The article deals with the results of the research on productivity of specialized cereal crop rotations with a different degree of concentration of cereals. The comparative evaluation of the crops referring to different economic and biological groups is carried out in terms of grain yield, fodder units and digestible protein per ha and planting.

The paper presents the research results on the impact of the herbicide Corsair Super, WSC (1.2-1.6 l/ha) on weed infestation of plantings and grain yield of peas. It’s established, that biological efficiency of the preparation is 77.2 – 81.4% in terms of the number of weeds and 86.6 – 89.8% with respect to their weight. With the use of the standard herbicide Basagran, WS (3.0 l/ha) the indicators are 77.6 and 82.8%, respectively. The application of the herbicide Corsair Super, WSC (1.2-1.6 l/ha) provides 17.0 and 19.9% of the grain yield increase of peas in comparison with the control, and the herbicide Basagran, WS (3.0 l/ha) – 13.3 %.

The article presents the results of the research on herbicides application to winter wheat plants. It’s established that under the existing conditions the herbicides Alister Grande, OD (0.75L/ha) and Complete Forte, SC (0.5 L/ha) ensure the greatest destruction of weeds when applied at the autumn tillering stage of the crop. In this case the number of weeds reduces by 99.4 % and 98.5 % respectively and their wet weight – by 99.9 % and 99.8 %. This provides the greatest increase of winter wheat yield (39.2 %). The application of the studied herbicides before winter wheat sprouting promotes the yield increase by 22.2-26.7 %, at the 2-leaf stage – by 31.1-34.4 %, and at the spring tillering stage – by 27.3-30.1 %.

The article presents the results of the research on the effect of the Corum herbicide, WSC (1.0-1.5 l/ha) + SAS Dash (1.0 l/ha) on weed infestation of plantings and seed yield of field beans. It’s established that biological efficiency of the preparation is 78.5 – 85.5% with respect to the number of weeds and 82.0 – 87.4% with respect to their weight. With the use of the standard herbicide Pulsar, WS (1.0 l/ha) the indicators are 87.3 and 86.6% respectively. The application of the Corum herbicide, WSC (1.0-1.5 l/ha) + SAS Dash (1.0 l/ha) provides, on average, 29.5 and 33.9 % of the seed yield increase of field beans in comparison with the control during the research period.

The paper states the research results on the effect of potassium fertilizer on the productivity and quality of fibre flax cultivated on sod-podzolic fixed sandy loam soil, containing 145-180 mg/kg of mobile potassium in the arable layer. The optimal dose of potassium fertilizer was 120 kg/ha of active ingredient, which provided 7.2. dt/ha of seed yield, 46.6 dt/ha of flax retted stalks, 14.4 dt/ha of fiber, including 8.6 dt/ha of long one and 43% of flax cultivation profitability. In the total flax yield removal the share of potassium fertilizer was 8-11%, potassium consumption from soil was 89-92%. The application of potassium fertilizer did not practically affect potassium consumption for the formation of one ton of fiber, which amounted to 44.2-45.8 kg of K₂O.

Grain unit is one of the main indicators of technological milling qualities of grain. The grain of spring wheat of the Lubava variety with a high natural weight was obtained with the application of N₁₅ and N20 at the BBCH 71 stage, 807 g/L and 802 g/L respectively or 8.6 % and 7.9 % higher than the control. The highest protein content in grain was observed with the application of N₁₅ and N₂₀ at the grain ripening stage (BBCH 71) – 14.4% and 14.9 % respectively, which was 3.6 %-7.9 % higher than the control (the background Р₆₀К₉₀ (in autumn), N₉₀ (presowing cultivation) + N₃₀ (tillering stage).

The article presents the results of applying new forms of liquid complex fertilizers (chlorinecontaining and chlorine-free) with chelated forms of microelements B, Zn, Cu and with biologically active additives (growth regulators Ekosil, Ecogum, Epin). It’s established that their application provides the yield increase of oil flax seeds on average by 1.1-3.5 dt/ha or 7.2-22.9 % compared to the background and by 4-7.5 dt/ha or 35.4-66.4 % compared to the control (without fertilizers) on sod-podzolic light loamy soil.

The paper presents the research results on the effect of microfertilizers on the yield of the oats variety Mirt with a different level of nitrogen nutrition. It was established that the application of the microfertilizer Ultramag Combi, WS (2.0 l/ha) at the stem elongation stage (AC 31-32) against the background N₉₀ and N₆₀₊₃₀ provided the highest oats yield (54.3 and 54.2 dt/ha). Due to the application of the preparation the yield increase amounted to 3.6-3.7 dt/ha (7.1-7.3 %), which was approximately equivalent to the additional application of nitrogen N₃₀ at the time of pre-sowing cultivation or at the tillering stage in comparison with pre-sowing use of N60.

