaluated. It was found that the group of high-yielding winter triticale samples was characterized by more expressed phenotypic homogeneity compared to the lower yielding group. Notable differences between them were evident in evaluating such characters as resistance to snow mould, overwinter survival, number of productive stems, and thousand seed weight.

The paper presents the results of studying the features of the inheritance of productivity elements and combining ability of winter wheat varieties under the conditions of the Republic of Belarus according to 3 traits: grain weight of the main ear, number of grains in the main ear and 1000-grain weight. Intervarietal F1 hybrids showed positive true heterosis: 39.5% - in terms of grain weight of the main ear, 22.7% - in terms of the number of grains in the main ear, 22.9% - in terms of the1000-grain weight. The inheritance of the yield structure elements occurred mainly in relation to the type of positive overdominance. The Amelia variety is of interest for breeding. It is characterized by a high GCA with regard to the yield structure traits.

On the basis of the researches on the collection material of winter soft wheat of different ecological and geographical origin, the sources of agronomic characters (productive bushiness, number of seeds in the main ear, seed weight in the main ear, ear length and thousand seed weight) were identified. Those sources were recommended as the initial material for winter soft wheat breeding.

The paper presents the results of the research on identifying the portion and degree of impact of agrometeorological factors on the variability of productivity of soft winter wheat cultivars. It’s established that its rate mainly depends on the genotype and agrometeorological conditions of the vegetation period. The hydrothermal regime during the period of tillering and ear formation predetermines to a great extent the amount of the future yield. The information on possibilities and frameworks of cultivars variability is necessary for breeding and agricultural production to solve the problems of obtaining maximum yields with a high profitability.

A species collection of oats with a different ploidy level was studied with regard to resistance to Pyrenophora chaetomiodes Speg. The accessions with juvenile resistance to Pyrenophora chaetomiodes Speg. and a low degree of damage at the flag leaf stage were identified to be included in breeding. A comparative study of oats species collection was carried out according to biometric indicators. When performing interspecific hybridization of oats in 33 crossing combinations 14 interspecific hybrids were obtained. They were colchicined and propagated applying the method of microclonal propagation.

The results of the researches of harmfulness of oat loose smut, determination of direct and latent losses of oat yield, influence of the pathogen on field germination, stem density, plant height, thousand seed weight, seed weight per panicle and biological yield are presented in the article. The viability of spore infectious material of loose smut under field and laboratory conditions was determined. Evaluation of the initial and breeding material for resistance to loose smut was conducted against the artificial infectious background in field and in phytotron in order to identify sources of resistance. Twenty nine oat varieties with high resistance (score 0) and ten varieties with practical resistance (score 1) were identified as sources of resistance among the oat species Avena sativa L, Avena byzantina Koch and Avéna strigósa.

The results of the study of new blue lupine variety Kupets in competitive and state variety trials are presented in the article. The main indices of productivity, seed quality, morphological characters and possible directions of use are described. On average for three years in the state variety trial system, the seed yield of blue lupine var. Kupets was by 2.6 dt/ha (10.6%) higher than the control. Seed protein content was 32-34%, alkaloids content made up 0.02-0.04%. In terms of dry matter yield, it exceeded Mirtan control variety by 12.3 dt/ha (18.5%).

The research results of phenotypic manifestation of branching reduction gene "sbr" in hybrid and breeding material of yellow lupine (Lupinus luteus L.) are presented in the article. It is established that the character of "reduced sympodial branching" in yellow lupine is a monogenic recessive character and controlled by "sbr" gene. Four appreciable samples with reduced sympodial branching (C-BC-JC- 11, C-BC-LC, BGB 11 x BGB 1 (large-seeded), Eifel) which were close to those of spike-like type by their parameters and are of interest for breeding on the territory of the Republic of Belarus have been isolated.

The parameters of a spike-type yellow lupine variety model which is based on the main characteristics of traits and properties of highly heterosis hybrid of this crop are highlighted in the paper. It is pointed out that the available gene pool allows for the development of intensive spike-type yellow lupine varieties with potential yield of total dry biomass of 14-16 t/ha and seeds of 6-7 t/ha in the near future. Varieties of this model are suitable for cultivation both for grain and for green mass on all types of soils.

