scholarly journals Pollinator-Mediated Selection on Floral Traits in the Arctic Plant Parrya nudicaulis (Brassicaceae)

2021 ◽  
Author(s):  
Matthew Carlson ◽  
Justin Fulkerson
Keyword(s):  
Flower Color ◽  
Phenotypic Selection ◽  
Directional Selection ◽  
The Arctic ◽  
Floral Traits ◽  
Reproductive Assurance ◽  
Pollinator Attraction ◽  
Selection Gradients ◽  
Selective Agents ◽  
Selection For

The evolution of floral traits is largely attributed to pollinator-mediated selection; however, the importance of pollinators as selective agents in pollen-limited environments is poorly resolved. In pollen-limited arctic and subarctic regions, selection is expected to either favor floral traits that increase pollinator attraction or promote reproductive assurance through selfing. We quantified phenotypic selection on floral traits in two arctic and two subarctic populations of Parrya nudicaulis. Additionally, we measured selection in plants in both open-pollination and pollen-augmentation treatments to estimate selection imposed by pollinators in one population. Seed production was found to be limited by pollen availability and strong directional selection on flower number was observed. We did not detect consistently greater magnitudes of selection on floral traits in the arctic relative to the subarctic populations. Directional selection for more pigmented flowers in one arctic population was observed however. In some populations, selection on flower color was found to interact with other traits. We did not detect consistently stronger selection gradients across all traits for plants exposed to pollinator selection relative to those in the pollen-augmentation treatment; however directional selection tended to be higher for some floral traits in open-pollinated plants.

scholarly journals Self-Compatibility Not Associated with Morphological or Genetic Diversity Reduction in Oil-Rewarding Calceolaria Species

Plants ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 1377
Author(s):  
Maureen Murúa ◽  
Anahí Espíndola ◽  
Fernanda Pérez
Keyword(s):  
Genetic Diversity ◽  
Floral Biology ◽  
The Self ◽  
Floral Traits ◽  
Reproductive Assurance ◽  
Pollinator Attraction ◽  
Evolutionary Transitions ◽  
Allele Number ◽  
Self Compatibility ◽  
Study Species

One of the most common evolutionary transitions in angiosperms is the reproductive change from outcrossing to selfing, commonly associated with changes in floral biology and genetic diversity. Here, we aim to test whether self-compatibility leads to a reduction of floral traits and genetic diversity. For this, we experimentally estimate levels of self-compatibility, measure three floral traits and estimate four genetic diversity parameters using nine microsatellites in nine Calceolaria species. Our analysis indicated that four of the study species were self-incompatible. In addition, we found that self-compatible species did not show a reduction in floral traits size, but rather displayed larger corolla and elaiophore areas. Our analyses of genetic diversity identified larger allele number and observed heterozygosity in selfers than in outcrossers, but did not find larger inbreeding in the self-compatible species. Even though our results contradict our expectations, in the case of Calceolaria, their high dependence on only two genera of oil-bees puts the genus in a vulnerable reproductive position, probably facilitating the evolution of reproductive assurance mechanisms in the absence of pollinators. As a result, plants maintain their pollinator attraction traits while evolving the ability to self, possibly in a delayed way.

Effect of coflowering Mimulus ringens on phenotypic selection on floral traits of gynodioecious Lobelia siphilitica

Botany ◽  
2013 ◽  
Vol 91 (11) ◽  
pp. 745-751 ◽  
Author(s):  
Erica Wassink ◽  
Christina M. Caruso
Keyword(s):  
Seed Set ◽  
Flower Colour ◽  
Phenotypic Selection ◽  
Character Displacement ◽  
Floral Traits ◽  
Competition For Pollination ◽  
Mimulus Ringens ◽  
Potential Competitor ◽  
Selection For ◽  
Presence And Absence

Although interspecific competition for pollination is hypothesized to result in divergence in floral traits (i.e., character displacement), few studies have tested whether selection on these traits differs in the presence and absence of a competitor for pollination. We measured phenotypic selection on floral traits of Lobelia siphilitica L. growing in the presence and absence of Mimulus ringens L., a potential competitor for pollination. Because L. siphilitica is gynodioecious, we estimated selection separately for female and hermaphrodite plants. The presence of M. ringens did not decrease seed set of L. siphilitica. However, the presence of M. ringens did affect selection on daily display size of female L. siphilitica; there was significant selection for smaller daily displays in the absence of M. ringens, but nonsignificant selection for larger displays in the presence of M. ringens. In addition, selection on flower colour did not differ in the presence and absence of M. ringens, but did differ between female and hermaphrodite L. siphilitica. Consequently, our results suggest that the evolution of floral traits in L. siphilitica, but not the evolution of sexual dimorphism in these traits, can be affected by interactions for pollination with M. ringens.

