Ben-hod, G., Department of Agricultural Botany, Faculty of Agriculture, P.O. Box 12, Rehovot 76100, Israel
Kigel, J., Department of Agricultural Botany, Faculty of Agriculture, P.O. Box 12, Rehovot 76100, Israel
Steinitz, B., Department of Agricultural Botany, Faculty of Agriculture, P.O. Box 12, Rehovot 76100, Israel, Department of Ornamental Horticulture, Agricultural Research Organization, The Volcani Center, Bet Dagan 50250, Israel

The effects of day-length and temperature on flowering and dormancy induction were studied in Anemone coronaria L., with plants raised either from corms or achenes. An Israeli hybrid source was used (de Caen cv. Hollandia × Israeli wild type).Dormancy onset is characterized by the cessation of foliage leaf production, the appearance of leaf scales protecting the perennating bud, and leaf senescence. Dormancy was induced by high temperature and long days but increasing temperatures (from 17/12 °C to 32/12 °C) induced earlier dormancy than prolonging the photoperiod (range 8-16 h). A significant (P = 0.01) interaction was found between these factors, with smaller photoperiodic effects the higher the temperature. At 22/17 °C the critical day-length for dormancy induction was between 11 and 12 h.The transition from the vegetative to the reproductive stage appears to be an autonomous process that occurs with development in plants raised from either corms or achenes and does not require environmental induction. Photo- and thermoperiodic effects on flowering were indirect, being mediated through their influence on dormancy induction. © 1988 Annals of Botany Company.