IMPROVEMENTS IN ROOTING REGENERATED SAFFLOWER (CARTHAMUS-TINCTORIUS L) SHOOTS

A continuing obstacle for regenerating safflower (Carthamus tinctorius L.) plants from cultured explants or callus has been a reliable metho d for rooting shoots. For shoots directly regenerated from primary exp lants, 76% of shoots rooted after a 7-d exposure to 10 mg/l indole-3-b utyric acid. Auxin source, concentration or exposure time did not grea tly affect root formation or morphology, but strongly affected callus production. Shoots infected with Agrobacterium rhizogenes produced mas sive numbers of fibrous roots, but shoots did not elongate or survive transfer to soil. Shoot hyperhydricity symptoms were reduced by includ ing 1 g/l activated charcoal in rooting media. The optimal protocol fo r inducing root formation consisted of a 7-d exposure to 10 mg/l indol e-3-butyric acid in root induction media, followed by incubation in me dia containing 15 g/l sucrose and 1 g/l activated charcoal for 21 d.