Intraspecific interactions in the annual legume Medicago minima are shaped by both genetic variation for competitive ability and reduced competition among kin

2021 ◽  
Author(s):  
Sara Tomiolo ◽  
Claire Thomas ◽  
Michael K. Jespersen ◽  
Christian F. Damgaard ◽  
Bodil K. Ehlers
Keyword(s):  
Genetic Variation ◽  
Competitive Ability ◽  
Intraspecific Interactions

scholarly journals Intraspecific interactions in the annual legume Medicago minima are shaped by both genetic variation for competitive ability and reduced competition among kin

2019 ◽  
Author(s):  
Sara Tomiolo ◽  
Claire Thomas ◽  
Michael K. Jespersen ◽  
Christian F. Damgaard ◽  
Bodil K. Ehlers
Keyword(s):  
Genetic Variation ◽  
Competitive Ability ◽  
Inclusive Fitness ◽  
Spatial Scales ◽  
Competitive Growth ◽  
Intraspecific Interactions ◽  
Intraspecific Interaction ◽  
Diversity Maintenance ◽  
Competition Avoidance ◽  
Genetic Substructure

AbstractKnowing which mechanisms drive the outcome of intraspecific interactions is highly relevant for understanding diversity maintenance. Plant species that exhibit strong genetic substructure over small spatial scales may be exposed to frequent interactions with closely related individuals. Predictions of how genetic similarity may drive the outcome of intraspecific interactions are based on two contrasting theories: the resource partitioning hypothesis and kin selection theory. The first predicts that competition will be stronger among closely related conspecific (i.e. kin) because similar genotypes have similar resource requirements. The second predicts instead that competition will be reduced among kin, in order to maximize the inclusive fitness. Although efforts have been made to reconcile these two theories as non-mutually exclusive, the outcomes of intraspecific interaction studies are frequently interpreted as the results of either one or the other. We experimentally tested the hypothesis that intraspecific interactions may be driven by both genetic variation for competitive ability and reduced competition among kin. We used an annual legume, Medicago minima, to conduct two greenhouse experiments testing changes in root behaviour, above-ground growth and biomass in response to neighbour identity. We found evidence of both genetic variation for competitive ability and reduced competition among kin in some genotypes. Reduced competitive growth towards kin was found in the most competitive genotypes, suggesting that kin avoidance and competitive ability were simultaneously affecting plant behaviour and growth. With presence of both kin competition avoidance and variation for competitive ability, the outcome of intraspecific interactions will strongly depend on the local spatial genetic substructure. This is highly relevant to predict how intraspecific competition affect diversity maintenance.

scholarly journals Rapid evolution of weedy traits during sunflower de-domestication: the importance of hybridization and standing genetic variation

2021 ◽  
Author(s):  
Fernando Hernandez ◽  
Roman Boris Vercellino ◽  
Claudio Pandolfo ◽  
Jennifer R. Mandel ◽  
Alejandro Presotto
Keyword(s):  
Genetic Diversity ◽  
Genetic Variation ◽  
Seed Dormancy ◽  
Herbicide Resistance ◽  
Competitive Ability ◽  
Management Strategies ◽  
Rapid Evolution ◽  
High Genetic Diversity ◽  
Herbicide Resistant ◽  
Evolution Of Resistance

Hybridization between crops and their wild relatives may promote the evolution of de-domesticated (feral) weeds. Wild sunflower is typically found in ruderal environments, but crop-wild hybridization may facilitate the evolution of weedy biotypes. Using one crop-specific mitochondrial marker (CMS-PET1) and 14 nuclear SSR markers, we studied the origin and genetic diversity of BRW, a recently discovered weedy biotype. Then, using a resurrection approach, we tested for rapid evolution of weedy traits (seed dormancy, herbicide resistance, and competitive ability) by sampling weedy and wild biotypes 10 years apart (2007 and 2017). All the weedy plants present the CMS-PET1 cytotype, confirming their feral origin. At the nuclear markers, BRW showed higher genetic diversity than the cultivated lines, as high genetic diversity as the most diverse wild biotypes, and low differentiation with one wild biotype, suggesting that wild hybridization increased the genetic diversity of the feral BRW. Regarding weedy trait evolution, we found support for rapid evolution towards higher seed dormancy, but not for higher competitive ability or herbicide resistance. Standing genetic variation probably facilitated the evolution of seed dormancy and limited the evolution of herbicide resistance, as no resistant alleles were found in the ancestral biotype. Our results demonstrate that natural crop-wild hybrids can evolve quickly in farmers' fields, leading to the establishment of weedy biotypes of cultivated origin. Although herbicide resistance did not evolve in BRW, management strategies aimed at preventing the evolution of resistance should be a priority in order to avoid the emergence and spread of herbicide resistant biotypes in Argentina.

scholarly journals Variation in the root mass of ryegrass types and its ecological consequences.

1983 ◽  
Vol 31 (4) ◽  
pp. 325-334
Author(s):  
G.C. Ennik ◽  
T.B. Hofman
Keyword(s):  
Genetic Variation ◽  
Root Growth ◽  
Perennial Ryegrass ◽  
Environmental Conditions ◽  
Competitive Ability ◽  
Italian Ryegrass ◽  
Root Mass ◽  
Shoot:Root Ratio ◽  
N Supply ◽  
Defoliation Frequency

The shoot:root ratio of Italian ryegrass and perennial ryegrass cv. in the vegetative phase was constant under constant conditions. With intermittent N supply, root mass and shoot:root ratio of ryegrass in monoculture varied widely. Both relatively and absolutely, root mass was larger than with constant N supply. Short periods of low N were sufficient for a marked increase in root growth. Under constant environmental conditions root mass was closely related to defoliation frequency. Considerable genetic variation in root mass existed between perennial ryegrass clones. Differences were largest under conditions of max. root growth. Root mass was positively related to competitive ability. (Abstract retrieved from CAB Abstracts by CABI’s permission)

scholarly journals Nutrient Environments Influence Competition among Aspergillus flavus Genotypes

