Contributions to the cytogenetics of Emilia Cass. II. Induction of genomic imbalance

Artificial autotetraploids were obtained from Emilia sonchifolia and E. coccinea. Self-compatibility tests gave results concordant with previous ones on corresponding diploids but crossability of the two species with E. praetermissa was enhanced after polyploidisation. Cytological behaviour and expression of morphological traits in crosses of the autotetraploids with E. praetermissa showed that regularity of meiosis and manifestation of phenotypic traits depend on a delicate genomic balance. A method is proposed for mapping dominant traits using chromosome loss in the genomically unbalanced hybrids.