THERMAL REQUIREMENTS DURING THE GERMINATION STAGE IN SOME NEW ORNAMENTAL SPECIES

The aim of this study was to identify optimal temperature for the germination phase of 8 ornamental flowering species (Browallia speciosa Hook., Cuphea ignea A.DC., Exacum affine Lehm., Gesneria (Rechsteineria) cardinalis Balf., Mimulus luteus L., Nemesia strumosa Benth., Salvia farinacea Benth., Schizanthus wisetonensis Low.). Trials were carried out in order to evaluate germinability (%) and germination energy (MGT) at different temperatures ranging from +12.5 °C to +27.5 °C (+32.5 °C in the case of Exacum affine), stepped at 2.5 °C intervals.

Temperature level exerted marked influence on mean germination time, while its influence on percentage germination induced smaller often non-significant differences. Exacum affine was shown to be the species requiring the most elevated temperature (25–27 °C) to achieve highest level of germination, while Schizanthus wisetonensis presented highest low-temperature (12–15 °C) percentage germination.
The latter species also presented a phenomenon of dormancy induced by high temperatures.
For all other species examined optimal temperature lay around 22.5 °C.

International Symposium on Agrotechnics and Storage of Vegetable and Ornamental Seeds

G. Magnani, M. Macchia, M. Mazzarri, G. Serra

https://doi.org/10.17660/ActaHortic.1994.362.24