The paper deals with the results of the research on the impact of soil cultivation on the maize grain yield under the conditions of the Central zone of Belarus. Minimizing and failure to meet the time for soil cultivation reduced that indicator only by 0.3-4.3 %. The least difference in the maize grain yield in comparison with annual soil ploughing was observed with combined cultivation involving alternation of ploughing and chiseling in crop rotation. Subsoil ploughing to a depth of 45 sm increased the maize grain yield by 2.5 % with annual tillage and by 1.9 % - with annual chiseling.

The article presents the results of the research on the relation of weed infestation of crops and the yield of winter rye grain to the methods of tillage, dates of harrowing and herbicide application. It was established that on highly cultivated sod-podzolic sandy loam soil with a low natural weed infestation of crops, plowing and chiseling didn’t differ significantly with respect to the effect on the grain yield of that crop. The differences in the yield of winter rye between the optimal period of harrowing and chemical weeding in that case amounted to only 0.9-1.1 % and were inaccurate.

The paper demonstrates the results of the research on the impact of basic soil cultivation methods and nitrogen fertilizers application on the yield of oats variety Mirt. It was established that when ploughing was changed into chiselling and disk harrowing weed infestation of oats was respectively 1.2 and 1.4 times higher before chemical weeding. After application of the herbicide Prima (0,6 L/ha) weed destruction didn’t practically depend on the studied methods of basic soil cultivation. The highest grain yield was obtained when oats was cultivated after ploughing and amounted to, on average, 46.6 dt/ha regarding the studied doses of nitrogen. When ploughing was changed into chiseling that indicator reduced by 2.4 %, and into disk harrowing – by 7.9 %. Nitrogen application in a dose of N₉₀ (47.3 dt/ha) and N₆₀₊₃₀ (48.2 dt/ha) after ploughing provided the highest grain yield of oats.

The article demonstrates the results of the study of winter wheat yield formation in relation to different sowing dates under the conditions of the central zone of Belarus. In accordance with the findings it’s established that the highest winter wheat grain yield regarding all the studied varieties is obtained with sowing at the beginning of the third ten day period and amounted to 88,5 dt/ha, on average for the research years. It’s established that winter wheat yield is mainly formed due productive crop stand, which in its turn depends on biological and morphological peculiarities of a variety as well as on weather conditions during the whole vegetation period.

The article presents the results of the two-year research on the productivity and accumulation of dry matter in plants and cobs that are different in early ripeness of maize hybrids (FAO 200, 230 and 260) in relation to crop density (70, 90, 110, 130 thousand plants/ha) and sowing dates (with gooseberry bud break and in 2 weeks). It’s established that the highest yield of green mass regardless of sowing dates is formed with the maximum density of plants, while the highest yield of dry matter (20.0 t/ha) is provided by the hybrid FAO 260 (DN Galateya) sown early with a crop density of 110 thousand plants/ha. The hybrid FAO 230 (Polessky 202) shows the equal yield (17.6–17.7 t/ha) with the same crop density irrespective of the date of sowing, and the most early ripening hybrid FAO 200 (DN Pivikha) has the highest yield (18.5 t/ha) during the second sowing period and plant density of 130 thousand plants/ ha. A more favorable temperature in the first half of the growing season during the second sowing period contributes to reducing the period "sprouts-blooming” by 9-10 days, which positively affects a further course of maize plants development and in this connection provides a greater accumulation of dry matter during the dough stage before harvesting.

The article deals with the research results on the relation of the grain yield to the plant height of 15 varieties and variety samples of spring soft wheat bred in the Research and Practical Center of the NAS for Arable Farming. It’s shown that without lodging the correlation between the yield and plant height is linear and direct. At the same time the degree of contingency is greater at the beginning of stem elongation and at the flag leaf stage than at the stage of full ripeness.

Different methods of fixing plant material of spring barley were studied while conducting analyses to determine the content of 3-indoleacetic acid (warm ethanol, drying, freezing). It was established that the methods of fixation affected greatly the number of 3-indoleacetic acid to be determined. Wave detection length was defined more precisely while identifying heteroauxin and gibberelic acid CA₃ with the use of HPLC (high performance liquid chromatography) for spectrophotometric detector.

The paper presents the results of the hormone level assessment in plants of spring barley of three varieties – Magutny, Reider and Adaman. The effect of growth regulators Messidor, Moddus and Seron on the content of 3-indoleacetic and gibberelic acids in barley plants during stem elongation is established.

