Aim. Creation of combination-capable lines of multi-sprout pollinators of sugar beets of different levels of homozygosity, establishment of criteria for their selection based on basic productivity, reproductive capacity and hybridization potential at various stages of the selection process for the formation of parental components of hybrids on the cytoplasmic male-sterile (CMS) basis. Methods. Field (experiments, phenological observations), laboratory (to determine sugar content), measuring and weighing (to determine the crop structure), statistical (mathematical processing of research results). The research was carried out at the Tobacco Research Station of the National Scientific Center "Institute of Agriculture of the National Academy of Agrarian Sciences" in the laboratory of sugar beet breeding during the 2015–2021. The starting material was three hybrid multi-sprout populations of sugar beet Um. 17/02-1705, Um. 21/01-33 and Um. 14/05-752. Linear materials were obtained by the inbreeding method. Results. It was established that the lines of multi-sprout pollinators of sugar beets of the second-third generations of inbreeding (I2-I3) are characterized by the highest productivity. The yield of root crops exceeded the standard by 8.1–9.3%, sugar content by 8.6–8.8% and sugar collection by 16.5–17.9%. As the depth of inbreeding increases, the quality of pollen deteriorates sharply. If in the lines of the first generation of inbreeding (I1), the fertility of pollen in plants of of multi-sprout pollinators was 95.1%, then in the lines of the fifth generation (I5) it decreased to 31.0%. The number of non-viable pollen grains in them was 72.2%, seed germination was 29%. Experimental hybrids with the best performance were obtained by using as pollinators lines of the second to third generations of inbreeding. According to the complex characteristic "sugar collection", they exceeded the group standard by 19.7–21.3%. Conclusions. It has been established that for the formation of line materials of sugar beet multi-sprout pollinators, as parent components of hybrids on а CMS basis, the main criterias for the selection of valuable plant genotypes, in addition to the hybridization potential, are high level of their basic productivity and reproductive capacity. The best experimental sugar beet hybrids were obtained by using lines of multi-sprout pollinators of the second to third inbreeding generations.

Purpose. To create pollinator lines - sterility fixers and their cytoplasmic male sterility (CMS)-analogues and to study their breeding and genetic features for the development of parental components of CMS-based one-sprout fodder beet hybrids. Materials and Methods. The study was carried out at the Tobacco Research Station of the National Scientific Center "IA NAAS" (Cherkaska Oblast, Uman) in 2013–2021. Four diploid one-sprout fodder beet populations of hybrid origin were taken as the starting material. Fodder beet lines were created by inbreeding. Analyzing crossings were carried out under paired coarse calico bags. Breeding accessions were tested in accordance with a method developed by scientists of the Institute of Bioenergy Crops and Sugar Beet of NAAS. Results and Discussion. The results indicate a fairly high frequency of pollinators - sterility fixers among the one-sprout fodder beet hybrids bred in Uman. The mean across all the initial accessions was 7.5%. One-sprout hybrids KT-7105 2хmm and KZ-1507 2хmm demonstrated the highest incidence Owen type pollinators - sterility fixers. A high level of pollen sterility was intrinsic to the CMS analogues of the O-type lines derived from the initial accessions IM-3319 2хmm and KZ-1507 2хmm (99.1% and 97.0%, respectively). The highest percentage of one-sprout seeds was recorded for the CMS analogues of the O-type lines derived from hybrid accessions KZ-1507 2хmm and KT-7105 2хmm. Fifteen best O-type lines have been selected for further breeding to obtain parental components of CMS-based experimental hybrids. Analysis showed that the beetroot yields of the majority of the CMS fodder beet lines were lower than that of the check variety. CMS IM-3319/16, CMS IM-3319/34 and CMS IM-3319/49 were the only lines that yielded at the level of the check variety (80.9–83.6 t/ha), which is attributed primarily to their genetic origin. As to the dry matter content in beetroots, only lines CMS ST-4514/27 and CMS ST-4514/39 significantly exceeded the check variety; the values of the others were similar to that of the check variety. In terms of the dry matter output, except for CMS KT-7105/7, CMS IM-3319/34 and CMS IM-3319/49, most lines were inferior to the check variety. Conclusions. We found that the portion of pollinators - CMS fixers in one-sprout populations of fodder beets of different genetic origins was 3.7–11.3%. Fifteen combinable O-type lines with pollen sterility fixing of 96.2–100% and percentage of one-sprout seeds of 96.4–99.3% have been created. Their CMS analogues have been obtained. The created breeding accessions are a valuable starting material for the selection of parental components and generation of highly productive CMS-based one-sprout fodder beet hybrids