INVITRO SHOOT REGENERATION OF GLOBE ARTICHOKE FROM SHOOT APICES TREATED WITH THIDIAZURON AND FROM MATURE ZYGOTIC EMBRYOS TREATED WITH CYTOKININS

Shoot apex explants treated with thidiazuron, and intact mature zygotic embryos, have been used for the first time for adventitious shoot regeneration of globe artichoke (Cynara scolymus L.). Adventitious shoot regeneration from shoot-apex explants of cv. Argos occurred on a basic cultural medium (MS supplemented with 10 mg l-1 ascorbic acid, 0.1 mg l-1 IAA (indole-3-acetic acid), 40 g l-1 sucrose and 7 g l-1 agar) to which thidiazuron was added at concentrations between 1 and 5 mg l-1. The effect of thidiazuron was equally as efficient as that of the commonly used cytokinins kinetin (6-furfurylaminopurine) and BAP (6-benzylaminopurine). The explants initially treated with thidiazuron continued to produce adventitious shoots when subcultured onto cytokinin-free or thidiazuron-free medium, but this did not occur when kinetin or BAP was initially applied to the explants. Intact mature zygotic embryo explants, cultured like the shoot apices, produced a high number of adventitious shoots when the medium was supplemented with 10 mg l-1 kinetin or 5, 10, 12 mg l-1 BAP. The sites of shoot regeneration were limited to the basal region of the cotyledons.