<i>In vitro</i> propagation of rare endemic <i>Tripleurospermum hygrophilum</i> (Asteraceae): Assessment of genetic stability by chromosome number and genome size

Tripleurospermum hygrophilum is a threatened rare endemic species in Türkiye. In this work, an effective in vitro propagation protocol was developed for T. hygrophilum using in vitro techniques. Nodal explants were used to test in vitro shoot induction in Murashige–Skoog (MS) medium supplemented with several combinations of cytokinins and auxins. The highest number of shoots (2.90±0.55) among all the media was obtained from MS medium supplemented 0.25 mg L−1 6-Benzylaminopurine+0.1 mg L−1 Indol-3-butyric acid. Rooting was observed in all auxin concentrations studied, while the highest number of roots (15.85±2.87) was found in MS medium containing 0.25 mg L−1 1-Naphthaleneacetic acid (NAA). The survival rate of the plants transferred to the external environment was found to be 98%. No changes in chromosome number (2n=2x=18) and genome size between regenerants and mother plants in natural population were detected. This in vitro propagation protocol developed herein can be used as conservation activites of the threatened endemic species of T. hygrophilum.