The paper presents the results of the research on relation of crude protein content in winter wheat grain to the conditions of cultivation. It was established that the studied factors changed the above mentioned indicator by 0.1-5.1 % or 0.7-60.7 % in relative terms on sod-podzolic sandy loam soil in the Central zone of Belarus. Nitrogen application in spring, weather conditions during the spring and summer period and herbicides application had the greatest effect on crude protein content in winter wheat grain. Under the influence of those factors the yield of crude protein per hectare increased by 1.1-2.8 times in relation to winter wheat cultivation technology.

Due to the research it’s established that treatment of winter rape with nitrogen-fixing and phosphate-mobilizing preparations during the period of an active plant growth and a great need for fertilizer elements is an effective technique for increasing the crop yield without increasing a load on the environment. Foliar application of the preparations Agromik, Bactopin and Gordebac in a dose of 4 l/ha at the booting stage (BBCH 30-33) contributed to the increase of oil seeds yield by 6.1-7.3 dt/ha or 14.1-16.9 % in relation to the control. When treating the crops at the heading stage (BBCH 52-56) the maximum yield increase was obtained due to the application of Gordebac (5.3 dt/ha or 12 %) and Bactopin (4.3 dt/ha or 9.7 %). With a double application of the preparations (BBCH 30-33+ BBCH 52-56) the yield increased by 4.9-8 dt/ha or 11.2-18.3% in relation to the control.

The paper presents the results of the research on the effect of chemical mutagenes of nitrosomethylurea and nitrosoguanadine with different concentration and exposition on filed germination, survival, phenotypic variation of the fibre flax varieties Mogiliovsky, Ritm, Malakhit, Drakkar. As a result of the conducted research it was established that chemical mutagenes in the nursery of mutants of the first generation М1 reduced field germination of fibre flax seeds, survival, slowed down plant development increasing the duration of the vegetation period. At the same time increasing the concentration of mutagene strengthened a negative impact on seeds and plant development. The studied concentrations of mutagenes reduced field germination of all the studied varieties of fibre flax by 18.2-62.4 % in comparison with the control. A negative impact of chemical mutagenes on survival of fibre flax plants in direct proportion to their concentration and exposition was observed.

The paper deals with the results of the research on Eastern galega (Galega orientalis Lam.) in its pure form as well as in mixed agrophytocenoses in the central part of the Republic of Belarus. The performance of the basic legume component in mixtures cultivated without herbicides is evaluated. The botanical composition of grass mixtures is identified. The regularity for increasing the yield of mixed is established.

The paper presents the results of the research on cultivating Hungarian sainfoin (Onobryhis arenaria D.C.) in pure and mixed agrophytocenoses for obtaining high quality hay under the conditions of the central part of the Republic of Belarus. The regularity for increasing the yield of three component mixtures with Hungarian sainfoin in comparison with its one species planting is established. On the basis of the findings the method of selecting components and composition of legume and legume-grass mixtures with sainfoin has been developed for obtaining high quality hay.

The paper analyzes the results on the impact of sowing rates and dates, doses of nitrogen fertilizers on field germination, preservation and yield of meadow clover and a cover crop. It’s established that proper seedlings are formed during the spring sowing period. Field germination varies from 40 % to 58 %, and during the summer sowing period it varies from 26.5 % to 32 %. With the increase of meadow clover sowing rates from 2 to 6 mln seeds/ha its yield increases by 11.2 %. The increase of the dose of nitrogen fertilizers applied to a cover crop from N₆₀ to N₁₂₀ during the first year brings about the reduction of the yield of meadow clover by 8.8-9.3 %. A later barley harvest for grain reduces the productivity of meadow clover by 8-8.3 % in comparison with the variants after harvesting at the grain milk stage.

The article states the results of the research on identifying the most optimal sowing dates, doses of nitrogen fertilizers application to a cover crop, sowing rates of clover and barley. It’s established that with cultivating clover for green mass the highest net income (2280.1-2263.4 ruble/ha) and level of profitability (130.9-123.8%) is provided when it is sown without a cover crop in April at a rate of 4 and 6 mln ps/ha. When seeding clover with a cover crop the highest net income (2162.7-2262.7 ruble/ha) and profitability (102.5%) is provided with clover sowing rate of 4 and 6 mln ps/h and barley harvest at the stage of milk-wax ripeness at a sowing rate of 4 and 6 mln ps/ha against the background of N₆₀ application.

The article presents the results of the research conducted due to a long term stationary experiment on studying the cultivation mode of legume grasses on the basis of meadow clover in different types of specialized crop rotations. The effect of concentration, duration of use and period of clover return to the same place in crop rotation on the replenishment of the organic matter content and basic components of mineral nutrition in soil is established.

