Bocharova M. Features of the creation of source material for breeding Lolium species in the Forest-Steppe of Ukraine.

The dissertation work presents a theoretical substantiated and new solution of the urgent problem on identifying the features of creating source material for breeding Italian ryegrass for productive longevity and perennial ryegrass for increasing fodder and seed productivity when using interspecific hybridization in combination with polyploidy, under conditions of northern part of the Forest-Steppe of Ukraine. According to the results of comprehensive assessment, in terms of lodging resistance and productivity, there were identified the best samples of perennial ryegrass, namely, short height sample 36186 (DNK) and three medium-height ones 40260 (GBR) 40268 (DNK), and 40310 (DEU). There were distinguished as the best samples of Italian ryegrass, namely, the varieties of Ukrainian breeding Leta, Andrianа 80; Drohobytskyi 1, Drohobytskyi 2, Drohobytskyi 16, wild short height forms 01/06 as well as breeding sample 41–5/05. Resulted from the analysis of forced vs. limited free pollination, forced pollination was revealed to be the most effective method, in which the maximum (11.7 %) level of seed setting was achieved by the hybrid combination of Italian ryegrass breeding sample 41–5/05 / Andriana 80. It was determined that by individual selection for marker (morphological) traits it was possible to form stable hybrid populations in the fourth generation of Italian ryegrass and perennial ryegrass. It was revealed that seed treatment with colchicines permitted to obtain fertile progeny resulted from interspecific hybridization Lolium multiflorum L. / Lolium perenne L. It was found that the hybrid combination Italian ryegrass breeding sample 41–5/05 / Andriana 80 was the most frost-resistant one, and by individual selection it resulted in two genotypes: perennial ryegrass (diploid) and (tetraploid). In 2019, the Italian ryegrass variety Berehynia was put on the State Register of Plant Varieties Suitable for Dissemination in Ukraine and recommended for cultivation in the Forest-Steppe and Polissia. In 2020 the perennial ryegrass variety Slavetna was put on to the State Register of Plant Varieties Suitable for Dissemination in Ukraine and recommended for cultivation in the Steppe, Forest-Steppe and Polissia.