The overall status of self-incompatibility, as assessed by the rate of capsule-set after self-pollination, was investigated in the genus Calibrachoa (Solanaceae). Thirty-two species were surveyed using a total of 655 individuals collected in 102 different native populations in Argentina, Brazil, Mexico, and Uruguay. The rate of capsule-set in 278 voucher specimens collected from the same native habitats was also measured to obtain additional information to assess the degree of self-(in)compatibility. Only one species, Calibrachoa parviflora, was self-compatible (SC, autogamous) and the other 31 species were found to be self-incompatible (SI). A mixed population (SI and SC individuals in the same population) was not found. The differentiation of C. parviflora as an autogamous species is associated with a successful occupation of different (riparian) habitats within a larger range of geographic distribution compared to the rest of the species in the principally SI genus of Calibrachoa.
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Acknowledgments This work could not have been accomplished without the kind assistance of Masao Udagawa of Montevideo, Uruguay, Sebastião T. Nagase, Nobuyuki Hiranaka, Tomio Koshizawa, Hideo Ohkubo, and Roberto H. Ohkubo of São Paulo, Brazil, and Tsuguyoshi Aoki and Angel Aoki of Buenos Aires, Argentina, in surveying the natural habitats of Calibrachoa. We would like to thank Juan H. Hunziker (si) for his helpful advice on identification of species. This work was supported by the Research Fellowships for Young Scientists provided by the Japanese Society for the Promotion of Science to Tatsuya Tsukamoto.
- Petunia self-incompatibility
- South America