INFLUENCE OF PRE GERMINATION TREATMENTS ON OVERCOMING SEED DORMANCY AND SEEDLING GROWTH OF BAOBAB (Adansonia digitata L.)

Abstract

There is an urgent need to overcome seed dormancy especially in some multi-benefit tree like baobab, which can be successfully cultivated in Southern Egypt, in order to improve their regeneration. Therefore, this study was carried out to investigate the effects of some pre-germination treatments i.e., soaking in tap water, boiling water or sulphuric acid at 98.5% for either 30 or 60 min, mechanical scarification with sandpaper alone or combined with soaking in sulphuric acid 98.5% for either 30 or 60 min, on germination characters and seedling traits of Adansonia digitata L. Results revealed that all pre-germination treatments significantly increased all germination parameters, growth performance and some chemical traits compared to the untreated seeds, except for soaking seeds in tap water. The descending order of pre-sowing treatments was scratching baobab seeds then soaking in sulphuric acid 98.5% for 60 or 30 min ˃ soaking in sulphuric acid 98.5% for 60 or 30 min˃ mechanical scarification with sandpaper ˃ boiling water. In the same order was minimized number of days from sowing until the emergence of the plumule from 68 to 6 days and increasing germination (%) from 9 to 94% for untreated and soaking in tap water without significant differences in between and scratching seeds then soaking in sulphuric acid 98.5% for 60 min, respectively. There were increments in seedling height (from 4.27 to 57.58%) and in stem diameter (from 21.67 to 61.48%) for seeds soaked in tap water, and scratching seeds then soaking in sulphuric acid 98.5% for 60 min, respectively. Generally, all previous treatments except soaking in tap water led to breaking baobab seed dormancy. The best treatment was scratching seeds before soaking in sulphuric acid 98.5% for 30 mints.