Apomixis in the sugar beet reproduction system

Research on five lines of sugar beet with a tendency towards apomixis showed the presence of facultative apomicts among the studied plants (2.4%). Facultative agamospermy was detected by isozyme analysis and by nuclear DNA amount estimation using flow cytometry. Genetic segregation according to isozymes in seed progenies showed the presence of meiotic agamospermy; its probable mechanism was normal meiosis in tetraploid cells of the female archespore. The occurrence of cytologically unreduced male gametophytes was confirmed in 21% of the plants by the indirect method of determining ploidy level from the number of pore regions in mature pollen grains. These studies identified homozygotic sublines with a tendency towards apomixis, proposed for practical breeding at the Kutno Sugar Beet Breeding Company Ltd., to be included in breeding experiments as components of heterotic hybrids.