Effect of hormonal priming on Seed germination and Seedling growth of Akasia (Acacia Mangium Willd.) and Kenaf (Hibiscus Cannabinus L.)

Akasia (Acacia mangium Willd.) and kenaf (Hibiscus cannabinus L.) have great economic and environmental values. Poor germination of these crop species obstructs early and uniform seedling availability and supply. Plant growth hormones such as salicylic acid (SA), gibberellic acid (GA₃) and cytokinin (CK) are known to enhance seed germination of many crop species. Hence, hormonal priming pre-treatment of seeds was considered a viable option to solve the germination problem. This study is aimed to determine the effects of seed priming pre-treatments with different types of hormones on germination and post—emergent growth of these two crop species. In order to study the effects of hormonal priming on seed germination and seedling post-emergent growth, a factorial experiment in a completely randomized design was conducted. Seeds of A. mangium and H. cannabinus were soaked in three different concentrations (50, 100 and 150 ppm) of SA, GA₃ and CK for 5 hours. The results indicate that all the pre-treatment using hormonal priming techniques, improved the post-emergent seedling growth for these two species. No significant differences of shoot and root lengths were observed between control group and hormonal priming pre-treatments. However, the hormones affect the germination capacity of these two species. GA₃ and CK have significantly higher gennination than SA in term of total seed germination toward different species. Seeds primed with 150 ppm GA₃ and 50 ppm CK were more effective in reducing the time lag in germination and improved the seed germination percentage, energy, capacity and root and shoot length of the seedlings. The analysis of variance showed that there was a significantly interaction between species and hormone pre-treatments, but the interaction between species and concentration was not significant on the total seed gennination of A. mangium and H. cannabinus. This indicates that total seed germination depended on species and type of hormone used. The best germination was obtained by seeds of H. cannabinus primed with with GA₃ and CK.