Over 250 dihaploid lines derived from a disomic tetraploid genotype of Solanum acaule ssp. acaule Bitt. (aco. PI472655) were produced via androgenesis. The anther donor plant had previously shown immunity to bacterial ring rot caused by Clavibacter michiganensis ssp. sepedonicus (Spieck and Kotth.) Davis et al., and has now been shown to have high embryogenic capacity in anther culture. In total, 370 shoots were regenerated from 4,011 anthers cultured. The ploidy level of the 287 regenerants was determined from greenhouse-grown plants using flow cytometry. Of these plants, 274(95%) were dihaploids with an average DNA content of 1.68 pg, approximately half that of the tetraploid anther donor (2.95 pg). The remainder of the anther-derived regenerants (5%) were tetraploid, hexaploid or mixoploid. Chromosome counts confirmed the results obtained by flow cytometry. In the greenhouse, none of the 33 dihaploid lines analysed produced berries but showed low (2%) male fertility. This contrasted with five greenhouse-grown tetraploid anther-derived plants which produced berries and seeds. Comparison of the general leaf morphology and floral characteristics of the tetraploid anther donor, S. acaule, and the dihaploids indicated that little variation exists in this species.
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Acknowledgements The authors wish to acknowledge Ms. Kirsti Salmi, Saija Jaakkola and Tiina Marttila for technical assistance in anther culture and flow-cytometric analyses. Dr. Jonathan Robinson is also thanked for critical review of the manuscript. This work was financially supported by the Finnish Ministry of Agriculture and Forestry.
- Anther culture
- DNA content
- Flow cytometry