Purpose. Reveal varietal features of formation grain sorghum yield structure elements depending on inter-row spacing and fertilizing doses of nitrogen fertilizers. Methods. Laboratory, field, statistical. Results. Data on features of structural elements formation and productivity of grain sorghum in dependence on varietal characteristics, inter-row spacing and level of mineral nutrition are presen­ted. An important indicator for plant productivity formation is productive tillering, since grain sorghum, like most cereals, has the ability to tiller, which under favourable conditions allows forming up to 25–45% of yield on the side shoots. In our case, sowing of grain sorghum with sowing rate 190 thousand pcs./ha and inter-row spacing 35, 50 and 70 cm, respectively, we got the same plant nutrition area – 526 cm2; the distance between plants in the row is 15, 10.5 and 7.5 cm, respectively. The average number of grains per panicle in the sorghum hybrid ‘Lan 59’ according to the experiment was 866.9 grains, but the maximum values were observed with inter-row spacing 70 cm and fertilizers N60P60K60 + N40 – 1035.1 pcs. In hybrid ‘Brigga F1’, on the average in the experiment was 554.3 pcs. grains/panicle, and with inter-row spacing 70 cm and fertilizing by nitrogen fertilizers N20–60, respectively 595.7 – 602.4 pcs. We obtained similar indicators in hybrid ‘Burggo F1’ and fertilizing rate N60P60K60 + N40 – 961.7, but on average, in the experiment, the hybrid formed 858.6 pcs. grains/panicle. Mass of grain from one plant allows fully evaluate individual productivity of plants of studied hybrids. The best indicators of grain mass per plant were obtained with inter-row spacing 50 cm and fertilizing rates N60P60K60 + N60. So, on average, in the experiment in hybrid ‘Lan 59’, 41.2 g of seeds were formed per one plant, in the hybrid ‘Brigga F1’ – 63.4 g, in the hybrid ‘Burggo F1’ – 64.0 g. The best weight parameters of 1000 seeds were obtained with the inter-row spacing 50 cm and fertilizing rates N60P60K60 + N60, that is, ‘Lan 59’ – 37.3 g, ‘Brigga F1’ – 37.4 g, ‘Burggo F1’ – 30.2 g. Conclusions. Changes in inter-row spacing and level of mine­ral nutrition cause variability in formation of yield structural components of grain sorghum hybrids – productive tillering, number of panicles per hectare, number of grains per panicle, mass of grain per plant, mass of grain per panicle and mass of 1000 seeds, which determine individual productivity of plants.

Purpose. To define morphological peculiarities of the different types of shoots of switch grass (Panicum virgatum L.) in the context of introduction in the Right-Bank Forest-Steppe and Polissia zones of Ukraine. Methods. Morpho-physiological and ontogenetic analysis, morphometric technique, statistical evaluation. Results. It was found that P. virgatum plants were producing the following types of shoots: vegetative-generative short or long rhizomatous ones (they appeared as in the underground part of a maternal shoot in «the area of shortened internodes» and in the base of its aboveground part); vegetative underground and aboveground ones (they are forming both in the axils of scales of the underground part of a maternal shoot and in the axils of cauline leaves); generative aboveground shoots (borne in the axil of cauline leaves). Morphological parameters and features of morphogenesis of reproduction, resting and secondary buds have been described. Conclusions. During flowering phase of maternal shoot, P. virgatum reproduction buds were on the organogenesis phase I–II, their bursting occured after maternal shoot has flowered. The correlation of internodes length, leave blades and sheaths has been established. The maximum values of the above parameters were observed in the middle part of the prefloral zone of the stem. In the context of introduction, panicle earing came in the third decade of July, flowering began in the first decade of August. It was revealed that complete flowers are bloomed faster than the staminate ones.

Purpose. To make comprehensive assessment of introduced oat samples of various eco-geographical origin under the conditions of the Forest-Steppe zone of Ukraine for the set of productivity and adaptability indices in order to define the most valuable ones and describe them. Methods. Field study, laboratory analysis, generalization. Results. The authors presented results of the study, evaluation and description of 35 new samples of oats from 5 countries for productivity and adaptability traits during 2011–2015 in Ustymivka Experimental Station for Plant Production to be run by the V. Ya. Yuriev Institute for Plant Production of NAAS. In field and laboratory conditions, the following indicators as yielding, productivity, thousand-kernel weight, early ripening, height of plants and length of panicle, lodging resistance were stu­died. Conclusions. A set of studies of new oat samples under various weather conditions allowed to identify material with increased parameters of economic and biological characters. During studies, it was found that ‘Laima’, ‘Stendskaia Darta’ (Latvia), ‘Borowiak’ (Poland), ‘Faks’ (Belarus) were the high-yielding varieties. Panicles in such oats samples as ‘Cwal’, ‘Borowiak’ (Poland), ‘Iakov’, ‘Mutika 1077’, ‘Mutika 990’, ‘Irtysh 22’, ‘Pokrovskyі 9’ (Russia), ‘Faks’ (Belarus), ‘Stendskaia Darta’, ‘Stendskaia Mara’ (Latvia) contained a large mass of grains (more than 2,5 g), panicle productivity in these samples was rather high both due to increased amount of grains in it and at the expense of thousand-kernel weight. Analysis of the study results showed that introduced oat samples of various eco-geographical origin were adapted to the Southern Forest-Steppe zone and can be recommended as an initial material in breeding for increasing productive and adaptive capacity.

