Seed Pretreatment and Germination Rates of Parkia biglobosa

Abstract

Parkia biglobosa (African locust bean) is a versatile leguminous tree with high ecological, nutritional, and economic importance in Sub-Saharan Africa. However, seed dormancy caused by a stiff seed coat limits its propagation. Aim: This study investigated the effects of several pretreatment procedures on P. biglobosa germination and early seedling growth. Location and duration: The study was conducted at Njala University's Department of Forestry and Wood Science in Southern Sierra Leone. It took a total of 8weeks to observe seed germination and field data recording. Methodology: Seeds were subjected to four treatments: physical scarification with sandpaper (T1), soaking in hot water (T2), soaking in water at room temperature (T3), and untreated control (T0). A total of 400 seeds (100 per treatment) were sown in a randomized complete block design using loamy soil and river sand in equal proportion. Over an eight-week observation period, germination rates, emergence rates (ER), and emergence rate indices (ERI) were recorded and analyzed using chi-square tests. Results: The results showed that scarified seeds (T1) had the highest germination rate (75%), followed by room-temperature-soaked seeds (T3) at 64%, the control (T0) at 50%, and hot water-treated seeds (T2) at 27%. Although T1 had the highest ER, T3 had the highest ERI (32.92), implying faster and more uniform early seedling emergence. Statistical study revealed a substantial correlation between pretreatment type and germination outcome (χ² = 51.75, p < 0.001). Conclusion: The data indicate that physical scarification and soaking in water at room temperature are effective, low-cost strategies for overcoming seed dormancy in P. biglobosa, however hot water treatment may reduce seed viability.