The productivity of alfalfa was studied on cohesive sandy soil in 2019-2020 with the application of different techniques of sowing and protection from weeds. It was established that sowing alfalfa after harvesting winter rye for green mass with further disking, harrowing and rolling allowed managing without herbicides and obtaining 215.5 dt/ha of dry matter for 2 years totally. At the same time when sowing alfalfa in spring after autumn plowing and applying the herbicide Rodimich, 1 l/ha or the tank mixture (Rodimich, 0.75 l/ha + Bazagran, 1.5 l/ha), the yield was 149.1-150.6 dt/ha, and without a herbicide protection it was even less - 130 dt/ha. Even planting alfalfa to winter rye to be harvested for green mass, as well as direct sowing after harvesting rye for green mass without the application of herbicides showed a higher total yield of dry matter, amounting to 172.8–192.8 dt/ha.

The article analyzes the results of the research on comparative productivity of perennial grasses cultivated in pure forms and grass mixtures for 2016-2020. It’s established that alfalfa in its pure form provided the highest total yield (386.2 dt/ha against the background N₀, 409.9 dt/ha against the background N₉₀) as well as binary mixtures with alfalfa (337.2 dt/ha against the background N₀, 421.6 dt/ha against the background N₉₀). Also binary grass mixtures of alfalfa with festulolium and broom provided the highest total output of crude protein amounting to 57.8-74.9 dt/ha against the background N₀ and 75.7-88.1 dt/ha against the background N₉₀. The assessment of the uniformity of yield distribution was carried out with the use of the uniformity index. It was established that alfalfa in its pure form had the highest uniformity index (0.63-0.65) and grass mixtures with alfalfa – 0.64-0.77, which witnessed a higher drought resistance of the crop in relation to clover.

The paper states the results of the route research on prevalence of pathogens on common millet in the Republic of Belarus. It’s identified that the following leaf blights are prevalent on common millet: two pathogens of Helminthosporium blight - Bipolaris panici-miliacei Y. Nisik and Bipolaris sorokiniana (Sacc.) Shoemaker, as well as Piricularia disease – Pyricularia grisea Cooke ex Sacc. Biological peculiarities of micellium growth of the identified pathogens on artificial media are examined. For obtaining high quality inoculum pure culture of Bipolaris panici-miliacei should be incubated on potato dextrose agar and pure culture of Pyricularia grisea – on millet agar.

The characterization of nutritional and feed value of cup plant (Silphium Perfoliatum) relating to the development stages and a type of economic application is presented. It’s established that at the booting stage, when cup plant (Silphium Perfoliatum) is used for cattle feeding in the green conveyor system the metabolizable energy content in cup plant biomass varies from 9.8 to 10.4 megajoule, the digestible protein content amounts to 66.8-91.2 g per kilo of air-dry matter, and the digestible protein content per fodder unit reaches up to 76.8 g and 118.5 g, which is in line with the dietary standard of production animals. At the anthesis stage, when cup plant (Silphium Perfoliatum) is harvested for silage the nutrient content amounts to 9.7 and 10.1 megajoule, 84.2 g and 90.4 g, 109.4 g and 120.5 g respectively. The maximum nutritional value of cup plant (Silphium Perfoliatum) is established at the heading stage beginning before the completion of the booting stage and flowering of the third tier of inflorescence. During the stages the crude protein content in green mass reaches up to 148-153 g, the digestible protein – 101-105.4 g, and the digestible protein content per fodder unit amounts to 123.2-131.8 g.

Economic and agronomic efficiency of the application of mineral fertilizers and straw in the second planting of maize was studied on cohesive sandy-loam soil with the increased content of phosphorus and potassium in 2018-2020. It is established that when 60 t/ha of cattle stable manure is applied during the first year, a high yield and the lowest cost of 1 t of grain or feed units is provided by the variant of harvesting maize for grain, followed by a straw plowdown and applying 30 kg/ha of nitrogen, and 45 kg/ha of potassium during pre-sowing cultivation during the following year, and applying 60 kg/ha of nitrogen in the form of urea at the 6-7 leaves stage. Against the background without maize straw, when the crop is harvested for silage, this variant is also the best, but the net income in this case is lower by 70.5-89.9 rubles/ha.

The paper presents the transfer factors (TF) of ¹³⁷Cs to green mass of sugar sorghum, sorghum-Sudan hybrid, Sudan grass cultivated on sod-podzolic sandy loam soil with the application of different fertilizer systems. It’s established that the application of phosphorus-potassium fertilizers contributes to the decrease of TF of ¹³⁷Cs to green mass of sugar sorghum by 21-26%, sorghumSudan hybrid by 17-22%, Sudan grass by 10-16%. When applying mineral fertilizers to sugar sorghum and sorghum-Sudan hybrid, the lowest TF of ¹³⁷Cs to green mass is observed with the following fertilizer system: N₇₀Р₆₀К₁₀₀and N₉₀Р₆₀К₁₀₀, Sudan grass – in the variants N₇₀Р₄₀К₁₀₀ and N₉₀Р₆₀К₁₀₀.

