[Epigenetic variation of the choriflowered--symflowered character in the symflowered sugar beet line SOAN-14].

The effect of 5-azacytidine on the variation of the choriflowered (CF)-symflowered (SF) character in sugar beet was studied in several generations obtained via seed reproduction. The epimutagen (5-azacytidine) significantly reduced the number of flowers in glomerate inflorescences in the year of seed treatment and in the next generation (Az1), leading to the appearance of plants with single flowers in bract axils of a flower stalk. The CF character resulting from epimutagene treatment of sugar beet seeds (plants with genotype M(Z)M(Z) was inherited as a monohybrid character in both zygotic and apozygotic seed progenies.

[Fruit set variation associated with apozygotic reproduction in sugar beet (Beta vulgaris l.)].

Fruit set upon apozygotic reproduction was studied for four years in the msSOAN-5 pollen-sterile inbred sugar beet line. The progenies obtained from pollen-sterile plants by apozygotic reproduction had both fruits with normal seeds and parthenocarpic fruits without seeds, which was not an occasional event. Growth conditions proved to strongly affect the fruit set and seed quality.

[Analysis of serial sequences of seeds in sugar beet plants upon apozygotic reproduction].

Dichotomic serial sequences of fruits of two types (with and without seeds) on shoots were analyzed in sugar beet upon apozygotic reproduction. Serial sequences were analyzed using serial statistical tests. The distribution of fruits of the two types was nonrandom in most cases.

[Embryo pathway and stem cells in higher plants].

The Weisman's conception of germ track is considered in historical context focusing on fundamental differences among germ tracks in animals and plants. Differentiation of animal germ track cells occurrs once whereas in plant ontogenesis this process is multiply realizing (a concept of recurrent embriony). Fundamental differences in morphogenesis and embryogenesis of animals and plants as well as the differences in the properties of somatic and stem cells provide plants with special and additional modes of variability and evolution which are absent in animals.