INTERGENERIC HYBRIDS BETWEEN SPECIES OF HYDRANGEA AND DICHROA - THEIR GERMINATION IN VIVO AND IN VITRO AND MOLECULAR VERIFICATION BY RAPD ANALYSIS

M. Wiedemann, K. Meinl, M.S. Samain, E. Klocke, S. Abel, S. Wanke
Hydrangea macrophylla (Thunb.) Ser. is a very popular pot plant with a long breeding history. The genetic background of today’s hundreds of cultivars is rather narrow because they originate from only a few progenitors. In the past, H. serrata (Thunb.) Ser. was used to widen the gene pool of H. macrophylla for breeding initiatives as well as to increase the phenotypic diversity. Molecular phylogenetic studies demonstrated the close relationship of Dichroa Lour. and H. macrophylla as well as the paraphyly of Hydrangea s.l. (Hydrangeaceae tribe Hydrangeeae), which is opening new research avenues by widening the gene pool and phenotypic variability through hybridization. We realized first crossings between H. macrophylla as well as H. serrata cultivars with D. febrifuga (Lour.) or D. yunnanensis (S.M. Hwang.). Hand pollination was performed in late spring and summer 2013 and seeds were harvested from September 2013 to January 2014. The seed set varied depending on the parental partners. Macroscopically normal developed seeds and seeds where the seed number exceeded 30 per cross-combination were sown in peat soil in the first week of February 2014. In vitro germination was applied to few seeds obtained from eight cross-combinations. The best germination rate was observed with sterilized seeds after a treatment with 1.3 mg/L GA3 and 1.0 mg/L KNO3 followed by germination on ½ Gamborg B5-medium supplemented with 10 g/L sucrose and 0.13 mg/L GA3. Plants originating from in vitro germination were successfully transferred to greenhouse cultivation. RAPD analysis performed on plants showing peculiar morphology confirmed that intergeneric hybrids between Dichroa and Hydrangea ssp. have been successfully generated by cross-breeding.
Wiedemann, M., Meinl, K., Samain, M.S., Klocke, E., Abel, S. and Wanke, S. (2015). INTERGENERIC HYBRIDS BETWEEN SPECIES OF HYDRANGEA AND DICHROA - THEIR GERMINATION IN VIVO AND IN VITRO AND MOLECULAR VERIFICATION BY RAPD ANALYSIS. Acta Hortic. 1087, 333-338
DOI: 10.17660/ActaHortic.2015.1087.43
https://doi.org/10.17660/ActaHortic.2015.1087.43
hortensia, intergeneric hybridization, molecular characterization
English

Acta Horticulturae