Purpose. Assessment of foreign switchgrass varieties of foreign selection by biomass yield and seed quality depending on their maturity groups, and determination of the best varieties for the use in breeding.
Methods. Laboratory, field, measuring and weighing, mathematical and statistical.
Results. An important task of Ukrainian breeders is to develop varieties with high productivity, plasticity, resistance to stress and which would combine high biomass yield and seed quality, because without high-quality seeds, wide introduction of varieties into production is not possible. To develop such varieties, it is necessary to analyze the source material of various origins, including foreign breeding. It was found that in conditions of unstable moisture in the Western Forest-Steppe of Ukraine (Yaltushkivska EBS), the yield of raw biomass and the yield of dry biomass depended on the maturity groups of the cultivars and was the highest in the mid-early, mid-late and late cultivars. When selecting varieties for the use in the breeding process of developing new varieties for biomass production, it is advisable to take into account not only the yield of biomass, but also the quality of their seeds. Taking into account the quality of seeds and the yield of dry biomass for the Western Forest Steppe of Ukraine, the optimal varieties in which these two indicators are combined and are the highest are the early-ripening varieties 'Forestburg', the medium-early 'Sunburst', the medium-late varieties 'Morozko', the varieties 'Cave-in-rock' and "Alamo". Late and very late varies provide the same yield of dry biomass, but with an insufficient sun of effective temperatures, which is necessary for the formation of quality and ripening of seeds, their germination was very low.
Conclusions. Taking into account the quality of seeds and the yield of dry biomass for the Forest-Steppe of Ukraine, the optimal varieties in which these two indicators are combined and the highest are early-ripening variety 'Forestburg', medium-early variety 'Sunburst', medium-late varieties 'Morozko', 'Cave-in-rock' and 'Alamo'.