Purpose. To establish the optimal seeding time and depth of ‘Dniprovskyi 39’ and ‘Vinets’ sorghum varieties, to prove their effect on the crop photosynthetic capacity in the Right-Bank Forest-Steppe of Ukraine. Methods. Field, laboratory, comparative, analytical, generalizing, mathematical and statistical. Results. It was proved that the best results of crop photosynthetic capacity of sorghum were obtained by sowing in the first decade of May (the second sowing period) at a seeding depth of 4–6 cm. Accordingly, the leaf surface area in these variants reached its maximum during the “panicle-blooming” period and equated 36.13–38.81 thousand m2/ha for the ‘Dniprovskyi 39’ variety and 34.23–36.91 thousand m2/ha for the ‘Vinets’ variety. By sowing seeds in the third decade of April (the first sowing period) at the seedining depth values described above the leaf surface area of the varieties was slightly smaller and amounted to 29.56–31.20 thousand m2/ha for the ‘Dniprovskyi 39’ variety and 27.76–29.40 thousand m2/ha for the ‘Vinets’ variety. By sowing seeds in the second decade of May (the third sowing period), the leaf surface area was 30.68–32.92 thousand m2/ha for the ‘Dniprovskyi 39’ variety and 29.08–31.32 thousand m2/ha for the ‘Vinets’ variety. The highest photosynthetic potential was obtained for sorghum plants in the second sowing period at the seeding depth of 4–6 cm and was 1.27 and 1.34 million m2/ha for the ‘Dniprovskyi 39’ variety and 1.16 and 1.22 million m2/ha for the variety ‘Vinets’. In the first sowing period, this indicator was slightly lower and amounted to 1.18 and 1.23 million m2/ha for the ‘Dniprovskyi 39’ variety and 0.98 and 1.02 million m2/ha for the ‘Vinets’ variety respectively. In the third sowing period, it was the smallest one and equated 1.09 and 1.13 million m2/ha for the ‘Dniprovskyi 39’ variety, and 0.88 and 0.93 million m2/ha for the ‘Vinets’ variety at the optimal seeding depth. The photosynthetic potential was lower at the seeding depth of 2 and 8 cm, which is explained by the different soil and climatic parameters during a certain period of sorghum plant vegetation. The highest value of the photosynthetic capacity net indicator was obtained by sowing seeds at the optimal time and the optimal seeding depth and it equated 3.84–4.02 g/m2 per day for the ‘Dniprovskyi 39’ variety and 3.79 – 3.98 g/m2 per day for the ‘Vinets’ variety. Conclusions. It has been established that the sorghum plants had better vegetation and formed photosynthetic capacity by sowing seeds in the first decade of May at the planting depth of 4–6 cm, which we recommend for growing this crop in the Right-Bank Forest-Steppe of Ukraine.

Purpose. To determine morphological and morphometric features of vegetative and generative organs of Persica species and varieties under the conditions of the Forest-Steppe zone of Ukraine for further use in breeding. Methods. Biological (morphological analysis) and statistical (processing of morphometric parameters) ones. Results. It was found that except ternate multiple buds, in peach hybrid ‘Suputnyk’collateral buds were prevalent which was not common to other tested varieties and species. Buds of each species and variety have a certain number of scales. The most scales were observed in ‘Suputnyk’. Pubescence of abaxial side of the leaf in P. davіdiana and ‘Suputnyk’ plants was not revealed. Species of P. vulgaris (‘Pecherskyi’, ‘Antotsianovyi’, ‘Poleskyi’) was characterized by increase in size of leaf blades, flowers and fruits. The distinctive features of P. davidiana and ‘Suputnyk’ are that stamens were accumulated in their flowers while in P. vulgaris they are branched. Raphe of a P. vulgaris stone protrudes above the edges of the bordering creases and consists of a number of narrow plates. Conclusions. For the breeding purposes, plants have an advantage for some basic criteria: the most flower buds that is common to interspecies hybrid ‘Suputnyk’; increase in photosynthetic productivity of the leaf apparatus to be typical for the variety ‘Pecherskyi’; large fruits that ‘Pecherskyi’ variety is noted for; intense red color of fruits that is inherent feature of ‘Antocianovyi’ variety.

Purpose. Comparative studies of the photosynthetic apparatus of winter wheat varieties of modern and earlier breeding in the relation to their productivity. Methods. Field, pot experiment, biometrical, gas analysis, analytical and statistical ones. Results. It is found that the modern high-yielding winter wheat varieties have a higher rate of flag leaf photosynthesis during generative period of development, particularly at grain filling period, improved ability to store assimilates in stem and effectively use them later for grain growth. The modern varieties form crop canopy with greater leaf area and chlorophyll indexes and larger photosynthetic capacity and maintain functional activity of photosynthetic apparatus longer at the end of the growing season. Conclusions. The superiority for grain productivity of modern high-yielding wheat varieties, originated from the Institute of Plant Physio­logy and Genetics, NAS of Ukraine, over varieties released before the “green revolution”, results from increased capacity and durability of functioning the crop photosynthetic apparatus, higher CO2 assimilation rate and optimization of source-sink relations in whole plant.

