THE STUDY OF THE VARIETAL SPECIMENS OF SWITCHGRASS (PANICUM VIRGATUM L.) ON A COMPLEX OF USEFUL SIGNS IN THE CENTRAL FOREST-STEPPE OF UKRAINE CONDITIONS

Purpose. To study switchgrass varietal specimens (‘Zoriane’, ‘Morozko’, ‘Liniia 1307’ and ‘Cave-in-Rock’) according to economically valuable traits, and to distinguish the most yielding specimens with high yield of certified seed in relation to the weather conditions of the vegetation period (hydrothermal coefficient). Methods. Methods of scientific research in agronomy, laboratory-field method – to determine the quantitative indicators of vegetative and generative parts of plants and the weight of 1000 seeds, quantitative-weight methods – to determine crop productivity and yield of certified seed; statistical processing of research results was performed by a dispersion analysis and variation statistics. Results. Varietal specimens ‘Zoriane’ and ‘Liniia 1307’ formed the highest quantitative indicators of vegetative (height of plants, number of stems and leaves, length of flag leaf) and generative part of plants (panicle length and width, number of twigs of the first order, number of panicles and weight of seeds from panicle) independently from the cultivation conditions. Influence of biometric (quantitative) indicators of the generative part of plants, in close interaction with the weather conditions by HTC during the vegetation period, on the seed productivity, which affects the total crop yield, has been determined according to the research results. Seed yield of switchgrass varietal specimens by the determination coefficient (d) depends on: 53–59% – the number of twigs of the first order, 48–52% – the number of panicles, 12–21% – the seeds size, and 6–12% – the length and width of panicle. Conclusion. Variety ‘Zoriane’ and ‘Liniia 1307’, which form weighty seeds, high seed yield (more than 250 kg/ha) of certified seed (about 65%) have been distinguished and can be used in further breeding work to create and expand switchgrass assortment. In future, this will allow to get seed material of high quality without any additional cost as well as to establish new energy plantations for the production of plant biomass for energy purposes and additional products for various industries