Flowering and mating system in hybridizing Carpobrotus (Aizoaceae) in coastal California

1998 ◽  
Vol 76 (7) ◽  
pp. 1165-1169 ◽  
Author(s):  
Montserrat Vilà ◽  
Ewald Weber ◽  
Carla M D'Antonio
Keyword(s):  
Mating System ◽  
Exotic Species ◽  
Seed Set ◽  
High Potential ◽  
Natural Hybridization ◽  
Pesticide Application ◽  
Hybrid Fitness ◽  
Carpobrotus Edulis ◽  
Self Fertilization ◽  
Corolla Diameter

Patterns of flowering and pollination visit of Carpobrotus spp. were examined to determine the hybridization potential between the introduced succulent perennial Carpobrotus edulis and its native congener, Carpobrotus chilensis, in coastal California. Both species flower from March to July and both are visited by the same Thysanoptera and Coleoptera taxa. Flowers from hybrid-appearing individuals were intermediate in corolla diameter. Emasculation and bagging experiments suggest that C. edulis and hybrid morphotypes have facultative agamospermia, whereas C. chilensis has facultative self-fertilization. Emasculated C. chilensis did not set seeds. Pesticide application and flower bagging suggest that 80% of seed set in self-pollinated C. chilensis flowers is mediated by thrips. Our results suggest that there is high potential for natural hybridization in Carpobrotus species in California and that Carpobrotus populations can persist without cross-pollination.Key words: Carpobrotus, exotic species, facultative agamospermia, hybrid fitness, invasion, pollination preference.

scholarly journals Mating System and Hybridity in Eucalyptus pauciflora

1977 ◽  
Vol 30 (4) ◽  
pp. 337 ◽  
Author(s):  
MA Phillips ◽  
AHD Brown
Keyword(s):  
Mating System ◽  
Outcrossing Rate ◽  
Seedling Stage ◽  
Average Heterozygosity ◽  
Evolutionary Advantage ◽  
Allozyme Polymorphisms ◽  
Self Fertilization

Allozyme polymorphisms at four loci expressed in seeds, and three other loci expressed in seedlings, were used to determine the outcrossing rate in three natural subalpine populations of snow gum (E. paucijlora). Based on the seed loci data, an estimated 37 % of seed was derived from self-fertilization and 63 % from random outcrossing. In the most elevated population the estimate after germination was similar. However, at lower elevations the frequency of effective self-fertilization estimated at the seedling stage was only 16 %. The less elevated populations also showed a greater average heterozygosity and a larger increase in heterozygosity in the adult over the progeny stages. Heterosis apparently operated differentially in these populations-it was more intense at the lower altitudes. Selection in favour of outcrossed individuals may be an important factor in checking the spread through the population of genes which promote self-fertilization, and which would otherwise enjoy an evolutionary advantage.

Floral trait variation and links to climate in the mixed-mating annual Clarkia pulchella

Botany ◽  
2018 ◽  
Vol 96 (7) ◽  
pp. 425-435 ◽  
Author(s):  
Devin E. Gamble ◽  
Megan Bontrager ◽  
Amy L. Angert
Keyword(s):  
Mating System ◽  
Common Garden ◽  
Moisture Stress ◽  
Floral Traits ◽  
Mixed Mating ◽  
Floral Trait ◽  
Local Climate ◽  
Self Fertilization ◽  
Clarkia Pulchella ◽  
Watering Treatment

The benefits of self-fertilization can vary across environments, leading to selection for different reproductive strategies and influencing the evolution of floral traits. Although stressful conditions have been suggested to favour self-pollination, the role of climate as a driver of mating-system variation is generally not well understood. Here, we investigate the contributions of local climate to intraspecific differences in mating-system traits in Clarkia pulchella Pursh in a common-garden growth chamber experiment. We also tested for plastic responses to soil moisture with watering treatments. Herkogamy (anther–stigma spacing) correlated positively with dichogamy (timing of anther–stigma receptivity) and date of first flower, and northern populations had smaller petals and flowered earlier in response to experimental drought. Watering treatment alone had little effect on traits, and dichogamy unexpectedly decreased with annual precipitation. Populations also differed in phenological response to watering treatment, based on precipitation and winter temperature of their origin, indicating that populations from cool and dry sites have greater plasticity under different levels of moisture stress. While some variation in floral traits is attributable to climate, further investigation into variation in pollinator communities and the indirect effects of climate on mating system can improve our understanding of the evolution of plant mating.

scholarly journals The demography and population genomics of evolutionary transitions to self-fertilization in plants

2014 ◽  
Vol 369 (1648) ◽  
pp. 20130344 ◽  
Author(s):  
Spencer C. H. Barrett ◽  
Ramesh Arunkumar ◽  
Stephen I. Wright
Keyword(s):  
Mating System ◽  
Population Genomics ◽  
Molecular Data ◽  
Reproductive Assurance ◽  
Evolutionary Transitions ◽  
Cast Doubt ◽  
Self Fertilization ◽  
Loss Of Diversity ◽  
Linked Selection

