Continuous callus production and regeneration of garlic (Allium sativum L.) using root segments from shoot tip-derived plantlets

Root segments from shoot tip-derived plantlets of the garlic (Allium sativum L.) clones `DDR7099', `PI383819', and `Piacenza' were utilized as an explant source for continuous, friable callus production. The best callus production occurred on root segments initially cultured on medium with 4,5 μm 2,4-dichlorophenoxyacetic acid (2,4-D) for 8 weeks, then subcultured to medium with 4.7 μm 4-amino-3,5,6-trichloropicolinic acid (picloram) +0.49 μm 6-(γ-γ-dimethylallylamino)purine (2iP) for 8 weeks. Embryogenic, friable callus was transferred to liquid medium for 1 month and then transferred to solid regeneration medium for 14 weeks. The best shoot and root regeneration (85.3% and 35.8%, respectively) occurred on 4-month-old calli from the clone `DDR7099'. In all clones, regeneration rate decreased as callus age increased. Received: 14 October 1997 / Revision received: 26 December 1997 / Accepted: 12 January 1998