Purpose. To reveal the features of agrobiological parameters formation of sweet sorghum various varieties and hybrids in the conditions of the Right-Bank Forest-Steppe of Ukraine. Methods. During 2018–2020 twenty-one varieties and hybrids of sweet sorghum of various ecological and geographical origins (Ukraine, Russia, USA, France, Germany, Hungary, Brazil) were studied in the field. Parameters like plant height and indices of their individual productivity (grain weight per panicle, 1000 grain weight, etc.), yield of dry biomass and grain, content of sugar in juice and protein in grain, as well as estimated sugar and protein yield in a crop. The counts were carried out in the phase of physiological ripeness of the culture. Results. In the group of Ukrainian varieties and hybrids, the plants were from 272 to 306 cm high, in the foreign group – from 274 to 412 cm. Varieties ‘Red Amber’, ‘Sioux’, ‘Affas CJ 899’, ‘Freed’ and ‘Early Orange’ are of high value for breeding practice, their plants were the tallest – from 388 to 412 cm. The panicle length of sweet sorghum cultivars of Ukrainian breeding ranged from 16.0 to 17.3 cm, foreign – from 11.0 to 19.4 cm. Grain weight from one panicle varied from 32.8 to 41.6 g and from 29.2 to 43.5 g, respectively. In a wide range, depending on the varietal characteristics, the indicator of the number of grains per panicle also varied from 1338 to 1708 pcs. The mass of 1000 grains of sweet sorghum ranged from 28.0 to 31.0 g in varieties and hybrids of Ukrainian breeding, in foreign ones – from 19.3 to 31.0 g. The yield of dry vegetative mass of cultivars of Ukrainian breeding was at the level of 8.24–9.11 t/ha. The highest rates were shown in hybrid ‘Mamont’ and ‘Huliver’ variety – 9.05 and 9.11 t/ha, respectively. For cultivars and hybrids of foreign breeding, this indicator varied from 7.00 to 12.17 t/ha. Significantly higher biomass in comparison with the standard variety (‘Sylosne 42’) was produced by ‘Vorai Sumac’, ‘Sorgo Cucre’, ‘Sioux’, ‘Freed’, ‘Red Amber’, ‘Mohavk’, ‘Affas CJ 899’, ‘Early Orange’ – 9.03–12.17 t/ha. The sugar content in sweet sorghum juice varied from 15.2 to 17.2%. The estimated sugar yield in Ukrainian cultivars was at the level of 0.82–0.89 t/ha, in foreign ones – from 0.72 to 1.18 t/ha. In all studied varieties it was the highest in ‘Sorgo Cucre’, ‘Sioux’, ‘Freed’, ‘Red Amber’, ‘Mohavk’, ‘Affas CJ 899’, ‘Early Orange’ – 0.94–1.18 t/ha. Conclusions. The productivity of sweet sorghum varies greatly depending on the origin of the variety and hybrid. In the conditions of the Right-Bank Forest-Steppe, in order to obtain a high sugar yield, it is advisable to grow ‘Sylosne 42’, ‘Favoryt’, ‘Troistyi’, ‘Dovista’, ‘Huliver’ varieties and ‘Ananas’, ‘Medovyi’, ‘Mamont’ hybrids. Varieties ‘Vaconia Orange’, ‘Vorai Sumac’, ‘Sorgo Cucre’ and hybrids ‘Ald Sorghum’, ‘Sioux’, ‘Freed’, ‘Red Amber’, ‘Mohavk’, ‘Affas CJ 899’, ‘Early Orange’ provide high yields of vegetative masses. Hybrids ‘Freed’, ‘Affas CJ 899’ and ‘Early Orange’ produce a large vegetative mass (11.08–12.17 t/ha), grain yield (8.00–8.15 t/ha) and a high protein content (9.8–11.3%).