The paper presents the results of the study of common millet accessions of the Belarusian origin from the All-Russian Institute of Plant Genetic Resources (VIR) collection for further use in breeding under the conditions of the Republic of Belarus. As a result of the conducted research the following sources of economically valuable traits are identified: early ripeness – 4 pcs., short stalks and resistance to lodging – 1 pce, productive tilling capacity – 13 pcs., high grain yield – 16 pcs., green mass and dry matter – 11 pcs., grain, green mass and dry matter – 9 pcs.

The article presents the results of studying buckwheat cold resistance at the juvenile stage of development. It’s established that the best way to sterilize buckwheat seeds is a 10-15 minute treatment in 94% sulphuric acid. The optimum temperature for cold resistance selection is +5 ºС. The studied buckwheat varieties differed significantly in terms of the degree of cold resistance, at the same time even low coldresistant samples had single resistant genotypes. The maximum number of germinated plants and a greater percentage of seedlings with a germinal root length of 1 cm or more were observed on the ½ MS medium without additives (control) and light and ½ MS +2 mg/l IBA without light.

The paper demonstrates the results of the study of the efficiency of the method for selecting genotypes with regard to the interaction of some contingent traits that characterize plant habit and population productivity. Five competitive buckwheat cultivars are developed: 3 diploid cultivars and 2 tetraploid ones. The conclusion made is that it is worth to use this method for further cycles of selection to improve buckwheat populations in breeding.

The paper indicates the results of the research on harmfulness and prevalence of the agent Sporisorium destruens (Schltdl.) Vánky in common millet. The analysis of aggressiveness and virulence was conducted; the varieties resistant to the pathogen were identified on an artificial infectious background.

The paper presents the results of the research on creating and evaluating samples and hybrids of spring rape obtained by the remote hybridization method. The selection of parents with regard to the traits that are valuable for breeding is carried out; interspecific hybrids F1 of spring rape are created with the use of in vitro culture; seed material with new utilitarian traits is obtained and evaluated in terms of a set of economically valuable traits including quality indicators of oil seeds. A strong correlation is identified between the yield and the number of pods per plant, the number of pods per plant and the number of seeds per pod (r=0.82 and 0.72). Due to the conducted research the spring rape variety Izumrud has been submitted for testing to the State Inspection for Testing and Protection of Plant Varieties. The variety has a high productive capacity and a shorter vegetation period. It is characterized by resistance to diseases, lodging and grain fall, even maturity and responsiveness to intensification means.

The article presents the results of the analysis of fatty acid composition of varieties and samples of rape, which are characterized by a high content of unsaturated oleic acid: 58.1-67.8% - in winter rape and 54.8-67.5% - in spring rape. The best samples with oleic acid content of 74-76% and linoleic acid of 10-15% and linolenic acid of 3.5-4% are similar to olive oil in terms of fatty acid composition. A positive correlation (r=0.93) between oleic acid content and rape oil content is identified. A strong positive correlation between the content of oleic and linolenic acid (r=0.99), as well as arachidonic acid (r=0.99) is shown. A strong negative correlation is established between the level of linoleic acid and arachidonic acid (r=-0.90), as well as with eicosenoic (r=-0.85) fatty acids. It is shown that anti-nutritional erucic acid is in a strong positive correlation with arachidonic (r=0.99) and stearic (r=0.73) acids. A strong negative relation is established between erucic acid and oleic acide (r=-0.89), and a medium relation - with linolenic (r=-0.57) acid.

The article presents the results of breeding work on the creation of initial material of corn applying chemical mutagenesis method. As a result, a new initial material with high cold tolerance indicators was created that was suitable for developing highly productive corn hybrids with a high adaptive capacity.

The evaluation of F₁ and F₂ hybrid material of fibre flax for resistance to Septoria linicola ((Speg.) Gar.). is given based on the complex of agronomic characters. Valuable genotypes have been identified for further targeted breeding.

An assessment of 10 varieties of oilseed flax of Belarusian breeding was carried out in terms of linear sizes, morphological and physical characters, and organoleptic properties. All samples have linear sizes typical for seeds of the crop, such as: length 0.42-0.49 mm, width 0.21-0.23 mm, thickness 0.08-0.12 mm. High values of seed volume, its elongation and thickening were noted in such varieties as Bonus and Ilim (seed volume - 0.053 cm2, seed elongation - 2.20 and 2.16, respectively, thickening - 0.51). All studied varieties had crumbly, moist and oily structure, uniform appearance with the inclusion of shell particles. Plant height varied within 46.9-60.1 cm2, technical length 30.7-46.9 cm2, number of bolls 8.6-15.3, number of seeds in a boll 59.1-106.3, seed weight 0.346-0.600 g, thousand seed weight 4.88-6.67 g, productivity 79.1-117.9 g. The results obtained indicate that varietal characteristics affect the values of indices characterizing morphological and physical characters, organoleptic properties and linear sizes of seeds, and they must be taken into account when using varieties as raw materials for food industry.

