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記述言語：英語  

DOI： 10.1007/s10681-009-9955-y

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記述言語：英語   出版者・発行元：SPRINGER  

A triploid hybrid, which was obtained from interspecific crosses between tetraploid Primula denticulata (2n = 4x = 44) and P. rosea (2n = 2x = 22), successfully produced 11 plants by backcrossing with pollen of tetraploid P. denticulata. Analysis of ploidy level using flow cytometry and chromosome counting in the 11 BC(1) plants revealed that all progeny had much larger DNA contents and chromosome number than both parents. In this triploid-tetraploid (3x-4x) crossing, progeny was predominantly true or near pentaploid presumably produced by the fertilization between true or near triploid female gamete produced from triploid hybrid and diploid pollen of tetraploid P. denticulata. These results suggest that unreduced (3x) or near triploid female gametes were partially produced by single step meiosis, either first-division restitution or second-division restitution process. The zygotes formed by the fertilization between true or near triploid egg produced by single step meiosis in triploid hybrid and diploid pollen produced by normal meiosis of tetraploid P. denticulata might be the only survivors in embryogenesis.

DOI： 10.1007/s10681-009-9955-y

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記述言語：英語   出版者・発行元：JAPANESE SOC BREEDING  

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. fouriae 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.

DOI： 10.1270/jsbbs.57.165

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記述言語：英語   出版者・発行元：HEADLEY BROTHERS LTD  

Inter-section hybrids were successfully obtained from reciprocal crosses between tetraploid Primula denticulata (section Denticulata) and diploid P rosea (section Oreophlomis) by applying ovary culture 4 weeks after pollination. Differences in ploidy levels were found in these hybrids by flow cytometric analysis and by counting chromosome numbers. When P denticulata was used as maternal parent, all the hybrids were triploid, with two genomes of R denticulata and one genome of P rosea. In contrast, when P rosea was used as maternal parent, two genome-type hybrids were obtained: one was a triploid hybrid, with the same genome combinations as those obtained when P denticulata was used as maternal parent, and the other type was a tetraploid hybrid with two genomes of each species. These results suggest that unreduced (2x) gametes were formed only in the female side of P rosea.

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