2012 ◽  
Vol 79 (5) ◽  
pp. 1473-1480 ◽  
Author(s):  
Hillary L. Mehl ◽  
Peter J. Cotty
Keyword(s):  
Aspergillus Flavus ◽  
Mycelial Growth ◽  
Competitive Ability ◽  
Aflatoxin Contamination ◽  
Nucleotide Polymorphisms ◽  
Intraspecific Interactions ◽  
Single Nucleotide ◽  
Content Type ◽  
Agar Media ◽  
Nutrient Variability

ABSTRACTThe population dynamics ofAspergillus flavus, shaped in part by intraspecific competition, influence the likelihood and severity of crop aflatoxin contamination. Competition for nutrients may be one factor modulating intraspecific interactions, but the influences of specific types and concentrations of nutrients on competition between genotypes ofA. flavushave not been investigated. Competition between pairedA. flavusisolates on agar media was affected by varying concentrations of carbon (sucrose or asparagine) and nitrogen (nitrate or asparagine). Cocultivated isolate percentages from conidia and agar-embedded mycelia were quantified by measurements of isolate-specific single-nucleotide polymorphisms with quantitative pyrosequencing. Compositions and concentrations of nutrients influenced conidiation resulting from cocultivation, but the percentages of total conidia from each competing isolate were not predicted by sporulation of isolates grown individually. Success during sporulation did not reflect the outcomes of competition during mycelial growth, and the extents to which isolate percentages from conidia and mycelia differed varied among both isolate pairs and media. Whether varying concentrations of sucrose, nitrate, or asparagine increased, decreased, or had no influence on competitive ability was isolate dependent. Different responses ofA. flavusisolates to nutrient variability suggest genotypes are adapted to different nutrient environments that have the potential to influenceA. flavuspopulation structure and the epidemiology of aflatoxin contamination.

scholarly journals A QTL analysis of female variation contributing to refractoriness and sperm competition in Drosophila melanogaster

2005 ◽  
Vol 86 (2) ◽  
pp. 107-114 ◽  
Author(s):  
MARA K. N. LAWNICZAK ◽  
DAVID J. BEGUN
Keyword(s):  
Drosophila Melanogaster ◽  
Genetic Variation ◽  
Sperm Competition ◽  
Competitive Ability ◽  
Recombinant Inbred Lines ◽  
Inbred Lines ◽  
Phenotypic Variance ◽  
Fitness Component ◽  
Male Sperm ◽  
Trait Locus

Sperm competition is an important fitness component in many animal groups. Drosophila melanogaster males exhibit substantial genetic variation for sperm competitive ability and females show considerable genetic variation for first versus second male sperm use. Currently, the forces responsible for maintaining genetic variation in sperm competition related phenotypes are receiving much attention. While several candidate genes contributing to the variation seen in male competitive ability are known, genes involved in female sperm use remain largely undiscovered. Without knowledge of the underlying genes, it will be difficult to distinguish between different models of sexual selection such as cryptic female choice and sexual conflict. We used quantitative trait locus (QTL) mapping to identify regions of the genome contributing to female propensity to use first or second male sperm, female refractoriness to re-mating, and early-life fertility. The most well supported markers influencing the phenotypes include 33F/34A (P2), 57B (refractoriness) and 23F/24A (fertility). Between 10% and 15% of the phenotypic variance observed in these recombinant inbred lines was explained by these individual QTLs. More detailed investigation of the regions detected in this experiment may lead to the identification of genes responsible for the QTLs identified here.

scholarly journals Eco-evolutionary interaction in competing phytoplankton: genotype sorting likely explains dominance shift and species responses to CO2

2020 ◽  
Author(s):  
Luisa Listmann ◽  
Giannina S. I. Hattich ◽  
Birte Matthiessen ◽  
Thorsten B.H. Reusch
Keyword(s):  
Climate Change ◽  
Genetic Variation ◽  
Competitive Ability ◽  
Phytoplankton Community ◽  
Phytoplankton Species ◽  
Community Responses ◽  
Evolutionary Selection ◽  
Parsimonious Explanation ◽  
Over Time

AbstractHow ecological and evolutionary processes interact and together determine species and community responses to climate change is poorly understood. We studied long-term dynamics (over approximately 200 asexual generations) in two phytoplankton species, a coccolithophore (Emiliania huxleyi) and a diatom (Chaetoceros affinis), to increased CO2 growing alone or competing with one another in co-occurrence. To allow for rapid evolutionary responses, the experiment started with a standing genetic variation of nine genotypes in each of the species. Under co-occurrence of both species, we observed a dominance shift from C. affinis to E. huxleyi after about 120 generations in both CO2 treatments, but more pronounced under high CO2. Associated with this shift, we only found weak adaptation to high CO2 in the diatom and none in the coccolithophore in terms of species’ growth rates. In addition, no adaptation to interspecific competition could be observed by comparing the single to the two-species treatments in reciprocal assays, regardless of the CO2 treatment. Nevertheless, highly reproducible genotype sorting left only one genotype remaining for each of the species among all treatments. This strong evolutionary selection coincided with the dominance shift from C. affinis to E. huxleyi. Since all other conditions were kept constant over time, the most parsimonious explanation for the dominance shift is that the strong evolutionary selection potentially altered competitive ability of the two species. Thus, here observed changes in the simplest possible two-species phytoplankton “community” demonstrated that eco-evolutionary interactions can be critical for predicting community responses to climate change in rapidly dividing organisms such as phytoplankton.

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