The paper deals with the state of breeding of winter rye hybrids F₁ in Belarus and peculiarities of their introduction. The ways of obtaining seeds F₁ of linear and population hybrids are presented, the risks and yield losses related to growing winter rye hybrids F₂ are shown.

The article presents the main results of studying the collection of CMS-forms, self-fertile lines and population varieties of winter rye in the course of creating high-yielding F₁ hybrids. The best 30 genotypes with a high degree of GCA are identified. Their morphological and economically valuable traits are established. Paired crosses of 10 MS-testers, 30 isolated inbred lines and 4 population varieties are carried out. 340 hybrid combinations are obtained. 8 interlinear and 12 linearpopulation combinations with a set of economically important traits are identified. Their parent components will be suitable for the creation of new high-yielding F₁ hybrids.

The addressing food security issues in the face of climate change and predicted adverse impacts on the efficiency of agricultural systems is closely linked to the availability of a wide range of crops and varieties that meet the requirements of modern production and are adapted to changing soil and climatic conditions. Crop genetic resources are a resource basis for the development of new varieties and hybrids; to conserve them the base and active collections of Cucurbitaceous crops were created to ensure their long-term and medium-term conservation and targeted use in breeding. In the course of the conducted work to replenish and optimize the seed collection of Cucurbitaceous crops 389 samples of modern breeding and local traditional varieties, as well as breeding material, were stored for long-term and medium-term conservation. As a result of the study of collection accessions and their use new promising varieties of cucumber, watermelon, melon, pumpkin, vegetable marrow and summer squash were created.

The article presents the results of studying collection accessions of winter rye in order to identify the sources of economically important traits (winter hardiness, yield, 1000 grain weight, amount and weight of a grain per spike, plant height, productive tilling capacity) for further targeted use in the breeding process in Belarus. Collection cultivars were identified and proposed as potential sources of economically important traits of winter rye: with a high yield (up to 1128.8 g/m²), short stems (from 107.5 cm to 137.5 cm), with a large weight of 1000 grains (more than 40 g), with a high productive tilling capacity (up to 8.9 stems per plant).

The paper presents the results of a comparative analysis of productivity components of winter triticale varieties cultivated in line with traditional and intensive technologies in the central region of Belarus in 2019-2020. The degree of variety response to strengthening the technology intensification as well as its impact on the amount and variability of quantitative traits was evaluated. The influence of quantitative traits of winter triticale on the formation of yield and harvest index was established.

The article shows the evaluation results of suitability of Mexican index (Mx), Canadian index (Ki), spike linear density index (SLDI) and crop productivity index (CPI) for selection of highly productive genotypes based on correlation analysis of the yield of 16 Belarusian varieties of winter triticale with selection indices. It’s established that CPI and Ki are suitable for selection of winter triticale breeding material with respect to productivity at early stages of breeding as regardless of meteorological conditions they have accurate positive strong and medium correlations with grain yield: (r=0.93**; r=0.89**; r=0.87**; r=0.85** и r=0.91**) and (r=0.88**; r=0.54*; r=0.82**; r=0.83** и r=0.89**) respectively.

As a result of a comprehensive study of 165 spring triticale collection accessions of different ecological and geographical origin the sources of a high yield, short stalks, early ripeness, 1000 grain weight as well as the sources of a high content of crude protein, crude gluten, starch have been identified for targeted use in breeding under the conditions of the Republic of Belarus.

The article presents the results of the study of the parameters of the primary and secondary root system development in short- and long-stemmed samples of winter wheat for the creation of high yield varieties suitable for soils with different fertility levels. The best genotypes are identified in terms of growth rates of embryonic and secondary roots and the total weight of the root system. It’s established that in medium- and long-stemmed samples the length and weight of roots is 10-20% higher than in short-stemmed ones. It’s identified that the genotype plays a crucial role in forming the parameters of the primary and secondary root system, which witnesses the need to include these traits in breeding programs for the development and selection of varieties that are more productive and adaptable to different soil conditions.

The paper presents the results of the laboratory evaluation of drought resistance of winter wheat variety samples in respect of their ability to germinate on osmotically strong sucrose solutions as well as comparison of the obtained data with their field productivity. According to the findings valuable breeding samples with a higher productivity in dry conditions were identified. In the course of conducting analysis on a highly concentrated sucrose solution under laboratory conditions a high correlation between the yield and level of drought resistance was established, which says about advisability to apply the method in breeding.