The evolution of self-fertilization from outcrossing has occurred on numerous occasions in flowering plants. This shift in mating system profoundly influences the morphology, ecology, genetics and evolution of selfing lineages. As a result, there has been sustained interest in understanding the mechanisms driving the evolution of selfing and its environmental context. Recently, patterns of molecular variation have been used to make inferences about the selective mechanisms associated with mating system transitions. However, these inferences can be complicated by the action of linked selection following the transition. Here, using multilocus simulations and comparative molecular data from related selfers and outcrossers, we demonstrate that there is little evidence for strong bottlenecks associated with initial transitions to selfing, and our simulation results cast doubt on whether it is possible to infer the role of bottlenecks associated with reproductive assurance in the evolution of selfing. They indicate that the effects of background selection on the loss of diversity and efficacy of selection occur rapidly following the shift to high selfing. Future comparative studies that integrate explicit ecological and genomic details are necessary for quantifying the independent and joint effects of selection and demography on transitions to selfing and the loss of genetic diversity.

scholarly journals Isolation and Lack of Potential Mates may Threaten an Endangered Arid-Zone Acacia

2019 ◽  
Vol 110 (6) ◽  
pp. 738-745
Author(s):  
Cairo N Forrest ◽  
David G Roberts ◽  
Andrew J Denham ◽  
David J Ayre
Keyword(s):  
Reproductive Success ◽  
Seed Set ◽  
Arid Zone ◽  
Genotypic Diversity ◽  
Geographic Range ◽  
Landscape Scale ◽  
Reproductive Assurance ◽  
Threatened Plants ◽  
Self Fertilization ◽  
Adult Plants

Abstract Clonality may provide reproductive assurance for many threatened plants while limiting sexual reproductive success either through energetic tradeoffs or because clones are self-incompatible. Most stands of the Australian arid-zone plant Acacia carneorum, flower annually but low seed set and an absence of sexual recruitment now suggest that this species and other, important arid-zone ecosystem engineers may have low genotypic diversity. Indeed, our recent landscape-scale genetic study revealed that stands are typically monoclonal, with genets usually separated by kilometers. An inability to set sexually produced seed or a lack of genetically diverse mates may explain almost system-wide reproductive failure. Here, using microsatellite markers, we genotyped 100 seeds from a rare fruiting stand (Middle-Camp), together with all adult plants within it and its 4 neighboring stands (up to 5 km distant). As expected, all stands surveyed were monoclonal. However, the Middle-Camp seeds were generated sexually. Comparing seed genotypes with the single Middle-Camp genotype and those of genets from neighboring and other regional stands (n = 26), revealed that 73 seeds were sired by the Middle-Camp genet. Within these Middle-Camp seeds we detected 19 genotypes in proportions consistent with self-fertilization of that genet. For the remaining 27 seeds, comprising 8 different genotypes, paternity was assigned to the nearest neighboring stands Mallee and Mallee-West, approximately 1 km distant. Ironically, given this species’ vast geographic range, a small number of stands with reproductively compatible near neighbors may provide the only sources of novel genotypes.

Mating system and genetic polymorphism in populations of Secale cereale and S. vavilovii

1984 ◽  
Vol 26 (3) ◽  
pp. 308-317 ◽  
Author(s):  
M. Pérez De La Vega ◽  
R. W. Allard
Keyword(s):  
Mating System ◽  
Secale Cereale ◽  
Random Mating ◽  
Genetic Studies ◽  
Banding Patterns ◽  
Enzyme Systems ◽  
Incompatibility System ◽  
Secale Cereale L ◽  
Isozyme Polymorphism ◽  
Self Fertilization

Electrophoretic banding patterns were determined for nine enzyme systems (IPO, PGM, PGI, LAP, GOT, EST, PHOS, MDH, CPX) in four populations of Secale cereale L. from widely different geographical areas, and in one population of S. vavilovii Grossh. Secale cereale was found to be extensively variable and S. vavilovii invariant for these enzyme systems. Formal genetic studies of nine polymorphic banding zones in S. cereale revealed that each zone was under single locus control. Mating system studies based on these loci indicated that 8% of self-fertilization occurred under field conditions in a population of S. cereale, a species with a highly developed self-incompatibility system. Each population was characterized by fewer heterozygotes than expected in random mating populations. Genotypic and allelic frequencies were nearly identical in four populations of S. cereale, despite their diverse origins and different cytological characteristics.Key words: mating system, Secale, rye, isozyme polymorphism.

scholarly journals Genomic Signatures of Sexual Selection on Pollen-Expressed Genes in Arabis alpina

