POLYMORPHIC ITS AS A TOOL TO IDENTIFY HYBRIDS AND THEIR PARENTS IN CULTIVATED GENISTEAE (FABACEAE)

Internal Transcribed Spacer (ITS) of ribosomal DNA is a classical sequence used for phylogenetic analyses.
Usually, concerted evolution homogenizes the numerous ITS of an organism in such a way that a single sequence is amplified.
However, for vegetatively propagated plants of hybrid origin, several ITS sequences can be obtained from a single individual.
By cloning ITS sequences of various taxa assigned to tribe Genisteae within Fabaceae, we have been able to show such ITS polymorphism in Cytisus × kewensis, C. × dallimorei, C. × praecox, Genista × spachiana and G. ‘Porlock’ among others.
For these taxa, the distinct ITS sequences can be compared with sequences of putative parents found in literature.
We have then confirmed that Cytisus × kewensis is a C. ardoinoi × C. multiflorus cross.
We have also confirmed that Genista ‘Porlock’ is a cross between G. monspessulana and G. × spachiana. Genista × spachiana, commonly presented as G. canariensis × G. stenopetala cross may in fact be a more complex hybrid involving also G. monspessulana.