Photoperiodic Induction of Flowering in Black-Currant

Abstract

DURING the course of a detailed morphological investigation of flower-initiation in black-currant (Ribes nigrum) it was observed that under field conditions flower primordia are normally initiated in the axillary buds following the cessation of active extension growth of the shoot. This observation suggested that possibly flower initiation depends on the cessation of extension-growth and that treatments which bring about the latter might also induce flowering. It is known that this species grows actively under long-days but rapidly becomes dormant under short-days¹, and the following experiments were therefore carried out to test whether short-day treatment promotes flower-initiation.