means any plant grouping within a single botanical taxon of the lowest known rank, which grouping can be—
| (a) | defined by the expression of the characteristics resulting from a given genotype or combination of genotypes; |
| (b) | distinguished from any other plant grouping by the expression of at least one of the said characteristics; and |
| (c) | considered as a unit with regard to its suitability for being propagated unchanged. |