As a result of a comprehensive study of 90 varieties and collection accessions of winter soft wheat of different ecological and geographical origin the sources of short stems and resistance to lodging, which can be used in breeding, have been identified.

The efficiency of selecting resistant genotypes with the use of selective media is studied. Varietal specificity relating to this trait is identified and resistant genotypes are identified. It’s established that the methodology for selecting resistant varieties in selective media should combine the breeding material assessment and selection of resistant genotypes in terms of biometric indicators with their further check on resistance under ex vitro conditions and phytoexamination.

Clones of oats interspecific hybrids and their parental forms were studied regarding electrophoretic patterns of storage proteins. Applying the method of statistical genetics genetic differentiation of 88 lines in two combinations A.strigosa x A.sativa was determined. For the combination К-4481 х Bingo 4 significantly different groups with the similarity level not increasing 78% were identified. In the combination K-1938 х Lidia 46 lines out of 49 ones form 5 groups with the genetic similarity level equal to 80 %.

The paper presents the results of the study of common millet samples of different ecological and geographical origin from the VIR’s world collection in order to identify the sources of economically important traits for targeted use in breeding in the Republic of Belarus. As a result of the conducted research 32 sources of economically important traits (early ripeness, short stems, resistance to lodging, large grains, tassel productivity, resistance to loose smut) were identified.

The paper deals with the results of the assessment of blue lupine (Lupinus angustifolius L.) initial material using marker analysis of genes responsible for the demonstration of one of the most important economically valuable traits “seed alkaloid content”. The publications are analyzed on the creation of samples with a low alkaloid content, conception of bitter-sweet forms of lupine and possible directions of utilization of blue lupine genotypes in agriculture. The importance of the conducted research with the application of molecular-genetic methods to increase the efficiency of breeding is shown. The samples with the low alkaloid content trait are identified, which are important for breeding on the territory of the Republic of Belarus.

The article describes 12 new intraspecific taxons of yellow lupine (6 species, 5 subspecies, 1 form). The directions of their use in breeding of white-flowered varieties of yellow lupine are discussed.

The paper states the results of hybridological analysis of the trait “reduction of sympodial branching” of blue lupine. The references and own data on genetics of the indicated trait are summarized. Further directions of breeding of blue lupine intensive varieties are discussed.

The article states the main findings in breeding of blue lupine intensive varieties. The totally new direction in blue lupine breeding is described related to the creation of a capituliform plant with a fascinated stalk and blocked branching. It is pointed out that the existing gene pool enables to develop capituliform varieties with the potential yield that amounts to 14-16 t /ha of dry biomass and 7-9 t /ha of seeds.

The collection and breeding material of soybeans used for mowing is studied under the conditions of the southern zone of Belarus. The traits that enable to refer the variety to a certain group of use (for mowing or for silage) are identified. The most promising soybean samples regarding important breeding traits are identified: Malvina, Donskaya 9, Chera, Smolyanka, Madison, Vasilkovskaya, VNIIOz-31, Graill. Soybean hybrids with high economic indicators are determined: grain yield (02-1/18, 03-1/18, 03-2/18) and fodder productivity (01-1/18, 02-2/18, 03-1/18).

Embryogenic capacity of winter rape samples of different origin is studied. Variety specificity for the given trait is determined and the most promising varieties are identified. It’s established that cold pretreatment of donor plants and a type of inflorescence, from which explants are extracted, have the greatest effect on the increase of embryoid output. Cold pretreatment of selected donor buds increases embryoid output, however it is less effective than cold pretreatment of donor plants. It’s identified that the optimal period for selection of donor material is 12-20 days from the beginning of winter rape budding.

The paper presents the results of the research on the creation of the new initial material for winter rape breeding with the use of interspecific hybridization, mutagenesis and in vitro culture. It’s established that interspecific hybrids of rape have a lower embryogenic and regenerative ability than intraspecific forms of this crop, but with the use of in vitro culture the creation of the new initial material for breeding of winter rape varieties and hybrids can be sped up by 3-4 years or 30-33 %. It is shown that genotypic specificity of the initial material, pollen in anthers at the stage of mononuclear and double nuclear microspores as well as selection dates and ways of pre-treatment of the donor material are of great importance among the key factors of increasing the efficiency of in vitro androgenesis in rape.

кандидат с.-х. наук

The degree and nature of heterosis manifestation of winter rape hybrids F₁ obtained due to crossing inbred lines of domestic breeding were studied under the conditions of a field experiment. Heterotic effect and degree of phenotypic dominance of the following quantitative traits were identified: plant height, height of the primary lateral branch, length of the central raceme, number of primary branches, number of pods on the central raceme, number of seeds per pod, total number of pods per plant, seed size, performance of one plant. Promising recombinants were selected. The obtained hybrid combinations and best sources of economically important traits will be used in breeding.

