PARFENYUK O. Selection-genetic methods of creation of sugar beet source materials with improved root shape parameters and technological qualities of sugar raw materials.

The thesis is devoted to the improvement of selection-genetic methods and creation of sugar beet source material with improved root shape parameters and technological qualities of sugar raw materials for selection of competitive hybrids on the basis of CMS. The effectiveness of the developed schemes of the selection process for the creation and practical use of new source material (O-type lines, their analogues with CМS and diploid multi-shoot pollinators) with improved root shape and technological qualities of sugar raw materials in sugar beet selection for productivity has been experimentally proved. The possibility of using fodder beets as donors of valuable selection and genetic traits to increase the productive potential of sugar beets has been proved. It is established that the use of sugar-fodder beets in the selection of recombinant materials makes it possible to expand the genetic potential and improve sugar beets by the manifestation of important economic and valuable traits. The nature of inheritance of morphological and economically valuable traits in plants of recombinant forms of beets has been analyzed. It is established that one of the main factors of selection increase of productivity of sugar beet hybrids on the basis of CМS is the change in the shape of their root from conical to oval-conical. Experimental sugar beet hybrids with oval-conical root shape, exceed the group standard for root yield by 17–24 %, sugar harvest and sugar yield – by 15–21 % and 15–22 %, respectively. Key words: sugar beets, fodder beets, source material, O-type lines, multi-shoot pollinators, sugar-fodder hybrid, hybridization, inbreeding, backcrosses, analyzing crosses, root shape, technological qualities, productivity.