GERMINATION OF WOODLAND MAHOGANY (<em>TRICHILIA</em> <em>EMETICA</em>) FOLLOWING MANUAL SEED COAT SCARIFICATION AND POTASSIUM NITRATE TREATMENTS

Abstract

Experiments were carried out in the laboratory and nursery to study the effect of manual seed coat scarification and soaking in potassium nitrate (KNO3) on the germination of seeds of woodland mahogany (Trichilia emetica). Seeds without treatment attained a total germination of 28 % in the laboratory and 33 % in the nursery. Seeds with complete removal of aril alone or complete removal of aril associated with partial removal of seed coat at the radicular end without soaking in KNO₃ gave 88/99 % germination in the laboratory and 77/93 % in the nursery. Trends in germination value were similar to cumulative germination percentages. Germination times were shortest (13 days) in seeds where aril removal was associated with partial removal of the seed coat and longest (31 days) in unscarified seeds. Application of KNO₃ produced a slight adverse effect of germination. The main cause of poor germination was due to the impermeability of the aril to water. It is recommended that aril alone should be completely removed before sowing seeds of T. emetica.