K. Zimmer
Flowering of Begonia 'Cleopatra' is promoted by short days and prevented in long days. Similar responses give B. boweri and B. boweri nigramarga (Zimmer, 1969, 1970a). In other Begonias, e.g. in B. xtuberhybrida, tuberization occurse under short day conditions (Lewis, 1951). It could be expected therefore, that flower formation is inhibited by interruption of the dark period in the middle by night break. If the same processes, which lead to flower formation, control tuber formation too, night break in the middle of the dark period has to inhibit tuber formation too, as it was shown for Dahlias by Moser & Hess (1968). Therefore, a series of experiments was started to study the influence of night break on flowering and tuberization of Begonias.
Zimmer, K. (1973). SOME PHOTOPERIODIC RESPONSES OF BEGONIA. Acta Hortic. 31, 51-56
DOI: 10.17660/ActaHortic.1973.31.5

Acta Horticulturae