Effect of Seed Pre-sowing Treatment on Germination of Three Acacia Species Indigenous to Botswana

Effectiveness of selected immersion-based seed pre-sowing treatments (cold water, hot water and concentrated sulphuric acid) on the germination of three Acacia species (A. tortilis, A. erioloba, and A. nigrescens) was studied between December 2012 and January 2013. For each species, four treatments (including the control) were replicated four times in a Completely Randomized Design. Percentage germination, germination mean time (GMT) and germination index (GRI) were calculated and the data were subjected to analysis of variance (ANOVA). Significant differences in germination were observed across the treatments. Concentrated sulphuric acid significantly (P < 0.01) increased the germination percentages of A. erioloba (87%) and A. nigrescens (30%) while the control, cold water and hot water treatments significantly (P < 0.01) reduced their germination percentages (5%). However, treating A. tortilis with hot water for 9 min significantly (P < 0.01) enhanced its germination percentage (30%) compared to the other treatments. As expected the control had the highest GMT, although this was not significant for A. tortilis. The GRI revealed similar trend as germination percentages across the treatments for the three Acacia species. Based on these results, we recommend concentrated sulphuric acid and hot water as suitable seed pre-treatments for enhancing the germination of the three Acacia species.