The effects of a FLOWERING LOCUS T polymorphism on phenology, reproductive isolation and hurricane survival in the silverleaf sunflower
department or school: Science, Faculty of
department or school: Botany, Department of
data provider: DSpace
degree campus: UBCV
creator: Pascual Robles, Mariana Alicia
issued: 2023-07-26T22:01:05Z
issued: 2023
related degree: Doctor of Philosophy - PhD
degree grantor: University of British Columbia
description: Speciation is the process by which barriers to gene flow evolve between previous interbreeding populations. In this dissertation, I explore the earliest stages of speciation process, using the silverleaf sunflower (Helianthus argophyllus) as an experimental system. The species occurs on the coastal plain of southern Texas and is comprised of two ecotypes that differ in flowering time due to a presence/absence polymorphism for a major flowering time gene, FLOWERING LOCUS T (HaFT1). Asynchrony in flowering time can facilitate divergence and speciation. Therefore, I mapped the distribution of the HaFT1 polymorphism and explored its the effects on phenology and other traits. I found that HaFT1 was rare on the mainland, but both haplotypes were abundant in the barrier islands. The polymorphism at HaFT1 was closely correlated with variation in flowering time, plant height, seed size, and habitat. The rarity of HaFT1 is most likely due to high rates of immigration of the late flowering ecotype to the islands, combined with anthropogenic disturbance, which may ease establishment. I also asked if differences in flowering phenology cause assortative mating, thereby reducing gene flow and increasing reproductive isolation (RI). Parentage analyses revealed that RI was strong early and late in the flowering season when only one of the ecotypes was flowering, but weak during the middle of the season, when both ecotypes were flowering. A genomic scan based on re-sequencing data further revealed that even in the face of high gene flow in the present, assortative mating has had a genomic-wide impact, particularly in a region of low recombination where HaFT1 is found. Lastly, I took advantage of Hurricane Harvey, which hit my H. argophyllus sites, to ask what factors might aid survival of an extreme flooding event. I found that individuals that were shorter were more likely to survive. In the year following Hurricane Harvey, I observed massive establishment of H. argophyllus at sites…
aggregated CHO: https://circle.library.ubc.ca/rest/handle/2429/85322
note: THE EFFECTS OF A FLOWERING LOCUS T POLYMORPHISM ON PHENOLOGY, REPRODUCTIVE ISOLATION AND HURRICANE SURVIVAL IN THE SILVERLEAF SUNFLOWER by Mariana Alicia Pascual Robles H.B.Sc., Universidad Autónoma del Estad de Morelos, 2014 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY in THE FACULTY OF GRADUATE AND POSTDOCTORAL STUDIES (Botany) THE UNIVERSITY OF BRITISH COLUMBIA (Vancouver) July 2023 © Mariana Alicia Pascual Robles, 2023 ii The following individuals certify that they have read, and recommend to the Faculty of Graduate and Postdoctoral Studies for acceptance, the dissertation entitled: The effects of a FLOWERING LOCUS T polymorphism on phenology, reproductive isolation and hurricane survival in the silverleaf sunflower submitted by Mariana Alicia Pascual Robles in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Botany Examining Committee: Loren H. Rieseberg, Professor, Botany, UBC Supervisor Quentin Cronk, Professor, Botany, UBC Supervisory Committee Member Sean Graham, Professor, Botany, UBC Supervisory Committee Member Jeannette Whitton, Associate Professor, Botany, UBC University Examiner Sally Aitken, Professor, Forest and Conservation Sciences, UBC University Examiner iii Abstract Speciation is the process by which barriers to gene flow evolve between previous interbreeding populations. In this dissertation, I explore the earliest stages of speciation process, using the silverleaf sunflower (Helianthus argophyllus) as an experimental system. The species occurs on the coastal plain of southern Texas and is composed of two ecotypes that differ in flowering time due to a presence/absence polymorphism for a major flowering time gene, Flowering Locus T (HaFT1). Asynchrony in flowering time can facilitate divergence and speciation. Therefore, I mapped the distribution of the HaFT1 polymorphism and explored its effects on phenology and other traits. I found that HaFT1 was rare on…
has type: Thesis/Dissertation
date issued: 2023-11
is shown at: 10.14288/1.0434295
language: eng
degree discipline: Botany
provider: Vancouver : University of British Columbia Library
publisher: University of British Columbia
rights: Attribution-NonCommercial-NoDerivatives 4.0 International
rights URI: http://creativecommons.org/licenses/by-nc-nd/4.0/
scholar level: Graduate
contributor: Rieseberg, Loren H.
type: Text
identifier URI: http://hdl.handle.net/2429/85322