Effect of Variety and Type of Ratoon and Main Crops on Physical, Mechanical, and Milling Properties of Rice

The present study examined the physical properties, rupture force, and milling characteristics of the common Hashemi, Alikazemi, and Tarom rice varieties in main and ratoon crops. The experiment was conducted as a factorial(3×2) randomized complete block design with five replications. The results revealed that the thickness (1.68 mm) and sphericity of grains (0.388) were less in the main crop thanin the ratoon rice (1.71 mm and 0.398, respectively). The Hashemi variety recorded the greatest length (7.58 mm). Alikazemi recorded the greatest width (2.03 mm), thickness (1.80 mm), geometric mean diameter (3.00 mm), sphericity (0.408), surface area (25.40 mm2), bulk density (561.54kgm-3), true density (1292.24 kgm-3), and thousand grain mass (26.96 g). The highest bending rupture force(24.68 N) and head rice yield (81.36%) was obtained for the ratoon rice crop of the Hashemi variety and the lowest corresponding values (19.6 N and73.41%, respectively) were recorded for the main rice crop of the Alikazemi variety (P<0.01). There was no significant difference in compressive grain rupture force between varieties or between the main and ratoon crops.