2021 ◽  
Author(s):  
Juanita Gutiérrez-Valencia ◽  
Marco Fracassetti ◽  
Robert Horvath ◽  
Benjamin Laenen ◽  
Aurélie Désamore ◽  
...  
Keyword(s):  
Sexual Selection ◽  
Mating System ◽  
Male Gametophyte ◽  
Embryo Sac ◽  
Purifying Selection ◽  
Pollen Competition ◽  
Molecular Signatures ◽  
Sexual Competition ◽  
Self Fertilization ◽  
Arabis Alpina

Abstract Fertilization in angiosperms involves the germination of pollen on the stigma, followed by the extrusion of a pollen tube that elongates through the style and delivers two sperm cells to the embryo sac. Sexual selection could occur throughout this process when male gametophytes compete for fertilization. The strength of sexual selection during pollen competition should be affected by the number of genotypes deposited on the stigma. As increased self-fertilization reduces the number of mating partners, and the genetic diversity and heterozygosity of populations, it should thereby reduce the intensity of sexual selection during pollen competition. Despite the prevalence of mating system shifts, few studies have directly compared the molecular signatures of sexual selection during pollen competition in populations with different mating systems. Here we analyzed whole-genome sequences from natural populations of Arabis alpina, a species showing mating system variation across its distribution, to test whether shifts from cross- to self-fertilization result in molecular signatures consistent with sexual selection on genes involved in pollen competition. We found evidence for efficient purifying selection on genes expressed in vegetative pollen, and overall weaker selection on sperm-expressed genes. This pattern was robust when controlling for gene expression level and specificity. In agreement with the expectation that sexual selection intensifies under cross-fertilization, we found that the efficacy of purifying selection on male gametophyte-expressed genes was significantly stronger in genetically more diverse and outbred populations. Our results show that intra-sexual competition shapes the evolution of pollen-expressed genes, and that its strength fades with increasing self-fertilization rates.

scholarly journals Floral biology of medicinal plants I. Apiaceae species

2000 ◽  
Vol 6 (3) ◽  
Author(s):  
É. Németh ◽  
G. Székely
Keyword(s):  
Medicinal Plants ◽  
Seed Set ◽  
Floral Biology ◽  
Coriandrum Sativum ◽  
Anethum Graveolens ◽  
Foeniculum Vulgare ◽  
Genotype Combination ◽  
Angelica Archangelica ◽  
Self Fertilization ◽  
Male Flowers

The Apiaceae family consists of several species which are well known for their therapeutical use and also as spice plants. Although fennel (Foeniculum vulgare Mill.), caraway (Carton carvi L.), anise (Pimpinella anisum L.), coriander (Coriandrum sativum L.), dill (Anethum graveolens L.), angelica (Angelica archangelica L.) and lovage (Levisticum officinale Koch.) are also economically considerable cultures, data on their flowering biology are rather scarce. This review supports data on the characteristic constitution of flowers and inflorescences, flowering dynamics, pollination mechanism and crossability of some of the most significant medicinal and spice species. The inflorescence is a compound umbel. Flowers are hermaphrodite, however also monoeceous, mainly male flowers are turning up too. In blooming of a plant individual, a strict sequence is observed. The main umbel is the first to bloom, followed by the different range umbels in order of their range. In their pollination, both wind and insects are considered to be active. For each species, proterandry is characteristic. Although autogamy is considered to be almost unpossible, and geintonogamy as well as xenogamy to be the most characteristic ways of fertilization, several cases of self-fertilization proved to be also successful. Crossability among cultivars or species is depending on the genotype combination and usually produces less seed set than the above forms of fertiliiation.

scholarly journals Limited phenological and pollinator-mediated isolation among selfing and outcrossing Arabidopsis lyrata populations

2020 ◽  
Vol 287 (1939) ◽  
pp. 20202323
Author(s):  
Courtney E. Gorman ◽  
Lindsay Bond ◽  
Mark van Kleunen ◽  
Marcel E. Dorken ◽  
Marc Stift
Keyword(s):  
Reproductive Isolation ◽  
Mating System ◽  
Common Garden ◽  
Common Garden Experiment ◽  
Pollinator Visitation ◽  
Arabidopsis Lyrata ◽  
Pollinator Preference ◽  
Pollination Mechanisms ◽  
Self Fertilization ◽  
Mechanistic Basis

