Callus induction from different explants of commercial cultivars of leek, Allium ampeloprasum var. porrum L.

Callus induction was studied for three cultivars of leek (A. ampeloprasum var. porrum L.). Compact and friable callus was induced on embryo, leaf, and root explants on 16 different media. The highest frequency of compact or friable callus formation (up to 71.4%) was obtained when mature, zygotic embryos were cultured on BDS medium, containing 30-g/L sucrose, 1.0 mg/L 2,4-D and 0.5 mg/L BA. In this paper the characterization of a friable, embryogenic callus of leek is described. This callus type was initiated on immature embryos and differed in appearance from formerly induced compact, embryogenic callus. The friable callus was comprised of numerous globular embryoids. The genotype of the donor and the different explants were important parameters in the initiation of this callus type. The basal media did not influence the friable callus production.