ISHS Acta Horticulturae 690: I International Rose Hip Conference
THE IMPORTANCE OF BEING MOTHER - INHERITANCE IN DOGROSES, ROSA SECTION CANINAE |
| Authors: | G. Werlemark, H. Nybom |
| Keywords: | apomixis, heterogamy, meiosis, morphology, pollen viability, RAPD, rose-hip |
| Abstract:
The dogroses, Rosa section Caninae, are all polyploid (4x, 5x, 6x, n = 7) with pentaploidy being most common. These species are characterized by their peculiar meiosis where only one genome is transmitted from the pollen parent while the other genomes (3, 4 or 5 depending on ploidy level) originate from the seed parent. This leads to a bias towards maternal inheritance of both molecular markers and morphological characters. A reciprocal cross between R. dumalis and R. rubiginosa showed only minor overlapping in morphological characters between the two progeny groups. Of the molecular RAPD markers, all or all-but-one of the markers were transmitted from the seed parent to the progenies. In contrast, only half of the markers were transmitted from the pollen parent. Approximately 10% of the progeny plants never received any markers from their pollen parents, thus indicating an apomictic origin. Similar results were obtained when other species combinations in this section were studied, e.g. R. rubiginosa × R. sherardii and R. sherardii × R. villosa subsp. mollis. Until now, all species except R. sherardii have produced at least some apomictically derived progeny in our crossing experiments. These results have also been further sustained by microsatellites and pollen viability studies. | |
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