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Advisor(s)
Abstract(s)
Plants on oceanic islands often originate from
self-compatible (SC) colonizers capable of seed set by self fertilization. This fact is supported by empirical studies,
and is rooted in the hypothesis that one (or few) individuals
could find a sexual population, whereas two or more would
be required if the colonizers were self-incompatible (SI).
However, a SC colonizer would have lower heterozygosity
than SI colonizers, which could limit radiation and diver sification of lineages following establishment. Limited
evidence suggests that several species-rich island lineages
in the family Asteraceae originated from SI colonizers with
some ‘‘leakiness’’ (pseudo-self-compatibility, PSC) such
that some self-seed could be produced. This study of Tolpis
(Asteraceae) in Macaronesia provides first reports of the
breeding system in species from the Azores and Madeira,
and additional insights into variation in Canary Islands.
Tolpis from the Azores and Madeira are predominately SI
but with PSC. This study suggests that the breeding sys tems of the ancestors were either PSC, possibly from a
single colonizer, or from SI colonizers by multiple dis seminules either from a single or multiple dispersals. Long distance colonists capable of PSC combine the advantages
of reproductive assurance (via selfing) in the establishment
of sexual populations from even a single colonizer with the
higher heterozygosity resulting from its origin from an
outcrossed source population. Evolution of Tolpis on the
Canaries and Madeira has generated diversity in breeding
systems, including the origin of SC. Macaronesian Tolpis is
an excellent system for studying breeding system evolution
in a small, diverse lineage.
Description
Keywords
Island colonization/radiation Breeding system Baker’s Rule Tolpis Asteraceae Macaronesian archipelagoes . Faculdade de Ciências da Vida
Citation
Crawford, D. J., Anderson, G. J., Silva, L. B., Sequeira, M. M., Moura, M., Santos-Guerra, A., ... & Mort, M. E. (2015). Breeding systems in Tolpis (Asteraceae) in the Macaronesian islands: the Azores, Madeira and the Canaries. Plant Systematics and Evolution, 301(8), 1981-1993. https://doi.org/10.1007/s00606-015-1210-5
Publisher
Springer