The paper presents the results of the two year research on the F₁ hybrid of spring rape obtained due to crossing short-stemmed and medium-grown varieties (lines) and samples differing in the origin of parental forms. The inheritance pattern of the trait “plant height” is shown, correlation dependence is identified, the manifestation of true and competitive heterosis regarding crossing combinations is established. It’s identified that the trait “plant height” of the F₁ hybrid of spring rape has a greater correlation with the branching height (r=0.65) and the number of primary branches (r=0.59). Using system crossings of dwarf parental forms of different ecological and geographical origin dwarf lines have been identified, which are recommended for breeding for reducing the plant height in order to increase the resistance of spring rape varieties and hybrids to lodging.

The article demonstrates the analysis of productivity and environmental adaptability of winter rape varieties of Belarusian breeding. The varieties Severin (indicator of yield stability=198.2; stability index=3.5; d=27.5 % and V=13.7 %) and Zolotoi (indicator of yield stability=195.7; stability index=3.4; d=32.3 % and V=14.2 %) are characterized by the highest stability, stress resistance and a wider range of adaptable capacities. The varieties Imperial and Onix have higher indicators of the yield potential (75 and 67.1 dt/ha) and the degree of variability (V=25.1 and 27.0 %. It’s established that the variety Severin has a strong correlation (r = 0.73) between the yield and 1000 grain weight and the variety Lider has a medium correlation (r = 0.59). The varieties Vitovt, Nikolai (4.96 g), Imperial (4.88 g) and Zenit (4.86 g) have the highest 1000 grain weight.

The paper presents the results of the research on collection accessions of winter rape (60 pcs) of different ecological and geographical origin in relation to a set of economically important traits in order to identify the sources and donors for further use in breeding in the Republic of Belarus. According to the findings the following samples were identified: №46/15, №24/15, №38/15, Cu Cabeo – with regard to a high yield; №20/15, Artoga, №46/15, Anderson – with regard to the 1000 grain weight; №53/15, №55/15, №2/15, Sitro and №6/1 – with regard to the number of pods per plant; №32/15, №7/15, Typhoon, №38/15, Kodiak, №29/15, ES Neptun and №58/15 – with regard to high overwintering; and samples №25/15, №34/15, №18/15; №15/246, № 19/15, №57/15, №6/15, №9/15, №58/15 resistant to Leptosphaeria maculans.

The paper presents the results of the research on the impact of CMS (cytoplasmic male sterility) type on valuable breeding traits of hybrid combinations obtained due to test crosses between breeding samples and a tester with known CMS type. The trends towards variation of traits based on sterile M-and C-types of cytoplasm are identified. Specifics of interrelation of hybrid genotype, cytoplasm type and conditions of the research year are demonstrated in terms of definite hybrid combinations.

The paper presents the results of the assessment of maize initial material (constant selfpollinated lines of different genetic origin) in respect of individual response to phytotoxicity of herbicides. Varietal specificity of maize self-pollinated lines in relation to definite active ingredients of herbicides is determined, promising sources of resistance are identified. Optimal schemes of herbicides application for chemical weeding of hybridization plots and propagation of parental forms of Belarusian maize hybrids are recommended.

The article states the results of the study of maize initial material (100 breeding samples) in terms of the reaction to different CMS types. The initial material is classified in accordance with the reaction into C and M types of maize: 32 sterility fixers and 7 fertility restorers of CMS C-type, 7 sterility fixers and 57 fertility restorers of CMS M-type are identified. The possibility to use sterility fixers and fertility restorers of different CMS types in breeding programs on transferring seed production of hybrids to sterile basis is established.

The paper demonstrates the results of the research on sunflower breeding material in terms of genotypic differences and establishing the interrelation between molecular, phenotypic divergence  and yield of first generation hybrids. Storage protein electrophoresis technique and Nei’s-Li’s and Mahalanobis genetic distances calculated in terms of phenotypic traits can be applied for identification and classification of sunflower self-pollinated lines. Hybrids with a higher yield were obtained due to crossing lines, differing in morphological and genetic traits.

The results of a comprehensive study of the collection of sugar sorghum are presented. Economically important traits of variety samples were evaluated. The study of the collection material of fodder sorghum enabled to select 6 samples with a high productivity of dry matter and 4 early ripening samples. A significant variation of the key economically important traits was identified, which allowed using them in breeding for the creation of new varieties and hybrids.

