Abstract
Sapindus mukorossi (Gaertn.), commonly known as soapnut, is a valuable species within the Sapindaceae family, known for its saponin-rich fruits with extensive applications in pharmaceuticals, cosmetics, and natural detergents. However, the hard seed coat of S. mukorossi imposes significant dormancy, posing a challenge for propagation. This study evaluates the effectiveness of various pretreatment methods in breaking seed coat dormancy and enhancing germination. The pretreatments included a control (untreated seeds), 15-min hot water soak, 15 min heat at 200 °C, sulfuric acid soak for 1, 2, and 3 h, and mechanical scarification using sandpaper. Over a 30-day period, germination performance was assessed through final germination percentage (FGP), mean germination time (MGT), coefficient of velocity of germination (CVG), time to 50% germination (T50), and mean daily germination (MDG). Results showed that the 2-h sulfuric acid treatment achieved the highest FGP at 96.67%. The control group exhibited a low FGP of 7.50%, indicating high seed dormancy in untreated seeds. Heat treatment and mechanical scarification also improved FGP to 15.83% and 11.67%, respectively. No germination occurred after a hot water soak. Statistical analysis showed significant differences among the treatments for all germination traits (FGP, MGT, CVG, T50, and MDG) with p-values <0.001. This study provides valuable insights into this economically important species’ large-scale propagation and cultivation.