Chloropyll fluorescence intensity dependence on biological features of sugar beet hybrids and plant growth stages is described. Accuracy of a method of rapid diagnosis of the photosynthetic apparatus status of sugar beet plants are evaluated.

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.

In the article, on the example of different sorts and hybrids of sorgo, efficiency of the use of mineral feed is considered in technology of his growing which positively influences on the size of puff surface and it fotosintetichnu activity, promoting the productivity of plants here.

Outlook for selection on increased photosynthetic productivity of winter rye plants is discussed. Donors of short-stem resistant to powdery mildew winter rye were bred with erect and drooping shape of leaf blade. In the erect form the apexes of leaf are oriented at the angle drooping form has 45° inrelation to the stem. Incomplete domination of the drooping leaf shape with ratio 1 : 2 : 1 is established. For the first time symbolic designation of dominating genes is offered with drooping leaf blade - StSt, with transitional heterozygote Stst with recessional heterozygote stst. Higher yield of grain in the comparative variety examination was proved to be received for the erect leaf form, which is predetermined by decrease of plant height, increase of kernel weight from ear, as well as of 100 kernels from plant and by quantity of redicles. Drooping leaf blade rye forms are also promising for selection on increased photosynthetic potential.

Purpose. To determine the efficiency of growing soybean varieties ‘Ustia’, ‘Cordoba’, ‘Estafeta’ depending on the influence of microfertilizers and growth regulators. Methods. Field, laboratory. Results. The article presents the results of studying the efficiency of growing different varieties of soybeans. It was found that in the cultivar ‘Ustia’ the best values of assimilation of photosynthetically active radiation were obtained for the applications of Yara Vita Mono Molitrak in the budding phase (0.25 l/ha) with growth regulator Radostym, and Yara Vita Mono Molitrak in the budding phase (0.25 l/ha) + in the flowering phase (0.25 l/ha) with two studied growth regulators. Similar patterns of the utilization rate of photosynthetic radiation were obtained for the ‘Cordoba’ and ‘Estafeta’ varieties. According to the indicators of the energy balance, the complex use of micronutrient fertilizers and growth regulators in any case pays off with an increase in the yield, which means it is energetically expedient. The maximum coefficients of energy efficiency in the ‘Ustia’, ‘Cordoba’ and ‘Estafeta’ varieties were obtained with the introduction of micronutrient fertilizers Yara Vita Mono Molitrak in the budding phase (0.25 l/ha) + in the flowering phase (0.25 l/ha) and growth regulators Biosyl and Radostym. However, the use of growth regulators separately does not always provide an economic return on investment. In particular, in the variant without Yara Vita Mono Molitrak microfertilizer, the ‘Cordoba’ variety received 28 873 UAH/ha of net profit, while the introduction of growth regulators did not pay off, since there was no significant increase in the yield, and with the use of growth regulators Biosyl and Radostym net profit was within 28824–29179 UAH/ha. In general, the use of micronutrient fertilizer Yara Vita Mono Molitrak with growth regulators Radostim and Biosyl ensu­red guaranteed yield increase. Conclusions. When gro­wing ‘Ustia’, ‘Cordoba’ and ‘Estafeta’ varieties from an energy point of view, it is better to use Yara Vita Mono Molitrak microfertilizer in the budding phase (0.25 l/ha) with the growth regulator Radostym. Under these conditions, the obtained energy efficiency ratio was 3.24; 3.41 and 3.45, and the profit was 31503, 34072 and 34649 UAH/ha, respectively

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. Comparative studies of the photosynthetic apparatus of winter wheat varieties of modern and earlier breeding in the relation to their productivity. Methods. Field, pot experiment, biometrical, gas analysis, analytical and statistical ones. Results. It is found that the modern high-yielding winter wheat varieties have a higher rate of flag leaf photosynthesis during generative period of development, particularly at grain filling period, improved ability to store assimilates in stem and effectively use them later for grain growth. The modern varieties form crop canopy with greater leaf area and chlorophyll indexes and larger photosynthetic capacity and maintain functional activity of photosynthetic apparatus longer at the end of the growing season. Conclusions. The superiority for grain productivity of modern high-yielding wheat varieties, originated from the Institute of Plant Physio­logy and Genetics, NAS of Ukraine, over varieties released before the “green revolution”, results from increased capacity and durability of functioning the crop photosynthetic apparatus, higher CO2 assimilation rate and optimization of source-sink relations in whole plant.