Optimizing seed germination in Canarium strictum Roxb., success through pretreatment at low moisture content

Canarium strictum Roxb. (Black Dammer tree), is highly valued for its aromatic resin and medicinal properties. However, its sustainability is threatened by issues like unsustainable harvesting practices, overexploitation for resin, limited seed regeneration, and low survival rates of seedlings in natural habitats. This study aims to investigate how pretreatment methods, in conjunction with varying moisture levels, can enhance the germination capacity of these seeds. Seeds initially at 20% and reduced at 12% moisture content underwent various mechanical and chemical pretreatments to enhance germination. Control sets at both moisture levels exhibited a 56.66% germination rate. Seeds at 20% moisture content showed an increased germination percentage of 73.33% after 7 days of weathering, with a mean germination time of 79.18 days. Conversely, pretreatments at reduced moisture content, including 24-hour water soaking and immersion in a 1% KNO₃ solution, achieved the highest germination rate (76.66%) with a lower mean germination time of 29.18 days. Seedlings resulting from immersion in a 1% KNO₃ solution for 24 h under reduced moisture conditions displayed enhanced vigour, evidenced by superior seedling length, collar girth, and root count compared to alternative pretreatments. Hence, the seed pretreatments optimized at reduced moisture levels significantly improves germination rates, yields high-quality seedlings, and decreases the sprouting time compared to treatments at initial moisture content levels.