The paper states the results of the research on 20 samples of fibre flax of domestic and foreign breeding (10 samples per group), correlations between the length of the primary root system and its weight with some economically important traits against different backgrounds of mineral nitrogen (18 kg/ha of active ingredient and 35 kg/ha of active ingredient). The samples of fibre flax with high positive correlations between these traits are identified.

The paper presents the results of the evaluation of 42 fibre flax collection accessions for flax retted stalks yield and adaptability parameters. The accessions with a high yield of flax retted stalks exceeding the control by 24.5-105.4 g/m² are identified: Snezhok (Russia) – early ripening, B-168 (Lithuania) – mid-ripening, Heiya 8, China 1 ТМР1919 (China), Saldo×Rodnik, Tonus, Soyuz (Russia), Мiandr and Yesman (Ukraine) – late ripening. The varieties VIR-15, Saldo × Rodnik (Russia), Yesman, Polisky 4 (Ukraine), Yarok (Belarus) have the highest indicators of homeostaticity and the lowest coefficient of variation. The collection accessions Belosnezhka, VIR-15, Saldo × Rodnik (Russia), Polisky 4 and Yesman (Ukraine), which have the highest indicators of flax retted stalks yield, stress resistance, genetic flexibility, homeostaticity can be used as sources of adaptability in developing new competitive varieties of fibre flax.

The article summarizes the results of studying the samples from the oil flax collection nursery with respect to the key economically important traits in 2016-2020. The sources of high seed productivity, high 1000-grain weight, short stems (up to 60 cm), high oil content in seeds and oil yield per acre were identified. On the basis of the obtained results trait specific collections were formed in terms of productivity, 1000-grain weight, oil content and fatty acid composition of oil for further use in breeding work.

The article analyzes the influence of meteorological conditions of 2015-2020 on the main economically important traits of oil flax. A significant impact of the amount of precipitation and duration of the vegetation period on such indicators as seed productivity,1000-grain weight, oil content in seeds, oil yield per hectare of crops was established. The sum of active temperatures only affected the overall duration of the vegetation period (r = -0,647). The obtained results witness the possibility of cultivating oil flax and obtaining high yields of the crop under the conditions of Belarus.

The article presents the results of the selection of elite oilseed flax plants (on the example of the Focus variety) using the standard method (±50% M_o with regard to the height and number of pods per plant) as well as using the methods of cluster and discriminant analysis in terms of a set of morphological traits using the selection criterion ±2σ. As a result of discriminant analysis, the traits that play the greatest role in intergroup differences of variety population (inflorescence length, inflorescence weight, weight and number of seeds per plant) are identified. They enable to select plants reflecting variety’s typical nature and uniformity in the best way. The effectiveness of discriminant analysis involves increasing the number of selected typical plants of the variety by 20.9%-31.0% in comparison with the standard selection method.

The paper presents the results of phenological observation on middle-early ripening varieties and variety samples of meadow clover in relation to meteorological conditions.
Comparative evaluation of the initial material is conducted in terms of a number of economically important traits and the sources for developing high yield varieties are identified under the conditions of the north-east of Belarus. The sources of a high yield of green mass are: SL-38-0 (5.1 kg/m²), TOS-middle-early ripening (5.8 kg/ m²) and GPTT-middle-early ripening (5.8 kg/ m²); of dry matter yield: Typhoon (1.3 kg/ m²), SL-38 (1.4 kg/m²) and SL-38-0 (1.5 kg/ m²); of high foliage: Mars (47 %) and GPTT-middle-early ripening (48.5 %); of a high seed yield SL-38-0 (9.1 g/ m²) and SL-38-0 (1.5 g/ m²).

The paper presents the results of the evaluation of 28 samples of 4 melilot species of different geographical origin in respect of crude protein and coumarin content in dry matter. With regard to a set of economically important traits (high protein content, low coumarin content, dry matter yield and crude protein yield) three samples of white melilot (Meshcherski, Skorospely and Omski-3), one sample of yellow melilot (Malokumarinny k-36675) and one sample of volzhski melilot (Dikorastushchi k-11455) are identified. The use of the identified sources in breeding will allow developing high yield melilot varieties with high fodder values approved for use on the territory of the Republic of Belarus.

The evaluation of green mass yield and seed productivity of Festulolium pratensis and Festulolium arundinacea was carried out on the artificial fusarium background. The variety samples of two festulolium species of fescue morphotype were involved in studying in order to identify the reaction to pathogene influence and select the plants with the highest resistance to root rots. As a result of the use of the artificial fusarium background it was identified that promising variety samples of festulolium were tolerant to Fusarium in respect of the ratio of the obtained indicators of feed mass yield, which were close to figure one on the infectious background and control.