CYTOGENETIC VARIABILITY OF IN-VITRO REGENERATED HYPERICUM-PERFORATUM L PLANTS AND THEIR SEED PROGENIES

Fertile plants were regenerated from adventitious shoot cultures of Hy pericum perforatum. The plants were maintained under field conditions and after open pollination, two seed generations were obtained. Chromo some counting and flow cytometric analysis of nuclear DNA content reve aled a considerable degree of variation in ploidy levels in regenerate d plants. While the ploidy level of progenies of diploid regenerants w as stable, extensive variation was observed in seed progenies of other regenerants. Crossing experiments made under controlled conditions be tween tetraploid and diploid plants indicated that this behaviour coul d be explained by the special mode of reproduction of this species (fa cultative apomixis). (C) 1998 Elsevier Science Ireland Ltd. All rights reserved.