Unilateral Cross-Incompatibility in Eucalyptus: the Case of Hybridisation Between E. globulus and E. nitens

Gore, PL; Potts, Brad M.; Volker, PW; Megalos, J

doi:10.1071/bt9900383

Cited by 80 publications

(69 citation statements)

References 26 publications

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“…We discuss below the mechanisms given as potential explanation for the observed pattern and based on the fact, that the size determines the competitive ability of the pollen (Gore et al 1990;Lord and Eckard 1984;Manicacci and Barrett 1995;Vanbreukelen 1982). Pollen grain competition is expected to be strong when numerous pollen grains are competing to be the parents of only few seeds.…”

Section: Discussionmentioning

confidence: 99%

“…The size of pollen also determines the quality of the sired progeny because early fertilized ovules are more generously provisioned by the maternal plant than those that are fertilized later (Delph et al 1998). Most importantly, large pollen grains have higher chances of success in competition and successful fertilization because their size determines the growth rate of pollen tubes (Gore et al 1990;Lord and Eckard 1984;Manicacci and Barrett 1995;Vanbreukelen 1982). The relationship corresponds well to the positive trend between pollen size and stigma depth, which is a good measure of the distance that pollen tubes must grow using endogenous resources (Cruden 2009) or between pollen protein content and stigma-ovule distance (Roulston et al 2000).…”

Section: Introductionmentioning

confidence: 99%

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Large pollen at high temperature: an adaptation to increased competition on the stigma?

Ejsmond

Banasiak

et al. 2015

Plant Ecol

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Pollen availability is a major constraint of plant reproductive success. Because pollen size tradesoff with the quantity of produced grains, the link between climate characteristics and the determination of pollen size is of fundamental importance. To minimize the rate of water loss due to desiccation, a plant should produce larger grains that also have a lower surface-to-volume ratio. We used a comparative analysis to examine the hypothesis predicting increase in pollen size as a response to desiccation intensity. To test the hypothesis, we correlated the data on pollen size with the climate characteristics, temperature and desiccation intensity of the flowering period, for 232 plant species of 11 taxonomic groups. The analysis showed a positive relationship between the pollen size and temperature, but not with the desiccation intensity. We discuss the potential mechanisms by which increased temperature is an indicator of high competition among pollen grains on the stigma, which in turn is expected to promote large pollen. Our work provides insight into the temperature dependence of pollen production in plants and reveals a link between environmental temperature and the intensity of limitation of plant reproductive success by pollen availability. The result is relevant in the context of global 123Plant Ecol (2015) 216:1407-1417 DOI 10.1007/s11258-015-0519-z climate change. We also discuss why environmental temperature has to be controlled in studies dealing with pollen production, particularly in investigations of size-number trade-off.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Large pollen at high temperature: an adaptation to increased competition on the stigma?

Ejsmond

Banasiak

et al. 2015

Plant Ecol

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“…These studies have generally been undertaken to learn what barriers exist so that they can be overcome and the desired crosses can be performed (e.g. Sanyal, 1958 ;Gore et al, 1990 ;Beharav & Cohen, 1995 ;Marcella! n & Camadro, 1996).…”

Section: Prezygotic Barriersmentioning

confidence: 99%

Plant hybridization

1998

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Summary 599 I. Introduction 599 II. Concepts and terminology 600 III. Historical background 600 IV. Studies of experimental hybrids 601 1. Isolating mechanisms 601 2. Prezygotic barriers 602 (a) Gametic barriers to hybridization 602 3. Postzygotic barriers 603 (a) Chromosomal rearrangements 604 (b) Genic sterility or inviability 604 4. Hybrid vigour 605 5. Introgression 606 6. Hybrid speciation 607 V. Experimental manipulations of natural hybrid populations 609 1. Hybrid‐zone formation 610 2. Pollinator‐mediated selection 610 3. Habitat selection 612 VI. The biology of different classes of hybrids 612 1. Character expression 613 (a) Morphological characters 613 (b) Chemical characters 613 (c) Molecular characters 613 2. The fitness of different classes of hybrids 614 (a) The importance of variance 614 (b) Estimating hybrid fitness 615 3. Interactions with parasites and herbivores 616 4. Patterns of mating 617 (a) Outcrossing rate 617 (b) Hybridization frequency 618 (c) Mate choice 618 VII. Conclusions and future research 619 Acknowledgements 620 References 620 Most studies of plant hybridization are concerned with documenting its occurrence in different plant groups. Although these descriptive, historical studies are important, the majority of recent advances in our understanding of the process of hybridization are derived from a growing body of experimental microevolutionary studies. Analyses of artificially synthesized hybrids in the laboratory or glasshouse have demonstrated the importance of gametic selection as a prezygotic isolating barrier; the complex genetic basis of hybrid sterility, inviability and breakdown; and the critical role of fertility selection in hybrid speciation. Experimental manipulations of natural hybrid zones have provided critical information that cannot be obtained in the glasshouse, such as the evolutionary conditions under which hybrid zones are formed and the effects of habitat and pollinator‐mediated selection on hybrid‐zone structure and dynamics. Experimental studies also have contributed to a better understanding of the biology of different classes of hybrids. Analyses of morphological character expression, for example, have revealed transgressive segregation in the majority of later‐generation hybrids. Other studies have documented a high degree of variability in fitness among different hybrid genotypes and the rapid response of such fitness to selection – evidence that hybridization need not be an evolutionary dead end. However, a full accounting of the role of hybridization in adaptive evolution and speciation will probably require the integration of experimental and historical approaches.

