Abstract Detail

Pteridological Section/AFS

Testo, Weston [1], Barrington, David [2].

Exploring patterns of gender-biased hybridization in the North American wood ferns: insights from gametophyte breeding systems.

Interspecific hybridization is an important evolutionary mechanism in plants, especially in ferns, which are thought to possess less complex isolation mechanisms than angiosperms. Numerous studies have demonstrated differences in the strength of isolation mechanisms between reciprocal crosses of hybridizing species, resulting in biases in gametic contribution of each parental species. Gender-biased hybridization has been found to have important evolutionary implications in angiosperms; however, the phenomenon remains poorly understood in ferns. The eastern North American woodfern complex presents an excellent system in which to assess the natural occurrence of gender bias and the extent to which it is determined by gametophyte reproductive biology. In eastern North America, the diploid Dryopteris intermedia and the allotetraploids Dryopteris carthusiana and Dryopteris cristata have broadly sympatric ranges, and steile triploid hybrids between D. intermedia and each of the tetraploid species are frequently formed.  We used sequence data from the chloroplast intergenic spacer trnL-F to infer gender bias present in four populations of both hybrids in the complex. In the cases of both hybrids (D. x triploidea and D. x boottii), a strong bias in the direction of the hybridization was observed. Gametophyte ecology and reproductive biology of the parental species were studied to develop a comprehensive understanding of the influence of different gametophyte breeding systems on the outcome of hybridization events. We find that aspects of the parental species' reproductive biology, including selfing potential and antheridiogen production and response, likely influence patterns of hybridization in this group. This work is the most comprehensive study on gender-biased hybridization in ferns and highlights the relevance of gametophyte biology to evolutionary patterns and processes in ferns. 

1 - University of Vermont, Department of Plant Biology, 63 Carrigan Drive, 101 Jeffords Hall, Burlington, VT, 05405, USA
2 - University Of Vermont, Jeffords Hall, 63 Carrigan Drive, Burlington, VT, 05405, USA

Keywords:
ferns
hybridization 
antheridiogen
Dryopteris.

Presentation Type: Oral Paper:Papers for Sections
Session: 7
Location: Pines North/Boise Centre
Date: Monday, July 28th, 2014
Time: 10:45 AM
Number: 7009
Abstract ID:86
Candidate for Awards:None