Plant Cell, Tissue and Organ Culture 69: 35–40, 2002. © 2002 Kluwer Academic Publishers. Printed in the Netherlands. 35 Cumin regeneration from seedling derived embryogenic callus in response to amended kinetin Azza A. Tawfik 1 & G. Noga ∗ Institut für Obstbau und Gemüsebau der Universität Bonn, auf dem Hügel 6, D-53121 Bonn, Germany, 1 Department of Horticulture, Assiut University, Assiut 71526, Egypt ( ∗ requests for offprints; Fax: +49-228- 735764; E-mail: nogag@uni_bonn.de) Received 13 march 2001; accepted in revised form 3 September 2001 Key words: Cuminum cyminum, embryogenesis, explant type, in vitro, medicinal plants, spices Abstract Callus was induced from hypocotyl and primary leaf explants of cumin (Cuminum cyminum L.) seedlings on a medium with 4 μM 2,4-D alone or plus 2 or 4 μM kinetin. An embryogenic callus developed within 2 weeks after transferring the callus to medium lacking plant growth regulators (PGR). The presence of kinetin in the callus induction medium with 2,4-D enhanced both the callus proliferation and the subsequent differentiation of the embryoids on the PGR-free medium. Plumules with or without simultaneously developed roots were observed 3–4 weeks after subculturing the embryogenic callus on medium containing 0.5 or 1.0 μM kinetin. Subsequently, they were transferred onto half-strength medium supplemented with 1 μM indole-3-butyric acid (IBA) and 2% polyethylene glycol (PEG, 6000) for root induction and/or proliferation, and in vitro hardening of the regenerated plants. The survival rate ex vitro was 70%. No plants developed from the embryogenic callus continuously in- cubated on medium lacking kinetin. We concluded that kinetin is crucial for plant regeneration from the induced embryoids of cumin. Abbreviations: 2,4-D – 2,4-dichlorophenoxyacetic acid; IBA – indole-3-butyric acid; MS – Murashige and Skoog; PEG – polyethylene glycol 6000; PGR – plant growth regulators Introduction Cumin (Cuminum cyminum L.), family Apiaceae, was known to the ancient Egyptians as a spice and medi- cinal plant. It is produced in the warm regions of the world, mainly in India, China and southern Egypt. Recent studies have indicated its pharmaceutical and medicinal importance (Aruna and Sivaramakrishnan, 1996) and the antimicrobial effect of its oil extract (Shetty et al., 1994). While there has been an in- creasing demand on cumin in the recent years (Hoppe, 1996), its production is limited and has decreased (Abu-Nahoul and Ismail, 1995). Improvement of Api- aceae plants following the classical breeding proced- ure is generally slow, laborious and time consuming (Hunault et al., 1989). In addition, efforts to improve cumin have been constrained by the unavailability of genetic diversity for some desirable traits. Plant biotechnological manipulations at the cellular and mo- lecular levels may offer an efficient new approach to improve the secondary products of cumin for the medi- cinal industry, and to overcome production problems, especially diseases (Heath-Pagliuso and Rappaport, 1990; Shukla et al., 1997). Crucial for exploiting the potential of these biotechnological approaches is the capability to regenerate plants from in vitro cultured cells and tissues. The formation of somatic embryos in callus cul- tures, which was first reported by Steward et al. (1958) in the Apiaceae member carrot (Daucus carota L.), is a typical process of embryogenesis. The cal- lus induced with 2,4-D could undergo developmental processes of embryogenesis on the same medium or after transferring it to a second medium lacking plant