Brassica campestris L.: Floral Induction by One Long Day.

A strain of Brassica campestris L. responds to a single photoinductive cycle 4 days after sowing. Extending the photoperiod from 8 to 22 or 24 hours, with incandescent light of 538-lux intensity, induced inflorescence in 90 percent of the plants. Inflorescence development was visible on dissection 5 or 6 days after photoinduction. Floral induction increased with duration and intensity of the supplementary light.