Ratios of malic-enzyme (ME1) and glucosephosphate isomerase (GPI2) phenotypic classes were studied in agamospermous progenies of triploid sugar beet plants. It was shown that the ratio of enzymes phenotypic classes quite well accords with the calculations based on the supposition about reduplication of chromosome sites carrying alleles of enzyme loci accompanied by a loss of excessive allelic copies in the first cell division under embryogenesis. Polyteny – conditioned allelic dose increase leads to the occurrence of alleles – absent in the initial parent – at a certain frequency in the developing progeny. The notions of “meiotic autosegregation” and “mitotic autosegregation” – typical of meiotic and mitotic agamospermy, respectively, – were introduced; the term locus “polygenotype” characterizing the allelic composition of locus, number of chromosomes and a copies number of chromatides sites carrying marker-locus alleles in the cell before entering embryogenesis was also introduced
