Influence of the winter rape hybrids rosette development on its productivity and winter resistance

Purpose. In order to accelerate the breeding process for the creation of competitive domestic varieties and hybrids of winter rape, a research on the influence of the size of the rosette of plants in autumn on winter hardiness and productivity for early detection of promising winter rape hybrids based on cytoplasmic male sterility was conducted. Methods. As the initial material cultivars, hybrids, lines of individual selection and in-breeding obtained at the Institute of Feed Research and Agriculture of Podillya of NAAS, collection samples of domestic and foreign selection of winter rape were taken. For the study, 47 genotypes of winter rape, which were used in 2014-2015 as parents for pollination with a form of cytoplasmic male sterility (CMS), obtained from the Uman National University of Horticulture were also selected. Results. The studies were carried out in 2015-17 on the experimental fields of the Institute of Feed Research and Agriculture of Podillya of NAAS on crops of first-generation hybrids to search for a monogenic fertility restorer and sterility fixer on a sample of winter rape with cytoplasmic male sterility of the CMS ogura type. It was found that the size of the plant rosette in hybrids in autumn positively strongly correlated with the level of seed yield (2016 – r = 0.975; 2017 – r = 0.974) and from weakly positive to negative – overwintering (r = 0.091 and r = -0.159, respectively). Conclusions. It was found that the hybrids reacted differently to the overwintering conditions, which indicates the genetic ability of rapeseed hybrids to tolerate low temperatures and a complex of unfavorable environmental factors. For the creation of winter-hardy varieties and hybrids, the rosette size indicator is not decisive for the selection. It will only be effective for diagnosing the level of seed yield of winter-hardy hybrids.