GERMINATION ECOLOGY OF 12 INDIGENOUS AND 8 EXOTIC MULTIPURPOSE LEGUMINOUS SPECIES FROM ETHIOPIA

The germination requirements of seeds of 20 leguminous species were st udied in three experiments. In the first experiment, seeds were subjec ted to mechanical scarification, sulphuric acid and boiling water trea tments. In the second experiment, they were treated with dry heat at 6 0, 80 and 100 degrees C. In the third experiment, seeds were placed at different temperature regimes (10, 15, 20, 25 and 30 degrees C) on a thermogradient. Sulphuric acid treatment improved germination in all t he species while mechanical scarification improved germination in 18 o ut of 20 species. Boiling water treatment improved germination in 15 s pecies but proved to be lethal to five species. Similarly, germination was significantly improved in 11 out of 16 species treated with dry h eat. Germination was faster and higher at both 25 degrees C and 30 deg rees C and the optimum temperature for germination was between 20 degr ees C and 30 degrees C for all the species. Mechanical scarification, sulphuric acid and boiling water treatments as well as dry heat were e ffective to overcome seed coat imposed dormancy in the species studied . It was not possible to recommend a treatment which is equally effect ive for all the species. However, boiling water is a practical method for achieving rapid, uniform and high germination except in five of th e species for which it proved to be lethal. In the latter case, either mechanical scarification or sulphuric acid treatment should be used. Seeds of Millettia ferruginea should be sown when they are fresh to ge t high germination as they tend to lose their viability during storage . Results from the present study show that once the dormancy in legumi nous species with hard seed coats is broken, the seeds germinate in wi de ranges of temperature.