CHARACTERS
What is the minimum difference between varieties that indicates "distinctness"?
The PVP Act states that a novel variety is distinct when it "clearly differs by one or more identifiable morphological, physiological, or other characteristics ... from all prior varieties of public knowledge."
The meanings of "characteristic" and "identifiable" are purposefully vague in this definition to allow for future advances in knowledge and methodology.
Morphological
Based on stable, identifiable characters
Biochemical
Typically included if there is any claim (viz., alkaloid content, secondary metabolites, aroma etc.) to be compared with existing varieties⁄ germplasm.
Molecular
DNA fingerprinting (in combination with and addition to one or more of the above)