Transitions from outcrossing to selfing have been a frequent evolutionary shift in plants and clearly play a role in species divergence. However, many questions remain about the initial mechanistic basis of reproductive isolation during the evolution of selfing. For instance, how important are pre-zygotic pre-pollination mechanisms (e.g. changes in phenology and pollinator visitation) in maintaining reproductive isolation between newly arisen selfing populations and their outcrossing ancestors? To test whether changes in phenology and pollinator visitation isolate selfing populations of Arabidopsis lyrata from outcrossing populations, we conducted a common garden experiment with plants from selfing and outcrossing populations as well as their between-population hybrids. Specifically, we asked whether there was isolation between outcrossing and selfing plants and their between-population hybrids through differences in (1) the timing or intensity of flowering; and/or (2) pollinator visitation. We found that phenology largely overlapped between plants from outcrossing and selfing populations. There were also no differences in pollinator preference related to mating system. Additionally, pollinators preferred to visit flowers on the same plant rather than exploring nearby plants, creating a large opportunity for self-fertilization. Overall, this suggests that pre-zygotic pre-pollination mechanisms do not strongly reproductively isolate plants from selfing and outcrossing populations of Arabidopsis lyrata .

scholarly journals Can Sexual Selection Cause Divergence in Mating System-Related Floral Traits?

2019 ◽  
Author(s):  
Åsa Lankinen ◽  
Maria Strandh
Keyword(s):  
Sexual Selection ◽  
Mating System ◽  
Experimental Evolution ◽  
Seed Set ◽  
Pollen Competition ◽  
Floral Traits ◽  
Mixed Mating ◽  
Stigma Receptivity ◽  
Source Line ◽  
Outcrossing Species

AbstractPremise of the ResearchThe wide diversity of floral traits seen among plants is shaped by neutral and selective evolutionary processes. In outcrossing species, sexual selection from competing pollen donors is expected to be important for shaping mating system-related traits but empirical evidence is scarce. In a previous evaluation of experimental evolution lines crossed with either one or two pollen donors (monogamous, M, or polyandrous, P, lines) at early floral stages in mixed-mating Collinsia heterophylla (Plantaginaceae), P showed enhanced pollen competitive ability and reduced maternal seed set compared to M, in accordance with sexually antagonistic evolution of pollen. Here, we asked whether the presence of sexual selection during pollen competition affect mating system-related floral traits in the same lines.MethodologyWe compared flowering start, timing of anther-stigma contact (as an indication of timing of self-pollination), timing of stigma receptivity and first seed set between M and P, and with a source line, S (starting material). The former three traits are later in outcrossers than in selfers of Collinsia. The latter trait was expected to be earlier in P than in M because of sexual selection for early seed siring of pollen.Pivotal ResultsArtificial polyandry for four generations resulted in later flowering start and later anther-stigma contact in P compared to M, and the latter trait was intermediate in S. Thus, P appeared more ‘outcrossing’ than M. Stigma receptivity did not differ between lines. First seed set was earlier in P than in M, as expected from sexual selection.ConclusionsOur results from C. heterophylla experimental evolution lines suggest that a component of sexual selection during outcross pollination could enhance the patterns of floral divergence commonly found between outcrossers and selfers.

scholarly journals Rapid and recent allopatric speciation in firs from central Mexico: evidence for reinforcement?

2021 ◽  
Author(s):  
Gustavo Giles-Pérez ◽  
Erika Aguirre-Planter ◽  
Luis Eguiarte ◽  
Juan Jaramillo-Correa
Keyword(s):  
Reproductive Isolation ◽  
Volcanic Belt ◽  
Secondary Contact ◽  
Reproductive Phenology ◽  
Central Mexico ◽  
Sky Islands ◽  
Hybrid Fitness ◽  
Mexican Volcanic Belt ◽  
History Of ◽  
Self Fertilization

Secondary contact of species that have evolved partial reproductive isolation in allopatry may result in several outcomes, which range from rampant hybridization to barrier reinforcement. Reinforcement arises from reduced hybrid fitness, which promotes assortative mating and hence speciation. In plants, self-fertilization and disjunctions in reproductive-phenology are often invoked as evidence of reinforcement. However, local adaptation and pleiotropic effects during colonization can also lead to reproductive isolation without reinforcement. We explored these possibilities in a fir species complex (Abies flinckii - A. religiosa) distributed in ‘sky-islands’ along the Trans-Mexican Volcanic Belt (TMVB), in central Mexico. Despite co-occurring in two independent sympatric regions (west and center), these two taxa seem to rarely interbreed because of disjunct reproductive phenologies. We genotyped 1,147 SNPs, generated by GBS across 23 populations, and compared multiple demographic scenarios, built based on the geological history of the TMVB. The best-fitting model suggested a recent species split (for a conifer), dating back to ~1.2 Ma, together with early asymmetric gene flow (mostly from A. flinckii into A. religiosa), limited to the central sympatric region. Coupled with the lack of support for colonization models, the summary statistics (f, Hobs, FST, θπ, etc.) and historical demographic inferences made herein point to a rapid speciation with an early development of reinforcement, as a putative mechanism for avoiding hybridization. The role of reinforcement should be thus further explored in the (sub)tropics, as likely explanation for how species diversity is generated and maintained.

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