Abstract: Allopolyploidization usually causes prominent genomic and transcriptional changes, and consequently, promotes the occurrence of phenotypic modifications and/or novelties. The tetraploid Achillea alpina L. species complex in the daisy family has been clearly studied concerning genetic variations and parentage. Population genetic data point to their progenitors as the diploid A. acuminata (Ledeb.) Sch. Bip. and A. asiatica Serg., and show that they have kept two distinct parental genomes relatively intact. Phenotypically, this complex displays a range of leaf form variation between the parental species. To better understand the source of variation at the transcriptional level of the allotetraploid species, we undertook morphological and gene expression analyses with regard to leaf dissection patterns. Morphometrics of leaf traits were carried out on two members of the tetraploid complex, A. alpina and A. wilsoniana Heimerl ex Hand.‐Mazz. and their diploid progenitor species, A. acuminata and A. asiatica. In parallel, the expression patterns of a dozen leaf dissection‐related genes were detected using reverse transcription real‐time quantitative polymerase chain reaction (RT‐qPCR) method. In the allotetraploid species, important leaf dissection‐related genes, such as NAM and PIN, were expressed at the intermediate level between the two diploid species. In general, most of the genes examined in the allotetraploids were expressed at mid‐parent levels or close to one of the parental species. Considering the relative contribution of parental homeologs to the allotetraploids, there is no consistent pattern among the genes analyzed. Overall, lack of transgressive expression of leaf dissection‐related genes could be correlated with the intermediate leaf phenotypes of the allotetraploids A. alpina and A. wilsoniana between their parental species.

Key words: Achillea L., allopolyploid, gene expression, leaf marginal architecture, morphometrics