YELLOW PINKS - INTERSPECIFIC HYBRIDIZATION BETWEEN DIANTHUS-PLUMARIUSAND RELATED SPECIES WITH YELLOW FLOWERS

Interspecific hybridization was carried out with the aim of transferri ng yellow flower colour from yellow-flowered carnations (2n=2x=30) and Dianthus knappii (2n=2x=30) to a white-flowered cultivar of the garde n pink, Dianthus plumarius (2n=6x=90). These hybrids were difficult to make but a small number were produced from both cross combinations. A ll the progeny from the crosses with carnations were pink but those fr om crosses with D. knappii were pale cream-yellow, with some variation in intensity between plants. Differences were observed in chromosome number between hybrids, which were either tetraploid, which is the exp ected situation, or pentaploid. Observations on pollen mother cell mei osis and pollen production in D. knappii revealed that the plants were producing unreduced (diploid) gametes at significant frequencies. Ana lysis of the flower pigments showed that the yellow flower colour of D . knappii resulted from the presence of high levels of flavone and fla vonol glycosides whereas those of yellow carnations were chalcones. Th us, the Fl hybrids with D. knappii were yellow because they contained the same pigments as D. knappii but the hybrids with the carnations we re pink due to their ability to convert chalcones through to dihydrofl avones and then to anthocyanins. (C) 1998 Elsevier Science B.V. All ri ghts reserved.