TY  - JOUR
A1  - Hornych, Ondrej
A1  - Ekrt, Libor
A1  - Riedel, Felix
A1  - Koutecky, Petr
A1  - Košnar, Jiří
T1  - Asymmetric hybridization in Central European populations of the Dryopteris carthusiana group
JF  - America Journal of Botany
N2  - Premise Hybridization is a key process in plant speciation. Despite its importance, there is no detailed study of hybridization rates in fern populations. A proper estimate of hybridization rates is needed to understand factors regulating hybridization. Methods We studied hybridization in the European Dryopteris carthusiana group, represented by one diploid and two tetraploid species and their hybrids. We sampled 100 individuals per population in 40 mixed populations of the D. carthusiana group across Europe. All plants were identified by measuring genome size (DAPI staining) using flow cytometry. To determine the maternal parentage of hybrids, we sequenced the chloroplast region trnL-trnF of all taxa involved. Results We found hybrids in 85% of populations. Triploid D. xambroseae occurred in every population that included both parent species and is most abundant when the parent species are equally abundant. By contrast, tetraploid D. xdeweveri was rare (15 individuals total) and triploid D. xsarvelae was absent. The parentage of hybrid taxa is asymmetric. Despite expectations from previous studies, tetraploid D. dilatata is the predominant male parent of its triploid hybrid. Conclusions This is a thorough investigation of hybridization rates in natural populations of ferns. Hybridization rates differ greatly even among closely related fern taxa. In contrast to angiosperms, our data suggest that hybridization rates are highest in balanced parent populations and support the notion that some ferns possess very weak barriers to hybridization. Our results from sequencing cpDNA challenge established notions about the correlation of ploidy level and mating tendencies.
KW  - antheridiogens
KW  - Dryopteridaceae
KW  - ferns
KW  - flow cytometry
KW  - hybridization rate
KW  - interspecific hybridization
KW  - polyploidy
KW  - reproductive isolation
KW  - speciation
KW  - trnL-trnF
Y1  - 2019
U6  - https://doi.org/10.1002/ajb2.1369
SN  - 0002-9122
SN  - 1537-2197
VL  - 106
IS  - 11
SP  - 1477
EP  - 1486
PB  - Wiley
CY  - Hoboken
ER  -