A summary of the physical properties of Sorkheh and
Sazandegi cultivars is shown in Table 1. Rough rice grain
length and thickness values practically did not present
significant differences between the cultivars, but there were
significant differences between the cultivars at the 1% level
of probability between the widths for the studied cultivars.
The average rough rice length, width and thickness for
Sorkheh variety were found to be 8.45, 2.36, and 1.86 mm,
respectively, while 8.54, 2.47, and 1.83mm were obtained
for Sazandegi variety. Seeds graded uniformly, according
to size, provide uniform germination and usually give
increased harvesting yield. Effective grading according to
width, through sieves with round holes, occurs when the
particles lie along the axis perpendicular to the surface of
the sieve. For this, the sieve must be vibrating vertically.
When the length of the particle is no more than twice the
width, the grading is satisfactory even on sieves which
vibrate horizontally (Klenin et al., 1986). Considering the
latter fact, for grading the tested cultivars, grading based
on horizontal vibration can be performed. The equivalent
diameters for Sorkheh and Sazandegi cultivars were 3.3
and 3.4 mm, respectively. Based on statistical analysis, a
significant difference at the 5% level probability was
observed between them.