Abstract Detail

Systematics Section/ASPT

Crawford, Daniel [1], Menezes de Sequeira, Miguel [2], Mort, Mark [3], Moura, Mónica [4], Santos-Guerra, Arnoldo [5], Borges Silva, Lurdes [4].

Breeding Systems and Hybrid Fertility in Tolpis (Asteraceae) in the Macaronesian Archipelagos: Comparisons of Lineages in the Canaries, Azores, and Madeira.

Two common attributes of oceanic island plant lineages are self-compatibility (SC) and the ability of morphologically-ecologically diverse species to produce vigorous, fertile hybrids. However, accumulating data, particularly from Asteraceae, demonstrate notable exceptions to these two characteristic features. Diversity in Tolpis is centered in the Macaronesian archipelagos of the Canaries, Madeira, Azores, and Cape Verde. A molecular phylogeny resolves Canary and Cape Verde taxa in a clade. Elements from Madeira and the Azores are each monophyletic but their relationships to each other and to other clades are unresolved. In Canary Island Tolpis, most species are self-incompatible (SI), with various levels of pseudo-self-compatibility (PSC) common; true SC has evolved in one species. Strong post-pollination mechanisms occur among some populations within and among species in the Canarian lineage. Compared to the Canaries, diversification of Tolpis has been limited in the Azores and Madeira, with two native species in each of the archipelagos, one endemic to each and one endemic to the two archipelagos. However, there is evidence of cryptic diversity in all three species, with recognition of additional taxa likely justified. Preliminary greenhouse studies indicate that, unlike the Canaries, strict SI is the rule for native Tolpis in the Azores and Madeira. Unlike the Canaries, true SC and the floral “selfing syndrome” have not evolved in these two archipelagos. Plants from any one archipelago are cross-compatible with elements from the other two island systems, with vigorous, morphologically intermediate F₁ plants produced. However, pollen fertility is very low (mostly below 10%) in hybrids between Canarian plants and either Azorean or Madeiran species. Crosses between plants from the Azores and Madeira exhibit higher F₁ pollen fertilities that range from 25-75%. Hybrid fertilities between plants of Tolpis succulenta from Madeira and the Azores are lower (35-50%) than those between plants of this species from the same archipelago (65-80%), though sampling has been limited. These data are concordant with morphological and molecular phylogenetic data indicating that plants referable to T. succulenta on the two archipelagos should be recognized as distinct species. Like the Canaries, there is evidence of post-pollination factors reducing hybrid fertility, both among populations of the same species, and between species in both the Azores and Madeira. The nature and implications of breeding systems and post-pollination sterility factors for the diversification of Tolpis in these archipelagos will be discussed.

Broader Impacts:

1 - University of Kansas, Department of Ecology And Evolutionary Biology, 1200 Sunnyside Avenue, Haworth Hall, Lawrence, KS, 66045-7534, USA
2 - Universidade da Madeira, Centro de Ciências da Vida, Campus da Penteada, Funchal, Portugal
3 - University of Kansas, 1200 Sunnyside Avenue, Lawrence, KS, 66045, USA
4 - Universidade dos Açores , Departamento de Biologia, Rua da Mãe de Deus, Ponta Delgada, Azores, Portugal
5 - Unidad de Botánica Aplicada (ICIA) , Jardín de Aclimatación de La Orotava, Retama, No. 2, Puerto de la Cruz, Canary Islands, Spain

Keywords:
Tolpis,
breeding system
hybrid fertility
Macaronesian islands.

Presentation Type: Oral Paper:Papers for Sections
Session: 35
Location: Versailles Ballroom/Riverside Hilton
Date: Tuesday, July 30th, 2013
Time: 5:00 PM
Number: 35014
Abstract ID:409
Candidate for Awards:None