The paper presents the main directions and priorities of the National strategy of the Republic of Belarus, which reflects the current state of plant genetic resources for food and agriculture (PGRFA), analyzes factors threatening their diversity, depicts problems related to conservation and sustainable use of PGRFA, identifies priority tasks and actions aimed at improving preservation and effective use of PGRFA, strengthening human resource capacity and cooperation in the field of plant genetic resources at regional, national and international levels.

The article reflects the issues related to the establishment and formation of the National Bank of Seeds of Economically Important Plant Genetic Resources. It states the results of conservation, mobilization, identification and use of genetic resources for creation of new high yield national varieties and hybrids in order to ensure food security of the country.

The article analyzes the changes in the heat supply of the autumn vegetation period of winter cereals for the period 1996–2020 in comparison with its heat supply according to the climatic norm of 1940–1970. It is shown that the calendar dates of the beginning of sowing of winter cereals as a result of climate warming shifted in the analyzed period by 4–10 days, and the end of sowing-by 1–5 days with a duration of 19–23 days.

The content of biogenic elements, sodium, chlorides and heavy metals in liquid manure of cattle, pig manure effluents and poultry manure was determined, and the levels of their entry into the soil depending on the chemical composition and dose load were calculated: annually on 1 ha, on average, nitrogen is delivered – 180–2407 kg, Р₂О₅ – 90– 1250 kg, К₂О – 73–1971 kg, СаО – 45–713 kg, MgО – 29– 594 kg, organic matter – 2,1–55,0 tons. Sodium аdmission is 7–743 kg/ha, chlorides – 13–668 kg/ha, Fe – 4–161 kg/ha, Zn – 0,4–20 kg/ha, Mn – 0,9–14 kg/ha, Cu – 0,2–6,9 kg/ha, Ni – 21–737 g/ha, Co – 6–138 g/ha, Cr – 20–985 g/ha, Cd and Pb – no more than 38 and 257 g/ha respectively.

The article presents the results of a study on on rates (90–120 kg/ha), methods (scattered and local) and timing (in pre-sowing cultivation, sowing, additional fertilizing in 5–6 or 7–8 leaves) of urea application. It is established the highest yield of dry matter and grain are formed in the variants with 30 kg/ha of nitrogen in the basic application and 60 or 90 kg/ha in the phase of 7–8 corn leaves in a scatter way. There may be other options for using urea, since the yield reduction is equivocal, with the exception of the application of 30 kg/ha of nitrogen with side-dressing of N60 in 7–8 leaves.

It is possible to increase significantly the yield and reduce the cost of fertilizers by optimizing the mineral nutrition of plants, the combined use of macro-, micro nutrient elements and growth regulators. On average over 3 year research (2014–2016) foliar fertilizing with the application of Nutrivant plus against the background of higher doses of N₁₃₀P₉₀K₁₅₀ with a consumption rate 2,0 kg/ha and triple cultivation of medium-late Vektar variety during the period of flowering-wilting increased photosynthetic potential up to 0,810 million m²/ha day, and the net photosynthesis productivity decreased at a slower rate than in other option. All this contributed to the high yield of potato tubers in this embodiment (41,8 t/ha) option.

The results of three years of research on the effect of pre-sowing protection of seeds from pests and diseases on their germination ability, plant survival and yield of corn are presented. It has been revealed that the insecticide disinfectants Tabu, WSC (imidacloprid, 500 g/l), 6 l/t and Poncho, SC (clothianidin, 600 g/l), 7 l/t show higher biological and economic efficiencies than Leatrin, SC (аcetamiprid, 300 g/l), 6,3 l/t and Tabu super, SC (imidacloprid, 400 g/l + fipronil, 100 g/l), 6 l/t, and the fungicide disinfectant Maxim XL, SC (fludioxonyl, 25 g/l + mefenoxam, 10 g/l), 1 l/t than Vershina, SC (tebuconazole, 30 g/l + azoxystrobin, 22 g/l), 1 l/t, and Vial-TT, WSC (tebuconazole, 60 g/l + thiabendazole, 80 g/l), 0,5 l/t.

Under conditions of small-plot trials the influence of the herbicide Cornegy, SE (terbutylazine, 250 g/l + 2,4-D acid in the form of 2 ethylhexyl ether, 80 g/l + nicosulfuron, 30 g/l) on corn crops has been studied by application at 3–5 leaves of the crop. The herbicide Cornegy, SE (1,5–2,0 l/ha) effectively has suppressed the annual and perennial grass and annual dicotyledonous weeds. In 2019, the death of weeds in a month after treatment has made 94,5–98,8 %, their vegetative mass decreased by 91,2–99,0 %, the kept corn grain yield has made 79,1–99,8 ctw/ha, in 2020 – 91,8–96,4 % and 97,4–98,7 % accordingly. The kept corn grain yield has made 53,7–57.9 ctw/ha.

The article presents the results of studying the resistance of the collection of spring barley to netted spotting (Pyrenophora teres Drechsler). A direct dependence of the development of the disease on the amount of precipitation and air temperature has been established. The correlation coefficient (r) between the amount of precipitation and the development of the disease was 0,96–0,99 (direct relationship), and between the air temperature and the development of the disease in the range –0,48 – –0,62 (feedback). A reliable direct correlation was established between laboratory (benzimidazole method) and field (infectious background) assessment. The correlation coefficient was in the range 0,59–0,88, which indicates a high reliability of the relationship. Sources of resistance to barley netting are identified: Linus, Nutans 3291, Chelyabinskiy 95, Mik 1, Berkut, Dzivosny, which retain the resistance trait both at the initial stages and throughout ontogenesis.

The biological effectiveness of the fungicide Hecate, OEC (0,4–0,7 l/ha) when applied three times («pink bud», end of flowering, «hazelnut») in relation to apple scab was 38,3– 93,7 %, and for scab on fruits – 17,2–94,4 %. The drug reduced the development of phyllostictosis by 60,8–100 %. The use of the fungicide Hecate, OEC at the rate of 0,4–0,7 l/ha made it possible to significantly increase the apple-tree yield by 2,26–3,81 т/ha.

The paper presents the results of a study on the effect of nitrogen fertilization on the fiber content in the trust and the yield of products when cultivating flax on sod-podzolic sandy loam soil. With the content of organic matter in the soil 1,6–1,8 %, the optimal dose of nitrogen fertilizer was set at 30 kg/ha, which ensured the yield of trusts 45,1 c/ha, fibers 14,2, including long 8,4 c/ha, the profitability of flax cultivation is 46 %. With an increase in the dose of nitrogen fertilizer to 45 kg/ha, a decrease in the fiber content in the trust, the number of the trust and the profit was established with a profitability of no more than 12 %.

The results of the analysis of the long fiber content and its quality in 60 samples of the collection of various ecological and geographical origin for 2018–2019 are presented. It was found that the high quality of the fiber, determined by its number, can form samples of flax with Belarusian and Lithuanian origin. Samples from Russia and France are not significantly inferior. The lowest number of long frayed fiber was observed in samples of flax of Ukrainian origin, which hinders their use for obtaining hybrids with high indicators of fiber quality.