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“…The larger flowers of globulus may also be a mechanism to avoid pollen swamping from smaller flowered species when invading new habitats (i.e., reproductive character displacement; Howard 1993). Subspecies globulus cannot act as the maternal parent in crosses with smaller flowered species, as the pollen tubes of smaller flowered species cannot grow down the full length of the globulus style (Gore et al 1990). …”

Section: Genetic Relationships Between the Subspecies Coresmentioning

confidence: 99%

Microsatellite and morphological analysis ofEucalyptus globuluspopulations

Jones¹,

Steane²,

Potts³

et al. 2002

Can. J. For. Res.

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Eucalyptus globulus Labill. is native to southeastern Australia and is the most important temperate hardwood plantation species in the world. It consists of four subspecies that are morphologically and geographically distinct but that are linked by morphologically and geographically intermediate populations. The Jeeralang provenance, an intermediate population from southeastern Victoria, is an important source of seed for plantations and genetic material for breeding programs because of its superior growth and wood density. To determine the genetic affinities of this provenance, 154 trees from three subspecies and the Jeeralang provenance were sampled. Analysis of 12 morphological characters verified that the Jeeralang provenance is intermediate between subspecies bicostata (Maiden, Blakely, & J. Simm.) Kirkpatr., globulus and pseudoglobulus (Naudin ex Maiden) Kirkpatr., with individuals having closest affinities to either ssp. globulus or ssp. bicostata. However, eight microsatellite loci showed that the Jeeralang provenance has greater affinities to Victorian ssp. globulus to which it is geographically closest. In contrast, Tasmanian and Victorian ssp. globulus are morphologically similar yet appear to be distinct at the molecular level. This study emphasizes the importance of using traits that are unlikely to be influenced by selection when determining the origin and affinities of populations.Résumé : Eucalyptus globulus Labill. est une espèce indigène du sud-est de l'Australie. C'est la plus importante espèce feuillue en plantation au monde. L'espèce est constituée de quatre sous-espèces qui sont morphologiquement et géographiquement distinctes. Cependant, ces sous-espèces sont liées entre elles par des populations morphologiquement et géographiquement intermédiaires. La provenance Jeeralang, une population intermédiaire de la région sud-est de Victoria, représente une source importante de semences pour l'établissement de plantations, en plus de fournir du maté-riel génétique pour les programmes d'amélioration, en raison de sa supériorité pour la croissance et la densité du bois. Afin de déterminer les affinités génétiques de cette provenance, 154 arbres représentatifs de trois sous-espèces et de la provenance Jeeralang ont été échantillonnés. La caractérisation de 12 caractères morphologiques a permis de confirmer que la provenance Jeeralang était intermédiaire entre sous-espèces bicostata (Maiden, Blakely & J. Simm.) Kirkpatr., globulus et pseudoglobulus (Naudin ex Maiden) Kirkpatr. Les individus de cette provenance avaient plus d'affinités avec ssp. globulus et ssp. bicostata. Cependant, l'analyse de huit loci de microsatellites a révélé que la provenance Jeeralang avait le plus d'affinités avec la sous-espèce globulus de la région de Victoria, dont elle est géographiquement la plus rapprochée. À l'opposé, les individus de la sous-espèce globulus des régions de Tasmanie et de Victoria étaient morphologiquement similaires même s'ils étaient distincts à l'échelle moléculaire. Cette étude souligne ...

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Unilateral Cross-Incompatibility in Eucalyptus: the Case of Hybridisation Between E. globulus and E. nitens

Cited by 80 publications

References 26 publications

Large pollen at high temperature: an adaptation to increased competition on the stigma?

Large pollen at high temperature: an adaptation to increased competition on the stigma?

Plant hybridization

Microsatellite and morphological analysis ofEucalyptus globuluspopulations

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