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Titolo:
Pollination, breeding system, and genetic structure in two sympatric Delphinium (Ranunculaceae) species
Autore:
Williams, CF; Ruvinsky, J; Scott, PE; Hews, DK;
Indirizzi:
Idaho State Univ, Dept Biol Sci, Pocatello, ID 83209 USA Idaho State UnivPocatello ID USA 83209 Biol Sci, Pocatello, ID 83209 USA Stanford Univ, Dept Biol Sci, Stanford, CA 94305 USA Stanford Univ Stanford CA USA 94305 Dept Biol Sci, Stanford, CA 94305 USA Indiana State Univ, Dept Life Sci, Terre Haute, IN 47809 USA Indiana StateUniv Terre Haute IN USA 47809 ci, Terre Haute, IN 47809 USA Rocky Mt Biol Labs, Crested Butte, CO 81224 USA Rocky Mt Biol Labs Crested Butte CO USA 81224 Crested Butte, CO 81224 USA
Titolo Testata:
AMERICAN JOURNAL OF BOTANY
fascicolo: 9, volume: 88, anno: 2001,
pagine: 1623 - 1633
SICI:
0002-9122(200109)88:9<1623:PBSAGS>2.0.ZU;2-S
Fonte:
ISI
Lingua:
ENG
Soggetto:
MATING SYSTEM; INBREEDING DEPRESSION; POPULATION-STRUCTURE; PLANT-POPULATIONS; OUTCROSSING RATE; DIVERSITY; HISTORY; VARIABILITY; NELSONII; ISLAND;
Keywords:
breeding system; comparative study; floral display size; F statistics; geitonogamy; genetic structure; outcrossing rate; pollinator behavior;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Agriculture,Biology & Environmental Sciences
Citazioni:
64
Recensione:
Indirizzi per estratti:
Indirizzo: Williams, CF Idaho State Univ, Dept Biol Sci, Pocatello, ID 83209 USA Idaho State Univ Pocatello ID USA 83209 atello, ID 83209 USA
Citazione:
C.F. Williams et al., "Pollination, breeding system, and genetic structure in two sympatric Delphinium (Ranunculaceae) species", AM J BOTANY, 88(9), 2001, pp. 1623-1633

Abstract

Two sympatric Delphinium species, D. barbeyi and D. nuttallianum, are ecologically and morphologically similar. However, D. barbeyi has multiple, large inflorescences while D. nuttallianum has a single, small inflorescence. These differences in floral display should result in greater intraplant pollen transfer in D. barbeyi, leading to higher rates of self-pollination through geitonogamy. Reduced gene flow by pollen should in turn produce greater population differentiation among populations of D. barbeyi relative to D.nuttallianum. We tested these predictions by comparing pollinator behavior, breeding systems, outcrossing rates, and population genetic structure of sympatric populations of the two species in Colorado. Bumble bee and hummingbird pollinators visit more flowers and inflorescences per foraging bout in D. barbeyi than in D. nuttallianum. The species differed in breeding system; D. barbeyi produced more seeds by autogamy (9 vs. 2%) than D. nuttallianum and suffered no reduction in seed set in hand-self vs. outcross pollinations, in contrast to a 41% decline in D. nuttallianum. The outcrossing rate in one D. barbeyi population was 55%, but ranged from 87 to 97% in four D. nuttallianum populations. Genetic differentiation among population subdivisions estimated by hierarchical F statistics was > 10 times greater in D. barbeyi (<(<theta>)over cap> = 0.055-0.126) than D. nuttallianum (<(<theta>)over cap> = 0.004-0.009) at spatial scales ranging from metres to 3.5 km. Spatial autocorrelation analysis also indicated more pronounced local genetic structure in D. barbeyi than D. nuttallianum populations. Fixation indices (F-IS) of D. barbeyi adults were much lower than expected based on mating system equilibrium and suggest that differences in the degree of self-compatibility and/or the timing of postpollination selection/inbreeding depression between the two species further contribute to the genetic differences between them.

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Documento generato il 05/12/20 alle ore 19:34:14