Purpose. To study the influence of fractional composition of seed material on productive properties of spring rape seeds of the ‘Magnat’ variety and ‘MVM’ (‘Gladiator’) variety sample. Methods. Field investigations, laboratory tests, statistical analysis. Results. During 2013–2014, the influence of sown seeds of different size fractions (up to 2,5 g; 2,6–3,5 g; 3,6 g and more) on the indices of productivity of spring rape varie­ties was studied. It was found that over the years of study field germination of sown fractions of seeds in ‘Magnat’ variety averaged 83.5%, in ‘MSM’ variety sample – 86.7%. During the periods of seedling emergence and harvesting, the density of spring rape crops varied depending on relevant fraction of sown seeds. In the ‘Magnat’ variety, photosynthetic potential of crops ranged from 1.1 to 1.3 million m2/ha, in ‘MSM’ variety sample – from 1.2 to 1.6 million m2/ha. Depending on the seed fractions applied, ‘Magnat’ variety crops during the gro­wing season accumulated organic biomass from 2.05 to 2.36 g/m2 per day, ‘MSM’ sample variety – from 1.83 to 2.10 g/m2 per day. Conclusions. It was established that different fractions of spring rape seeds sown in the Northern Forest-Steppe zone of Ukraine affected the indices of germinating energy and laboratory germination, crop density formation, leaf surface area and intensity of photosynthesis process (crop photosynthetic potential, net photosynthesis performance). The highest indices of productivity and yield in the ‘Magnat’ variety was ensured by large-seeded fraction (3,6 g and more), in the ‘MVM’ (‘Gladia­tor’) sample variety – by small-seeded fraction (up to 2,5 g).

Purpose. Determine the effect of plant densities and the use of Organic-balance biological preparation on growth, development of photosynthetic potential and seed yield of maize lines, parental components of perspective hybrids (‘Arabat’, ‘Skadovskyi’, ‘Kakhovskyi’, ‘Azov’, ‘Chonhar’, ‘Hileia’ etc.) under conditions of drip irrigation. Methods. Field, morphometric, statistical. Results. In the flowering phase, the maximum differences in the area of the assimilation surface were observed between the maize lines and between variants using different plant densities and Organic-balance biological preparation. The largest indicator of the area of the assimilation surface was at the mid-late line DK445 for a standing density of 70 thousand plants/ha and the use of organic preparation Organic balance – 0.489 m2/plant. Organic-balance biological preparation had a positive effect on the dynamics of the area of the assimilation surface of the lines, had provide an increase of 0.04 m2/plant or 9.5% over individual phases of development compared to untreated control. The maximum value of the net productivity of photosynthesis – 6.78 g/m2 per day, was obtained from the FAO 420 line at a density of 70 thousand plant/ha, in the FAO 350 line was less by 4.3% with a maximum at a density of 80 thousand. plants/ha. For the FAO 290 line, the optimal plant density was 90,000 plants/ha. It was found that the genotype of the line with a share of influence of 81.2 and 85.2%, respectively, is predominantly influenced by the plant leaf area and the net productivity of photosynthesis. The influence of the organic preparation Organic-balance on these indicators was less and amounted to 13.3 and 12.3% respectively. The least influence on photosynthetic parameters was carried out by the density of phytocoenoses (the proportion of influence of 5.5 and 2.5%). Genotype with 82.2% share had the greatest influence on the seed yield of the lineage-parental components of maize hybrids. Part of the impact of the organic preparation Organic balance was 4.0%, plant density – 5.3%. The maximum seed yield of the FAO 290 line was obtained at a density of 90 thousand. growth./ha and organic drug treatment Organic-balance and amounted to 5.15 t/ha. The FAO 350 line showed the highest yield at a stand density of 80,000. growth/ha and treatment with organic drug Organic-balance – 5.46 t/ha. FAO 420, the highest seed yield, formed at a stand density of 80,000 plants/ha – 6.58 t/ha and treatment with organic drug Organic balance – 7.08 t/ha. Organic Balance treatment increased the seed yield by an average of 8.1%. Conclusions. Photosynthetic indicators of maize lines mainly depend on the genotype. Phytocenosis density and treatment with biopreparation have a much smaller effect. Under irrigation, the maximum seed yield was formed by the FAO 420 parent line of 7.08 t/ha. The results obtained indicate that in order to plan the production of seed material of maize lines, which are the parent components of hybrids, their genotypic features, the response to the density of phytocenoses and biological preparation with growth-stimulating action must be taken into account.

