Abstract
Tephrosia purpurea (L.) Pers. (wild indigo) is a leguminous plant valued for its medicinal and soil-enriching properties. However, its propagation is limited by hard seed coat induced dormancy, which restricts water absorption and delays germination. To overcome this constraint, various physical, mechanical and chemical dormancy-breaking treatments are used. The present study was conducted to assess the efficiency of different dormancy-breaking treatments on germination of T. purpurea. The study was conducted during 2021 at Dr. M.S. Swaminathan Agricultural College and Research Institute, Tamil Nadu Agricultural University, Thanjavur, Tamil Nadu, India. Tephrosia purpurea seeds were exposed to various dormancy-breaking treatments, namely heat, mechanical, chemical and growth regulator applications. The data were subjected to statistical analysis. The study revealed that dormancy in T. purpurea is mainly physical due to a hard, impermeable seed coat. Among all treatments, hot water treatment for 6 min was the most effective, resulting in 65 % germination compared with 4 % in the untreated control. Acid scarification (H₂SO₄ for 5 min; 31 % germination) and mechanical scarification (sandpaper for 15 min; 26 % germination) also improved germination but were less effective. Excessive heat or acid exposure damaged embryos, ultimately inhibiting germination. Potassium nitrate (KNO₃) and gibberellic acid (GA₃) treatments showed minor effects on germination, indicating that dormancy in T. purpurea is predominantly physical rather than physiological. In conclusion, hot water treatment for 6 min is recommended as a simple, safe and eco-friendly dormancy-breaking method for T. purpurea under laboratory conditions.