FLORAL INITIATION IN STRAWBERRY AND SOME EFFECTS OF RED AND FAR-RED RADIATION AS COMPONENTS OF CONTINUOUS WHITE LIGHT

Abstract

The effects of different ratios of red to far-red radiation in continuous light on flower initiation in strawberry are described. A correlation was found between flower promotion and the content of far-red light in the supplied radiation which may be related to the red/far-red ratio of light and therefore to the level of phytochrome-Pfr in the plants. However, since relatively high energy (white) light was the only radiation used, a clear distinction between photosynthetic and red/far-red photoreversible effects is not possible. Flowering did not occur on all runner plants. Where flowering was promoted it invariably occurred first on the second- or third-formed runner plants on the stolon. Flowering was delayed on the proximal runner plants and never occurred on the mother plants. The results support the premise that a flower-inhibiting system was present along a concentration gradient in the runner.