Effects of Different Pretreatments to the Seed on Seedling Emergence and Growth of Acacia polyacantha

Abstract

Acacia polyacantha Willd. is a multipurpose tree species prioritised as one of the agroforestry tree species in Malawi. However, its use in agroforestry practices is limited by the low seedling growth and survival at the nursery stage. A study was conducted to evaluate the seedling growth and survival of Acacia polyacantha as affected by different pretreatments on the seeds at Malawi College of Forestry and Wildlife nursery, Malawi. Seeds were subjected to five presowing seed treatments methods, namely, immersion in cold water at room temperature for 24 hours, immersion in hot water (100°C) for 5 minutes, immersion in concentrated sulfuric acid (0.3 M H 2 SO 4 ) for 20 minutes, scarification by mechanically nicking using secateurs, and a control where seeds were sown without any treatment. The results indicate that presowing seed treatments have positive influence on the seedling growth and survival percentage. Nicked seeds exhibited the highest significant ( P<0.001 ) performance for vegetative characteristics of height, root collar diameter, number of leaves, and survival percentage compared to other pretreatments. Therefore, it is suggested to use nicking as a pretreatment method on Acacia polyacantha seeds in order to enhance the speed and the amount of early seedling growth at the nursery stage.