Incompatibility as a new method for identification of pyrethrum clones

Summary

Pyrethrum clones cannot be satisfactorily identified by morphological traits, or by contents or types of pyrethrins.

In pyrethrum a sporophytic incompatibility system operates. Most clones are strongly self-incompatible and cross-compatible. This was used as the basis of a revised identification system. It is assumed that in self-incompatibility and cross-compatibility the clones are identical. To test this assumption 128 different genotypes were selfed and crossed in 86 combinations. Only two genotypes (1.6%) were self-compatible and only one cross (1.2%) was reciprocally cross-incompatible.

Since only a restricted number of clones is recommended and therefore issued, the incompatibility test together with morphology, especially of the flower, ensures an entirely satisfactory identification. Two applications are given.