Witloof chicory (Cichorium intybus L.) root vernalization by means of exogenously supplied gibberellic acid

Abstract

Endogenous gibberellic acid (GA) is known to play a pivotal role in the vernalization process of plants requiring a cold induction. In order to establish the effect of an exogenous GA application on the vernalization process of chicory roots, GA was applied to five cultivars (two ‘late’ types and three ‘early’ types) of witloof chicory (Cichorium intybus L.). GA was applied as leaf as well as root treatments, each at high and low concentrations. Chicon quality was subsequently measured and used as an arbitrary indicator for completed vernalization. Lateral root formation was monitored as an indicator for possible damage to the external cells of the main roots. Irrespective of GA concentration, no significant difference in chicon quality was observed with the leaf treatment, compared to the untreated control. Both root treatments, on the other hand, decreased chicon quality significantly, but, despite cultivar differences, had no effect on lateral root formation. Exogenous GA treatments, at the levels used in this study, did not enhance chicon quality and thus vernalization.