Purpose. Identify the peculiarities of the growth and development of plants, formation of productivity of sweet sorghum hybrids for different widths of row spacing, crops density and the use of the growth stimulant Vympel 2 in the zone of the Forest-Steppe Ukraine. Methods. The study used hybrids ‘Dovista’ and ‘Huliver’. The width of the row spacing was 45 and 70 cm for the density of the crops: 150 thousand pcs/ha, 200 thousand pcs/ha, 250 thousand pcs/ha. Sorghum seed treatment was carried out using Vympel 2 (0.5 l/t) growth stimulant and its additional foliar application in the tillering stage of the crop (0.5 l/ha). Results. Studies have revealed that the ‘Dovista’ hybrid has a significant potential for productivity due to a longer growing season. At different widths of row spacing and density of plants standing, the hybrid ‘Dovista’ yield exceeded the average by 3.6 t/ha of‘Huliver’ hybrid. The yield increase at the level of 7.3–13.0 t/ha was obtained in the variant of application of growth stimulant Vympel 2 at 45 cm of row spacing and changes in sowing rates from 150 to 250 thousand pcs/ha. Similar variants of experiment at 70 cm of width of row spacing ensured collection of vegetative mass of sweet sorghum at 6.7–12.6 t/ha more than in cont­rol variants. The growth stimulant Vympel 2 increased the accumulation of dry matter in ‘Dovista’ hybrid with a row spacing of 45 cm and various seeding rates by 1.3–4.3 t/ha, whereas with a row spacing of 70 cm – by 1.2–3.5 t/ha. In the ‘Huliver’ hybrid in similar experiments, an increase in dry matter was obtained at the level of 1.7–3.9 t/ha, and the application of the growth regulator ensured the collection of dry matter of sweet sorghum by 1.3–3.0 t/ha above the control variants. Total sugar content in the variants of the experiment was biased. Application of seed treatment with growth stimulant Vympel 2 (0.5 l/t) followed by foliar application in the tillering stage (0.5 l/ha) increased the content of total sugars by 0.15, but this slight deviation was within the experimental margin. Conclusions. The highest yield of green mass at a density of 250 thousand plants per hectare and seed treatment with growth stimulant Vympel 2 (0.5 l/t) + foliar application in the tillering stage (0.5 l/ha) provided the ‘Dovista’ hybrid – 98.8 t/ha, which is 5.3 t/ha more than in the ‘Huliver’ hybrid for the width of the row spacing of 45 cm. In the phase of physiological maturity of the grain, the content of total sugars in sweet sorghum was, on average, at the level of 15.0%, in the ‘Dovista’ hybrid – 15.4%, in the ‘Huliver’ hybrid – 14.7%.

The example of various varieties and hybrids of sugar sorghum illustrates the summary of study on assessing varying density of plants in crops on phonological cha­racteristics of sugar sorghum plants, carbohydrate composition of sorghum juice and yield of its plants. The completed study established that one hectare of sugar sorghum, subject to varietal characteristics and varying density of plants in crop, may provide the green weight of 40.83 до 106.87 t/ha at stem juice yield of 22,27 to 56,24 t/ha, which would contain 2.31 to 6.09 t/ha of total sugars suitable for bioethanol production in at the rate of 198.25 to 501.19 dal/ha. However, despite of higher estimate of total sugars yield and bioethanol at 300 thousand plants per ha density in crop, industrial plots would preferably have plant density in crops ranging within 200...250 thousand pieces per ha. Since higher density increases dry matter content of plants, consequentially, cellulose and lignin in stems, this may create preconditions for harvest losses due to stem lod­ ging Besides, 200 thousand plants per hectare enables to reach the highest level of photosynthesis net productivity which combines high intensity of the photosynthesis with photosynthetic activity of leaf surface.