The influence of density of maize hybrids on the growth, development and productivity of plants is studied due to the three-year research conducted on sod-podzolic cohesive sandy loam soil in the central part of Belarus. It’s established that the optimal plant density is greatly determined by the genotype used under specific soil and climatic conditions and for the hybrid Jaipur (FAO 230), Amavit (FAO 180) and Allegro (FAO 250) it is 90–100 thousand plants per 1 ha, for Damario (FAO 220) – 80–90 thousand/ha. For the hybrid Amarok (FAO 220) the optimum is within the range of plant density close to 90 thousand/ha.

The paper presents the results of the research on the influence of different methods of basic soil cultivation on weed infestation and maize yield under the conditions of the Central Zone of Belarus. It was established that maize pro- vided the highest yield of green mass (441.2 c/ha) and grain (72.2 c/ha) with zero tillage after ploughing for the preceding crop. Minimizing soil cultivation reduced the yield of green mass by 0.4–15.6% and grain – by 0.1–14.4%. The reduction of that indicator was reliable only when ploughing was replaced by surface tillage and direct sowing into uncultivated soil.

Due to three-year research (2022–2024) conducted on sod-podzolic cohesive sandy loam soil in the central part of Belarus the effect of nitrogen fertilizers on protein and energy yield as well as economic indicators (net income and cost) of repeated growing maize for silage or after cereals was studied. That made it possible to identify the most productive, cost-effective options and draw conclusions for the efficient use of nitrogen fertilizers and obtaining consistently high yields of maize.

The paper presents the results of the research on the effect of growth regulators on morphological indicators and resistance of spring rape to lodging depending on the level of nitrogen nutrition and sowing dates. It is shown that the morphoregulators Caramba Turbo or Reggy, applied once at the 4–6-leaf stage (BBCH 14-16), had a more significant effect on reducing the height of plants and their branching. Double application of the growth regulators Caramba Turbo, 0.6 l/ha (BBCH 14-16) and Reggy, 0.9 l/ha (BBCH 31-33) had the maximum effect on the morphological indicators of spring rape. The highest resistance to lodging (3.4–4.5 points), in comparison with the control, was established with the application of Caramba Turbo (0.7 l/ha) or Reggy (1.2 l/ha) at the 4– 6-leaf stage and double application of growth regulators, regardless of the sowing dates and the level of nitrogen nutrition.

The analysis of the results of spring triticale breeding for 1990–2024 is presented. The efficiency of different types of crossing is demonstrated. The important role of organizing ecological breeding in the Research and Practical Center of the NAS of Belarus for Arable Farming with the Upper Volga Federal Agricultural Research Center is underlined. The characterization of new varieties of spring triticale (Gelio, Novoye, Delo), created over recent years, is given.

The paper presents the results of the research on the creation of oat breeding material with increased resistance to leaf blotch. Reciprocal crossings were carried out between the sources of resistance – the varieties Zapavet, Desnyan- sky, Rollo, Strigunok, Sunland, Neiyan 2, and susceptibility – the varieties Stralets and Tifton 6028. Dominance and overdominance of oat resistance to the pathogen in F1 (hp = 1.0–1.8) were established. The nature of F2 plants segregation on the resistance trait was shown: in hybrid combinations segregation on monogenic inheritance of resistance 3:1 and digenic inheritance of resistance 9:3:3:1 was observed. The donors of leaf blotch resistance were identified - Zapavet, Desnyansky, Rollo, Strigunok and Neiyan 2. In F4, 107 lines with a set of economically important traits were selected and transferred to the breeding department, of which 16 lines were transferred as sources of leaf blotch resistance to the National Bank of Seeds of Genetic Resources of Economically Important Plants in the Research and Practical Center of the NAS of Belarus for Arable Farming.

In the Republic of Belarus the most common diseases are helmitosporium leaf blotch and root rot, loose smut also occurs. A total of 42 strains of Pyrenophora chaetomioides, 41 strains of Fusarium spр., 15 strains of Hel- mintosporium, and 6 samples of loose smut are identified as pure cultures. The shelf life of oat loose smut spores is no more than 4 years. The optimum temperature for infecting oat seeds with root rot pathogens is 22–24 ºС with inoculation of at least 8 hours for F. culmorum and 15 hours for F. avenaceum and B. sorokiniana. The assessment of oat samples resistance to helmitosporium leaf blotch and root rot is carried out using field and laboratory infection backgrounds.

The paper presents the results of the research on the effect of herbicide application on weed infestation and rape yield in the crop rotation element. It’s established that when changing the herbicide load in the crop rotation element (maize – barley – rape) from 2.43 to 6.11 kg/ha of active ingredient, the number of weeds in cruciferous crops varies within 3–76 pcs/m², raw weight – 4.6–135.2 g/m², oil seed yield – 12.9–15.4 c/ha. The change in rape yield reaches 2.5 c/ha (19.4 %) under the influence of this factor.

The paper presents the results of the research on the effect of growth regulators on sowing qualities, field germination and yield of Siberian millet under soil and climatic conditions of the south-western part of the Republic of Belarus. It’s established that the use of Hydrohumate, 0.5 l/t is the most effective for pre-sowing treatment of Siberian millet seeds. The application of this preparation promotes the increase of field germination by 10–11 % and grain yield by 2.5–3.6 c/ha.

The article presents the results of the efficiency of fibre flax pulling methods when making retted straw using the biological method of dew retting: with simultaneous boll hackling and stem retting in one row (LK-4A + MTZ-820 – one stage harvesting); with stem retting in two rows without boll hackling (TSL-2.4 – two-stage harvesting); with stem crushing and retting in two rows without boll hackling (Depoortere – two-stage harvesting) depending on cenosis density and weather conditions.

The article presents the results of the research on the influence of types and doses of macro- and microfertilizers on the yield of broccoli seeds and biochemical composition of flower heads.

In the studies, conducted on sod-podzolic light loamy soil, the use of the complete mineral fertilizer increased the yield of cauliflower by 6.6–11.3 t/ha and the use of various types of organic fertilizers (bedding manure, vermicompost, rabbit manure) – by 3.3–3.6 t/ha, with total heads yield of 24.6–29.3 t/ha in fertilized variants and net income from the combined use of fertilizers of 1927–3295 rubles/ha with a profitability of 64–183 %. The content of crude protein in cauliflower heads in fertilized options was 19.2–20.5 %, crude fat – 1.1–1.2 %, crude ash – 8.0–8.6 %, crude fiber – 16.3–17.6 %, carotene – 1.4–1.6 mg/kg, vitamin C – 64.4–68.1 mg/100 g with nitrate content within maximum permissible concentration (900 mg/kg).