Effect of moisture content on physical properties of sugar beet seed

In this study, some seed physical properties of two sugar beet varieties, Shirin and Gadouk (436), were evaluated as a function of moisture content. Physical properties included length, width, thickness, arithmetic and geometric mean diameters, sphericity, thousand seed weight, angle of repose, terminal velocity, true density, bulk density, porosity, and coefficient of friction. Four moisture contents (8.4, 9.8, 11.9, and 14.0%) and two varieties were evaluated in factorial experiment based on completely randomized design. With increase in moisture content, the length, width, and thickness of Shirin seeds increased by 11.37, 15.61, 8.82%, and for Gadouk (436) variety, increased by 5, 4.54, and 6.69%, respectively. Arithmetic and geometric mean diameters, sphericity, thousand seed weight, angle of repose and terminal velocity were found to increase linearly by the increase in moisture content whilst true density, bulk density, and porosity of the seeds decreased. The friction coefficient of the seeds of both varieties increased with moisture content increase on four structural surfaces including rubber, plywood layer, galvanized steel, and aluminum. The maximum and minimum friction coefficient for the seeds of the both varieties was achieved on rubber and galvanized steel surfaces, respectively. The relationship between the physical properties and seed moisture content was obtained as regression equations, and were validated by analysis of variance. Results showed that the obtained equations can be used in prediction of the seed physical properties in other moisture content levels.