THE ROLE OF INBREEDING DEPRESSION IN MAINTAINING THE MIXED MATING SYSTEM OF THE COMMON MORNING GLORY,IPOMOEA PURPUREA

Evolution ◽  
1999 ◽  
Vol 53 (5) ◽  
pp. 1366-1376 ◽  
Author(s):  
Shu-Mei Chang ◽  
Mark D. Rausher
Keyword(s):  
Mating System ◽  
Inbreeding Depression ◽  
Morning Glory ◽  
Mixed Mating ◽  
Mixed Mating System ◽  
Ipomoea Purpurea ◽  
The Common

Glyphosate induces transient male sterility in Ipomoea purpurea

Botany ◽  
2008 ◽  
Vol 86 (6) ◽  
pp. 587-594 ◽  
Author(s):  
Regina S. Baucom ◽  
Rodney Mauricio ◽  
Shu-Mei Chang
Keyword(s):  
Male Sterility ◽  
Lethal Dose ◽  
Female Fertility ◽  
Morning Glory ◽  
Response To Treatment ◽  
Mixed Mating ◽  
Mixed Mating System ◽  
Ipomoea Purpurea ◽  
Female Function ◽  
Common Effect

Plant death is the most common effect resulting from the application of glyphosate, the active ingredient in the herbicide Roundup®. Individual seedlings of the morning glory, Ipomoea purpurea L. Roth, however, have been shown to exhibit tolerance to glyphosate, surviving after what should have been a lethal dose. Those that grow and reach reproductive maturity often exhibit deformed anthers within what appear to be normally developed flowers. Ipomoea purpurea has a mixed mating system and normally has hermaphroditic flowers that are capable of both selfing and outcrossing. The deformed anthers do not produce pollen, essentially converting a hermaphroditic flower to a female. Here we describe this morphological change and investigate the reproductive consequences of anther deformation. First, there is phenotypic variation for the propensity of an individual to exhibit male sterility through deformed anthers in response to treatment, but a series of field and greenhouse studies suggest that this variation is not genetic. The male sterility is also transient; within an individual, the frequency of flowers with deformed anthers declines over time. Although flowers with deformed anthers do not produce pollen, we observed mixed effects on female function of such flowers. In the greenhouse, flowers with deformed anthers that were hand-pollinated produced as many seeds as flowers with normal anthers, suggesting no effect on female fertility. In the field, however, plants with a higher proportion of anther deformation set significantly fewer seeds than those untreated, suggesting either reduced female fertility, or a reproductive penalty in flowers with deformed anthers due to the inability to self pollinate. Thus, the presence of this trait could alter the selfing to outcrossing ratio in populations that are sprayed with the herbicide. Individuals that exhibited a higher proportion of anther deformation also produce fewer total flowers than untreated plants, suggesting that anther deformation is part of a suite of responses to damage by glyphosate.

scholarly journals Life cycle expression of inbreeding depression in Eucalyptus regnans and inter-generational stability of its mixed mating system

2019 ◽  
Vol 124 (1) ◽  
pp. 179-187 ◽  
Author(s):  
A Rod Griffin ◽  
Brad M Potts ◽  
René E Vaillancourt ◽  
J Charles Bell
Keyword(s):  
Life Cycle ◽  
Mating System ◽  
Inbreeding Depression ◽  
Field Experiments ◽  
Natural Populations ◽  
Forest Tree ◽  
Mixed Mating ◽  
Mature Trees ◽  
Mixed Mating System ◽  
Eucalyptus Regnans

Abstract Background and Aims Many plants exhibit a mixed mating system. Published models suggest that this might be an evolutionarily stable rather than a transitional state despite the presence of inbreeding depression, but there is little empirical evidence. Through field experimentation, we studied the role of inbreeding depression in eliminating inbred progeny from the reproductive cohort of the forest tree Eucalyptus regnans, and demonstrate a stable mixed primary mating system over two successive generations. Methods Two field experiments were conducted using seed from natural populations. We sowed open-pollinated seeds to simulate a natural regeneration event and determined isozyme genotypes of dominant and suppressed individuals over 10 years. We also planted a mixture of open-pollinated, outcross and selfed families with common maternal parentage; monitored survival of cross types over 29 years; and determined the percentage of outcrosses in open-pollinated seed from a sample of reproductively mature trees using microsatellite analysis. Key Results Both experiments demonstrated progressive competitive elimination of inbred plants. By 29 years, the reproductive cohort in the planted experiment consisted only of outcrosses which produced seed which averaged 66 % outcrosses, similar to the estimate for the parental natural population (74 %). Conclusions Selective elimination of inbred genotypes during the intense intra-specific competition characteristic of the pre-reproductive phase of the life cycle of E. regnans results in a fully outcrossed reproductive population, in which self-fertility is comparable with that of its parental generation. The mixed mating system may be viewed as an unavoidable consequence of the species’ reproductive ecology, which includes the demonstrated effects of inbreeding depression, rather than a strategy which is actively favoured by natural selection.

