Falatiuk L. Efficiency of recurrent selection for increased productivity in developing sugar beet hybrids

The thesis presents the results of investigations of studies on efficiency of recurrent selection for increasing combining ability by the elements of productivity of multigerm pollinators of Uladivka origin. On the basis of complex studies of starting populations by their yielding ability, sugar content, germination and germness of seed balls, a selection for improvement of these characters in progenies was carried out. Correlative relation between the characters in the starting populations and selection products were determined.On the basis of ascertainment of genetic value of pollensterile testers, the expediency of including to reccurrent selection of MS forms with high combining ability as the best analysers as well as components for hybridization in development of high-producing hybrids on line basis was proved. The type of inheritance of productivity elements in topcross hybrids was stated, frequency of occurrence of combinationally valuable genotypes of lines laid on the ancestors with different cjmbination of the characters of root mass and sugar content was determined. Empiric and theoretical distribution of frequency of utilitarian traits in top-cross MS hybrids was compared. Components of genotypical variation of yields and sugar content of MS hybrids, produced with the participation of improved pollinators and lines of the second inbred generation were studied, and their shares in the phenotypical structure of agronomic characters were determined. The efficiency of the two cycles of recurrent selection for increasing combining ability by the elements of productivity of pollinators in development of hybrids on CMS basis was shown. On the basis of the regularities found in inheritance and structure of variation of agronomical characters, improved pollinators on the line level and synthetics with the combination of high values of combining ability and increased germness of seed balls were obtained which is of great importance for the male component in heterosis breeding of sugar beet.