Mahmoud Inas Mohamed Ali author Hassanein Anber Mahmoud Ahmed author text journal article 2018 In vitro propagation of Rosa hybrida, L. cv. 'Eiffel Tower' was improved by the addition of thidiazuron (TDZ) and silver nitrate (AgNo₃) to the culture medium. The combination of auxin and cytokinins was indispensable for inducing response from leaf discs. Maintaining cultures under dark was better than light for callus formation and quality. The source of explants was vital in the regeneration process wherein situ explants produced callus while, in vitro explants regenerated somatic embryos and shoots. Gibberellic acid (GA₃) had a favorable effect where in vitro explants showed somatic embryogenesis with no shoots on media containing TDZ however, 37% of explants regenerated shoots directly on medium containing GA₃. The presence of benzyl adenine (BA) was essential for shoot elongation, and indole butyric acid (IBA) was better than indole acetic acid (IAA) for rooting. The optimum conditions produced rooted plants from leaf discs within ten weeks. The reported results clarify factors controlling in vitro regeneration of R. hybrida, and provide a rapid protocol allowing further improvements of rose. Rosa hybrida; leaf discs; embryogenesis; organogenesis; direct regeneration 10.17221/12/2017-HORTSCI https://hortsci.agriculturejournals.cz/artkey/hor-201802-0005.php https://hortsci.agriculturejournals.cz/artkey/hor-201802-0005.php continuing 45 2 83 91 2018 0862867X periodical academic journal