Regeneration of Trachyspermum ammi L. Sprague ecotypes via indirect somatic embryogenesis using hypocotyl and epicotyl explants

Abstract

Trachyspermum ammi L. Sprague, commonly known as ajwain, carom or thymol seeds, is one of the oldest medicinal plants with numerous health benefits. The classical breeding process of medicinal plants is not only time consuming but also requires much efforts. Biotechnological techniques such as in vitro regeneration which increase the capacity of production of medicinal plants rely upon a plenty of components. Here, we studied regeneration of T. ammi by indirect somatic embryogenesis by employing MS and B5 media supplemented with a diverse concentration of plant growth regulators (PGRs), including 2,4-D, kinetin, NAA, IAA, and BAP with four explants (hypocotyl, epicotyl, root and node) and 3 ecotypes (Qom, Yazd, and Rafsanjan). The highest callus induction was obtained from hypocotyl explants on MS medium supplemented with 8.917 µm/L 2,4-D and 2.32 µm/L KIN and epicotyl explants on B5 medium supplemented with 1.074 µm/L NAA and 0.89 µm/L BAP. The highest indirect regeneration (83%) was observed in hypocotyl explants on MS medium supplemented with 0.93 µm/L kinetin. To the best of our knowledge, the present study (2017) is the first report on indirect somatic embryogenesis from hypocotyl and epicotyl of the Iranian Trachyspermum ammi ecotypes that can be beneficial for genetic transformation and other plant biotechnology techniques.