Mating system of Calluna vulgaris: self-sterility and outcrossing estimations

1998 ◽  
Vol 76 (1) ◽  
pp. 37-42 ◽  
Author(s):  
Grégory Mahy ◽  
Anne-Laure Jacquemart
Keyword(s):  
Mating System ◽  
Inbreeding Depression ◽  
Calluna Vulgaris ◽  
Pollen Tubes ◽  
Outcrossing Rate ◽  
Evolutionary Significance ◽  
Mixed Mating ◽  
Mixed Mating System ◽  
Cross Pollination ◽  
Mating System Evolution

The evolutionary significance of a mixed mating system is currently under debate. Calluna vulgaris (L). Hull, a widespread European shrub, is likely to undergo mixed mating because of geitonogamy. Mating system was investigated in three populations of C. vulgaris by means of greenhouse controlled crosses, pollen tube observations, and outcrossing rate estimations from allozyme markers. The species is highly self-sterile, most probably as a result of early inbreeding depression. Mean fruit set and mean seed number per fruit following hand self-pollination were 48 and 13%, respectively, of those following cross-pollination. Pollen tubes produced by self pollen penetrated the ovary with the same success as those from cross-pollination. Multilocus estimates of the outcrossing rates ranged from 0.71 to 0.90, and two estimates were significantly different from 1.00. Calluna vulgaris could thus be classified as being mixed mating with predominant allogamy. Single-locus estimates did not differ significantly from multilocus estimates suggesting that biparental inbreeding did not contribute to the apparent selfing rate. The maintenance of high early inbreeding depression despite an intermediate level of selfing is discussed with respect to recent theories on mating system evolution. Key words: Calluna vulgaris, mating system, self-sterility, pollen tubes, outcrossing rate, inbreeding depression.

scholarly journals Outbreeding and possibly inbreeding depression in a pollinating fig wasp with a mixed mating system

Heredity ◽  
2009 ◽  
Vol 102 (4) ◽  
pp. 349-356 ◽  
Author(s):  
J M Greeff ◽  
G J Jansen van Vuuren ◽  
P Kryger ◽  
J C Moore
Keyword(s):  
Mating System ◽  
Inbreeding Depression ◽  
Mixed Mating ◽  
Fig Wasp ◽  
Mixed Mating System

scholarly journals Environmental influences on the mating system of the common morning glory

2017 ◽  
Author(s):  
D. F. Alvarado-Serrano ◽  
S-M. Chang ◽  
R. S Baucom
Keyword(s):  
Environmental Factors ◽  
Mating System ◽  
Population Level ◽  
Mating Strategies ◽  
Morning Glory ◽  
Life History Trait ◽  
Mixed Mating ◽  
Model Free ◽  
System Components ◽  
The Common

ABSTRACTThe balance between selfing and outcrossing is a life history trait of major concern with deep evolutionary consequences in mixed mating species. Yet, our current understanding of the proximate and ultimate determinants of species’ mating system is still unsatisfactory and largely theoretical. Indeed, evolutionary biologists are still puzzled by the often dramatic variation of mating strategies within single species. Of particular concern is the extent to which environmental conditions shape patterns of variation and covariation of mating system components within species. Here, we address this concern in the common morning glory (Ipomoea purpurea) by taking advantage of an extensive dataset of floral traits, genetic estimates of selfing and inbreeding, and relevant environmental factors compiled for 22 populations of this species distributed along a disparate set of environments along Southeast and Midwest USA. Combining a powerful array of parametric and model-free statistical approaches, we robustly identify a set of natural and anthropogenic environmental factors underlying population-level variation in selfing, inbreeding, and flower morphology. Remarkably, individual mating system components are found to be associated with different environmental factors and only loosely associated with each other, and thus potentially under multiple different selective pressures. These results not only corroborate theoretical expectations of the significant role the environment plays in the local determination of mating systems, but also provide compelling evidence of complex underlying interactions between multiple evolutionary processes.

scholarly journals A stochastic model of selection on selfing rates in structured populations

1995 ◽  
Vol 65 (3) ◽  
pp. 209-222 ◽  
Author(s):  
J. Ronfort ◽  
D. Couvet
Keyword(s):  
Population Structure ◽  
Stochastic Model ◽  
Mating System ◽  
Inbreeding Depression ◽  
Structured Populations ◽  
Empirical Literature ◽  
Mixed Mating ◽  
Selfing Rate ◽  
Mixed Mating System ◽  
Biparental Inbreeding

SummaryPrevious theoretical studies of the evolution of the selfing rate have shown that mixed mating systems are not evolutionary stable states. Such models have, however, not included the effects of population structure and thus biparental inbreeding together with the evolution of selfing rates and inbreeding depression. In order to examine selection on selfing rates in structured populations, a stochastic model simulating a finite population with partial selfing and restricted pollen and seed dispersal has been developed. Selection on the mating system was followed by introducing modifiers affecting the selfing rate. The major result was that, with density dependent recruitment, a process which maintains the population structure necessary for biparental inbreeding to occur, a mixed mating system could be maintained. This result was associated with an increase of the mutation load with high selfing rates, and the selected selfing rate depended on the degree of population structure rather than on the initial selfing rate. With low dominance of deleterious alleles, complete allogamy can be selected for. Further studies showed that the more general condition of spatial heterogeneity of recruitment can lead to similar results, the most important condition being the maintenance of genetic structure within populations. A brief survey of the empirical literature shows that a positive relationship between the magnitude of inbreeding depression and the inbreeding coefficient within populations has been observed, in support of the present model.

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