Physical and Mechanical Attributes of Five Potato Varieties

In this study, physical attributes of five common potato varieties, Marfona, Agria, Kosima, Granola and Maradona grown in Charmahal and Bakhtiary province, were determined. The physical attributes were mass, volume, physical dimensions, geometric mean diameter, specific weight, sphericity and surface area. Results showed that Marfona has higher weight, geometric mean diameter, volume and surface area, so it is good for export. Standard deviation of specific weight of Marfona was small, indicating that it is more uniform. The aforementioned variables were obtained from individual varieties of potato as well as a mixture of these varieties. The geometric shape of the varieties was ellipsoidal. Correlation coefficient and coefficient of determination of mass with diameters, volume and mass with geometric mean, mass with volume and also mass and volume with surface area was high (more than 0.9). So the relationships among these physical attributes were determined with the regression analysis. To determine mechanical properties of Marfona, Agria and Kosima tubers, triaxial and uniaxial test was selected to derive deformation energy and tangent initial modulus of elasticity. Two way t-test showed that only tangent initial modulus of elasticity of Agria was significantly different than Kosima in the same strain (20% of initial) at various lateral stresses. Therefore, we can conclude that Agria tubers are stiffer than Kosima.