The objective of including the X-ray test in Rules for Seed
Testing (Brasil, 1992) was to complement information provided
by the germination test. Before the germination test
seeds may be previously exposed to X-rays and classified as
well formed, empty or damaged. The exposition period, together
with a fixed miliamperage of the X-ray unit, regulates
the dose of X-rays that determine the radiograph density and
the degree of contrast and image quality. In this way, different
voltage/exposition periods have been adopted in seed
radiography according to the plant species, X-ray equipment,
and sensitivity of the available radiographic film (Simak,
1980).