The thesis summarizes the theoretical generalization, scientific justification and a new solution to the problem of producing pre-basic and basic winter wheat seeds, by increasing the yield properties and sowing qualities in the conditions of the western Forest-Steppe of Ukraine, which refers to the zone of risky seed production of grain crops.
The main limiting weather factors in recent years identified and there has been an intensive increase in temperatures above 5 °C, 10 and 15 °C, a long day at these temperatures, exceeding the sum of active temperatures, a decrease in the duration of the frost period, an increase in annual rainfall and a higher temperature regime and less amount of precipitation during the formation of seeds. The influence of these factors on seed productivity and sowing qualities of the genotype variety, which estimated at 32 %, weather conditions – 58 %, were established. There are substantiated that in the soil and climatic conditions of the studied zone the highest seed productivity was provided by the varieties: Kolos Myronivshchyny, Benefis, Shchedra nyva, Yuviliar myronivsky, Lisova pisnia, Ovidiy, Lastivka, Sluzhnutsia. The difference between Forest-Steppe and Steppe ecotypes was: by seed yield – 0.44 t/ha; multiplication factor – 3.0 units; yield of conditioned seeds – 1.9 %; mass of 1000 seeds – 4.3 g; yield of a large fraction of seeds – 6.4 %, medium – 1.5 %, small one – 4.9 %; germination energy – 1.1 %, laboratory germination – 0.3 %. The dry mass loss of 1000 grains of winter wheat influenced by the duration of grain over standing on the root resistance of the varieties to the phenomenon of enzyme-mycotic depletion of grain on the 4-th day after the onset of full ripeness in the Forest-Steppe ecotype varieties, they amounted to 1.4 %, of the Steppe ones – 2.2 %; on the 8-th day they grew to 3.9 and 5.7 %, and on the 12-th day – to 7.5 and 9.0 %.
On the background of the mineral nutrition of winter wheat plants, the effectiveness of applying the pre-sowing treatment of seeds with bacterial preparations, growth stimulators for field germination, growth and development processes in the autumn period, sugar accumulation in tillering nodes, wintering of plants are scientifically substantiated. The use of Agrobacteryn and Diazophyte ensured an increase in seed yield of 0.21–0.23 t/ha to the background of mineral nutrition N90Р90К90. The effectiveness of Polimixobacteryn was higher than 0.59 t/ha on the background of mineral nutrition N30Р90К90 + N30 in the IV and VII stages of organogenesis and 0.44 t/ha with a lower phosphorus rate (P45). The seed reproduction rate grew by 0.8–2.3 units. Diazophyte and Agrobacteryn contributed to the formation of a mass of 1000 seeds in the range of 43.6–44.0 g, Polimixobacteryn – 44.7–45.3 g. The seed germination energy and laboratory germination rate for seed inoculation variants were higher by 5–10 % and 7–11 % to absolute control and by 4–7 % and 1–3 % – to the background of mineral nutrition of plants.
The positive effect of foliar application in the phase tillering – booting on the background of mineral fertilizers in the rate N90P90K90 with the phased introduction of nitrogen in IV and VII stages of organogenesis of growth regulators and chelated micronutrients on the resistance of plants to diseases, formation of the leaf surface, net productivity of photosynthesis, and ultimately, an increase in seed productivity and sowing qualities of winter wheat seeds. The highest efficiency obtained by applying complex micronutrient fertilizers Oracle copper chelate (1.5 l/ha), Oracle biocobalt (0.18 l/ha) and Oracle multicomplex (1.5 l/ha)
The expediency of applying biologized technology for growing winter wheat seeds has been proved compared with the basic and energy saturated, for which the yield of conditioned seeds of varieties was 80–87 %, which is due to an increase in the mass of 1000 seeds and larger content of seeds of a large fraction by 6.1–11.5 %.
An economic assessment of the cultivation of pre-basic seeds depending on the studied technological measures is given.
