Abstract

Determining pre-sowing treatments at the seedling stage is critical to effectively managing seed germination and growth. This study investigated the effects of pre-sowing treatments on Grevillea seed germination and early seedling growth. Grevillea robusta seed germination and seedling growth performance under different water soaking treatments were evaluated for three months under nursery and laboratory conditions. A total of 250 seeds were pre-treated with cold water and soaked for 12, 24, 36, 48, and 72 hours, respectively, while the control was not soaked. Each treatment used a total of 25 seeds. Sow the seeds directly into polyethylene bags filled with a homogeneous growing medium (top forest soil, sand, and fertilizer) mixed in the recommended proportions to avoid disturbing the root system after germination. Seeds were sown using a randomized complete block design (RCBD), with 10 treatments and 3 replicates. The growth parameters evaluated were root collar diameter (cm), seedling height (cm), root depth (cm), survival rate (%), germination presentation, and seed germination rate. The results showed that there were significant differences (p < 0.05) in the seedling growth parameters (root collar diameter, root depth, and seedling height) of different pre-planting treatments. The findings indicated that Grevillea seeds immersed in cold water (T3) had a slightly better survival rate (92%), whereas under T9, root collar diameter (0.44 cm), seedling height (31.05 cm), and root depth (25.62 cm) all showed slightly greater growth performances. Therefore, cold water soaking (T9) is the best pre- sowing treatment when compared to other seed-enhancing pre-treatments for promoting uniform and optimal seed germination and early seedling growth. Seeds sown without any treatment (control) were found to have the poorest growth performance among all parameters studied. The present study showed that seed germination percentage, germination time, and seedling vigor were affected by the cold water soaking of seeds. This indicates that pre-sowing treatments significantly affected seed germination and seedling growth.