L. Lopes Coelho, K. Kuligowska, H. Lütken , R. Müller
Kalanchoë species and cultivars are produced as ornamental plants in many places in the world. The genus contains around 140 species comprising significant morphological variation, however, the number of species used for breeding is limited due to lack of knowledge of e.g., flower inducing factors. Having both parental plants flowering at the same time is vital for crosspollination; therefore, it is of significant importance to be able to control flowering time of the species of interest. The objective of this study was to control flower induction in K. marmorata and K. longiflora. K. prittwitzii was used as control species to validate treatments that consisted of combining short day photoperiod (8 h) and different night temperature (18, 12 and 6°C). While K. prittwitzii had 100% flowering for all treatments, K. marmorata only flowered at 12°C (33% plants flowering) and 6°C (25% plants flowering), and K. longiflora did not flower in any of the treatments. The decrease of night temperature delayed the growth in all species and flowering in K. prittiwitzii and K. marmorata, and the number of open flowers in K. prittiwitzii was higher at 12°C. The results demonstrate that there is a variation of the flowering stimuli in the Kalanchoë genus, and that short days are not the only factors controlling flowering. Even though short days are enough to induce flowering in easily-induced species (e.g., K. prittwitzii), cold night temperatures are required to flower-induce other species (e.g., K. marmorata). There are of course other factors limiting flower induction in K. marmorata and K. longiflora, which need to be addressed in further studies.
Lopes Coelho, L., Kuligowska, K., Lütken , H. and Müller, R. (2015). PHOTOPERIOD AND COLD NIGHT TEMPERATURE IN CONTROL OF FLOWERING IN KALANCHOË . Acta Hortic. 1087, 129-134
DOI: 10.17660/ActaHortic.2015.1087.14
flower induction, Kalanchoë prittwitzii, Kalanchoë marmorata, Kalanchoë longiflora, ornamental plant

Acta Horticulturae