Studies on the physiology of bolting and flowering in Raphanus sativus L. II. Annual rhythm in readiness to flower in Japanese radish, cultivar Wase-shijunichi

Flowering of Raphanus sativus L. (Japanese radish, cultivar ‘Wase-shijunichi’) is hastened by vernalization but non-vernalized radish could flower under continuous illumination. Days from germination to anthesis in non-vernalized plants fluctuated depending on the period of seed storage, and this fluctuation showed an annual rhythm. On the contrary, the days to anthesis in vernalized radish remained nearly constant for 2 years.