Effects of some treatments on seed dormancy in branched asphodel (Asphodelus ramosus L.)

Branched asphodel (Asphodelus ramosus L.) is an unpalatable geophyte that has been increasing spreading in the pastures of Aegean region of Türkiye. To formulate effective management strategies at various growth phases, it is necessary to initiate the germination of dormant seeds. Preliminary experiments indicated that branched asphodel seeds germinated better in darkness than in light. Several dormancy-release techniques were tested to develop a rapid, uniform and better germination protocol for branched asphodel seeds including cold stratification at +4 and -18 °C, mechanical scarification with sandpaper, chemical scarification with sulfuric acid, ethanol or hydrogen peroxide and application of chemicals, i.e., gibberellic acid or potassium nitrate. Chemical scarification with 95% sulfuric acid (for 1 min) or 20 mM or 40 mM hydrogen peroxide (for 24 hours) resulted in the highest germination percentages (over 81.3%) and adequately reduced Mean Germination Time (MGT). While chemical scarification with sulfuric acid for 5, 15, and 30 min also reduced MGT, extending scarification duration beyond one-minute decreased germination rates. Lower germination rates with gibberellic acid treatment and increased germination with scarification methods suggest that the seeds have physical dormancy rather than physiological dormancy. Manual scarification with sandpaper achieved germination rates over 75% and reduced MGT by more than 57%. In conclusion, manual sandpaper application considered to be preferable for avoiding the adverse effects of chemical treatments while providing an acceptable germination rate.