EMBRYO RESCUE TO OVERCOME BARRIERS IN THE INTERSPECIFIC CROSS OF HELLEBORUS × HYBRIDUS AND H. NIGER
Within the genus Helleborus comprising 22 species allocated to six sections, H. niger (Christmas rose) and H. × hybridus (Lenten rose) are the economically most important species. It would be interesting to combine the compact growth of H. niger with the flower colour and patterns of H. × hybridus. As a prerequisite for interspecific hybridisations, the Helleborus plant material of different genotypes within these two groups was characterised via DNA fingerprinting. Based on genome-wide distributed AFLP markers, genetic distances after Nei and Li (1979) were calculated between genotypes within H. niger (0.009-0.064), within H. × hybridus (0.020-0.070) and between genotypes of H. niger and H. × hybridus (0.222-0.294). Crossing barriers between H. × hybridus and H. niger were localised by observations of pollen tube growth in situ. They were found to be predominantly postzygotic. In order to overcome these barriers embryo rescue techniques via ovule culture were successfully applied. Ovules were isolated from the maternal plants five to seven weeks after pollination in most cases and then cultured in vitro. Overall, 13 hybrids of H. × hybridus × H. niger were obtained from 11,284 cultured ovules and verified by molecular DNA markers.
Meiners, J. and Winkelmann, T. (2012). EMBRYO RESCUE TO OVERCOME BARRIERS IN THE INTERSPECIFIC CROSS OF HELLEBORUS × HYBRIDUS AND H. NIGER. Acta Hortic. 961, 253-259
genetic relationship, interspecific hybrids, Helleborus, Helleborus orientalis, hybrids, ovule culture