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The content of hypericins in in vitro regenerated Hypericum perforatum plants ( R 0) and four generations of their seed progeny ( R 1– R 4) was compared. The mean content of hypericins in field-grown plants over the period 1992–2002 gradually increased under selection, and in the R 4 generation it was almost seven-times higher than that in the R 0 somaclones. Significant difference between hypericin content in diploids and tetraploids was detected in R 0, R 1 and R 3 generations. Hypericin content in four diploid and tetraploid lineages originated from a single somaclone was genotype dependent. To eliminate the influence of environmental conditions during different growing seasons, we used seeds of selected R 0– R 3 plants to derive R′1 to R′4 generations cultivated during the same years. In this case no statistically significant difference in hypericin content was found between the R′1– R′4 generations. Apomictically and sexually derived plants were distinguished by PCR using variable numbers of tandem repeats (VNTR) primers. The content of hypericins in apomictically derived progenies was compared. [ABSTRACT FROM AUTHOR]