Inter-sectional hybrids with various ploidy levels between Primula denticulata and three varieties of P. modesta
2007
Hayashi, M.(Chiba Univ., Matsudo (Japan). Faculty of Horticulture) | Kato, J. | Ichikawa, Y. | Matsubara, N. | Ohashi, H. | Mii, M.
Reciprocal crossing was carried out between tetraploid Primula denticulata, section Denticulata and three taxa of P. modesta, diploid P. modesta var. fauriae, diploid P. modesta var. samanimontana and tetraploid P. modesta var. matsumurae, section Aleuritia. Inter-sectional hybrids were successfully obtained in all the reciprocal crosses except when P. modesta var. samanimontana was crossed with the pollen of P. denticulata. The number of hybrids obtained by using P. modesta var. fauriae as maternal parent was extremely low, whereas a large number of hybrids was obtained in the crosses when tetraploid species, P. denticulata and P. modesta var. matsumurae, were used as maternal parent. In all the cross combinations using P. denticulata as maternal parent, both legitimate and illegitimate crosses yielded germinable hybrid seeds. This suggested that in tetraploid P. denticulata heterostylous incompatibility might have decreased or had been lost at least on the female side. In most crosses, the DNA content of the hybrid was intermediate between that of the parents, except for the cross of P. modesta var. fauriae x P. denticulata, where the tetraploid hybrids were mainly produced due to the fertilization of the unreduced female gametes of P. modesta var. fauriae. These results suggest that in most of the zygotes with a lower ratio of female genome than male, development was inhibited in these inter-specific hybridizations.
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