The results of long-term targeted breeding work to develop initial material for oilseed flax breeding using inter-variety hybridization and sampling from hybrid populations and the results of their study in breeding and state variety testing are presented in the paper. According to the complex of characters, the following lines of oilseed flax have been isolated: mid ripening line 52-5-9-2 (Slavyanin) and early ripening 07-16-4-2 (Bonus). The varieties are characterized by high yield potential (Slavyanin variety – up to 3.08 t/ha, Bonus variety – up to 2.86 t/ha), oil content (up to 43.45%), high resistance to fusarium wilt (up to 13% against the infectious and provocative background). The plants are aligned in height, bloom and ripen together. In 2022, the varieties were registered in the State Variety Register and were recommended for cultivation in all regions of the Republic of Belarus.

The results of comparative adaptability evaluation of 42 samples of fibre flax collection of various ecological and geographical origins on the basis of «total fibre yield» character are presented in the paper. The following highly productive samples were identified: Tonus, Nord, Diplomat, Gorizont and Dobrynya (Russia), Esman (Ukraine), B-168 and B-192 (Lithuania), Alej (Belarus). They were most adaptive to the soil and climatic conditions of the northeast part of Belarus and should be used as effective sources in breeding for high yields of total fibre and adaptability.

The results of the application of the breeding value index (calculated on the basis of the scalar ranking method) in fibre flax breeding in the evaluation of 368 F2 hybrid plants obtained as a result of tester and diallel crossing schemes are presented in the article. It has been established that the best indices of breeding value belong to hybrid plants that were obtained as a result of crossing of parent pairs: Aley x Smena (0.726), Smena x Persej (0.722), Persej x Aley (0.696) and Snezhinka x Yarok (0.650).

A comparative analysis of 10 varieties of oil flax of Belarusian breeding and 9 varieties of fiber flax of different maturity groups was carried out in terms of the development of the embryonic root system under laboratory conditions by the method of seed germination in rolls. It was established that at the initial stages of growth oil flax varieties formed a larger length of the germinal root and its weight, as well as the total length and weight of roots. The average value of the indicators for oil flax was 18.02-21.16 cm; 0.061-0.070 gm; 798.7-1016.8 cm; 2.529-3.437 gm, respectively, for fiber flax varieties - 15.49-18.66 cm; 0.047-0.060 gm; 604.43-896.18 cm; 1.819-2.953 gm respectively. The varieties of oil flax (Ilim, Focus, Bonus) and fiber flax (Taler, Mogilevsky, Orshansky-2) with high indicators of the studied traits for the development of the embryonic root system were identified. They are suitable for the use in breeding when creating crop varieties that are resistant to stressful conditions.

The results of a comparative evaluation of late ripening meadow clover varieties in a collection nursery are presented. The duration of the development stages and growing season depends to a great extent on meteorological conditions of the year. The flowering stage, depending on meteorological conditions, shifted upwards or downwards by ± 10 days. The duration of the growing season varied within 125-145 days from year to year and amounted to 135 days on average over three years. The sources for further breeding work were identified: for high yield of green mass Atlant - 8.1 kg/m², Pozdny-A - 8.3 kg/m² and Vityaz - 8.6 kg/m²; dry matter - Mut 6-4-48 - 2.0 kg/m², Atlant - 2.0 kg/m², Pozdny-A - 2.1 kg/m²; high foliage - Dymkovsky - 40.4%, Pozdny-A - 41.5%, Atlant - 42.4%, Mut 6-4-48 - 43.4%; dry matter content in green mass - Dymkovsky - 23.7%, Pozdny-A - 24.1%, Mut 6-4-48 - 25.0%; seed yield - Vik-7 - 23.6 g/m², SGP-6 - 24.5 g/m², Sozh - 25.3 g/m² and Mut 19-1-1 - 25.7 g/m².