INFLUENCE OF SEED WEIGHT VARIATION ON SEEDLING EMERGENCE AND GROWTH OF Acacia nilotica

Acacia nilotica Willd. ex Delile is a multipurpose tree species of central importance in the social and economy throughout the warm and tropical regions of the world. A study was conducted to evaluate the influence of seed weight variation on seedling emergence and growth of Acacia nilotica. Seeds were categorized into four groups in regard to their weight, large (≥0.20g), medium (0.11-0.19g), small (≤0.10g) and a mixture of large, medium and small (acted as a control). The results showed that there were no significant (P>.05) differences among seed weight categories on germination percentage and germination speed index (GSI), although large seeds had the highest germination percentage and GSI of 90.3% and 10.0 seeds per day respectively. However, there were significant (P<.001) differences in seedling growth parameters and survival percentage among seed weight categories, with large seeds having the highest seedling growth parameters and survival percentage. This was due to differences in the food reserves. The differences on seedling growth parameters between large and medium, large and small, large and control seeds ranged from 22% to 32%, 60% to 89%, and 27% to 37% respectively. There were no significant (P>.05) differences between small seeds and control on survival percentage, even though control had a slightly higher survival percentage (48.6%) than small seeds (41.2%). There was a strong positive significant (P=.05) relationship (r>.88) between seed weight and seedling growth parameters and survival percentage. Therefore, it is recommended to use large sized seeds to get higher and quicker early seedling growth of Acacia nilotica in the nursery.