SEED SET IN CICHORIUM-INTYBUS L BY POLLINATION OF FLOWERS DEVELOPED IN-VITRO

Formation of viable seeds of Cichorium intybus L. was achieved in an i n vitro system. Flower formation, pollination, fertilization, embryoge nesis and seed development occurred in vitro on chicory root explants on culture medium lacking plant growth regulators. After flower induct ion under a 24-h daylength treatment, the explants were transferred to a 16-h daylength at 40 mu E m(-2)s(-1) irradiance for pollination and further seed development. Negative results were obtained when root ex plants were maintained continuously under a 24-h daylength during the whole culture period. Lower seed set was obtained when the cultures we re at low irradiance. The need of a dark period and adequate level of irradiance are suggested as important factors to obtain viable seeds. The developed in vitro system can be used as a model to study the fact ors controlling the reproductive processes, and for the study of self- incompatibility in chicory.