Effect of the moisture content on the physical properties of bitter gourd seed

Some physical and germination properties of bitter gourd seed were determined in a moisture content range of 9.3-32.1% d.b. For this moisture, the average length, width, and thickness of seed increased by 3.68, 4.07, and 4.56%, respectively. The geometric properties increased with increasing moisture content. The bulk density and rupture force decreased while thousand seed mass, true density, porosity, terminal velocity and static coefficient of friction increased with increasing moisture content. At all moisture contents, the maximum friction was offered by rubber, followed by plywood, aluminum, and galvanized iron surface. The seed germination duration, seedling emergence percentage, and germination index values gave the best results at the 19.9% moisture content, whereas fresh seedling mass was not affected by different moisture contents.