In spite of the good aroma and flavor of cooked rice for common rice varieties in Isfahan province they have excessive breakage losses, qualitatively. So recognition and determination of physical and mechanical properties of these varieties are a matter of importance. In this study some principal physical and mechanical properties of current rice varieties in Isfahan was determined at different moisture content. Also the correlation of head rice yield (HRY) with these properties was investigated. This consideration was conducted using a randomized complete design with factorial layout that included two varieties (Sorkheh and Sazandegi) and three level of moisture content (MC) (12, 14 and 16% wet basis) as the main parameters. In determining physical properties, dimensions (major, intermediate and minor diameters, geometric mean diameter (GMD) and sphericity), weight, bulk and true density, porosity, static coefficient of friction (over the surfaces of different material) and angle of repose were sub parameters. For determination of mechanical properties two compression and three point bending tests were conducted. Some principal mechanical properties such as biological yield point, maximum rupture force and energy, apparent modulus of elasticity and toughness were determined under compression test from the force-deformation curves of rice kernels. Similarly, maximum rupture force and energy, maximum bending strength and apparent modulus of elasticity were gained under three point bending test. According to statistical analysis of data, the effect of variety type on dimensio weight, bulk density, porosity, static coefficient of friction and angle of repose was significant at 0.1% statistical level (SL). Effect of varieties on true density was not significant. Also the MC had a significant effect at 1% SL on minor diameter and weight, 0.1% SL on bulk and true density, porosity, static coefficient of friction and angle of repose and 5% SL on GMD. The GMD, sphericity, true density, static coefficient of friction and angle of repose increased and bulk density decreased as MC increased. The concrete, galvanized, wood and glass surfaces had the maximum static coefficient of friction, respectively. The statistical analysis for compression test indicated that variety type had a significant effect at 1% SL on yield point and apparent modulus of elasticity and 0.1% SL on maximum ru
