A callus induction and plantlet regeneration system for croftonweed was developed by studying the influence of explant type (leaf, stem, and nodal segment) and different concentrations of plant growth regulators. The leaf was a better explant for callogenesis compared to the stem. The highest callus induction frequency (87.2%) was obtained from leaf segments on Murashige and Skoog's medium (MS medium) supplemented with 0.5 mg/L (2,4-dichlorophenoxy)acetic acid and 2.0 mg/L 6-benzylaminopurine (BA), and 71.6% differentiation along with a multiplication rate of 4.1 adventitious shoots per callus was achieved with a combination of 0.5 mg/L 1-naphthaleneacetic acid (NAA) and 1.0 mg/L BA. In addition, MS medium supplemented with 0.5 mg/L NAA and 1.0 mg/L BA was the best medium for axillary shoot regeneration from nodal segments. Rhizogenesis of cultured shoots was satisfactorily obtained in half-strength MS without any growth regulators. The regenerated rooted plantlets were successfully acclimatized in soil where they grew normally without showing any morphological variation. These studies provide the prerequisite system for the development of genetic engineering in the future and propagating croftonweed rapidly for further study.

Nomenclature: Croftonweed; Ageratina adenophora (Spreng.) King & H. E. Robins. EUPAD.