“…These same plants would grow continuously under long photoperiods. The breaking of dormancy induced by either artificial or natural short photoperiods has been accomplished by three different treatments: A: long photoperiods (7,10,18,19,22,23,25,27); B: chilling (2,5,7,9,19), and C: application of gibberellic acid (1,3,4,6,13,14,15). Previous workers such as Van der Veen (23) and Downs and Borthwick (7) have suggested that, when leaves remain on the plant and are subjected to short days after visible growth has ceased, dormancy becomes increasingly more difficult to break.…”