Shift in flowering time allows diploid and autotetraploid Anacamptis pyramidalis (Orchidaceae) to coexist by reducing competition for pollinators

2019 ◽  
Vol 191 (2) ◽  
pp. 274-284 ◽  
Author(s):  
Luca Pegoraro ◽  
Jurriaan M De Vos ◽  
Salvatore Cozzolino ◽  
Giovanni Scopece
Keyword(s):  
Reproductive Success ◽  
Flowering Time ◽  
Phenotypic Selection ◽  
Fruit Production ◽  
Floral Traits ◽  
Flower Number ◽  
Late Flowering ◽  
Flower Traits ◽  
Anacamptis Pyramidalis ◽  
Selection For

Abstract How autopolyploids establish when competing with diploid progenitors is still poorly understood. Here, we investigate the effects of morphological and phenological divergence on the reproductive success of co-occurring diploid and autotetraploid individuals of Anacamptis pyramidalis to disentangle the mechanisms allowing their c-oexistence. We estimated reproductive success in terms of absolute and relative fruit production and recorded morphological and phenological traits of the two cytotypes. We also estimated correlations between traits within cytotypes and the related phenotypic selection patterns. The two cytotypes experience similar levels of reproductive success, but they differ significantly in their morphological and phenological traits. Correlations among floral traits were weaker in autotetraploids than in diploids, but among-individuals variation was higher in diploids. For most flower traits, the strength of phenotypic selection was different in the two cytotypes. We found selection on flower number in both cytotypes, whereas selection for earlier flowering time was only found in late-flowering diploids. Our results suggest that a shift in flowering time may have allowed diploid and autotetraploid A. pyramidalis individuals to reduce competition for naïve pollinators. Consequently, the two cytotypes can coexist by attaining similar levels of reproductive success and, at same time, reducing the likelihood of inter-cytotype mating.

scholarly journals Phenotypic Selection on Flower Color and Floral Display Size by Three Bee Species

2021 ◽  
Vol 11 ◽  
Author(s):  
Johanne Brunet ◽  
Andrew J. Flick ◽  
Austin A. Bauer
Keyword(s):  
Plant Species ◽  
Display Size ◽  
Flower Color ◽  
Phenotypic Selection ◽  
Floral Traits ◽  
Floral Display ◽  
Floral Trait ◽  
Correlational Selection ◽  
Floral Display Size ◽  
Plant Level

Plants exhibit a wide array of floral forms and pollinators can act as agent of selection on floral traits. Two trends have emerged from recent reviews of pollinator-mediated selection in plants. First, pollinator-mediated selection on plant-level attractants such as floral display size is stronger than on flower-level attractant such as flower color. Second, when comparing plant species, distinct pollinators can exert different selection patterns on floral traits. In addition, many plant species are visited by a diverse array of pollinators but very few studies have examined selection by distinct pollinators. In the current study, we examined phenotypic selection on flower color and floral display size by three distinct bee species, the European honey bee, Apis mellifera, the common eastern bumble bee, Bombus impatiens, and the alfalfa leafcutting bee, Megachile rotundata, foraging on Medicago sativa. To estimate phenotypic selection by each bee species and for all bees combined simultaneously and on the same group of plants, we introduce a new method that combines pollinator visitation data to seed set and floral trait measurements data typical of phenotypic selection study. When comparing floral traits, all bee species selected on the number of racemes per stem and the number of stems per plant, two components of floral display size. However, only leafcutting bees selected on hue or flower color and only bumble bees selected on chroma or darkness of flowers. Selection on chroma occurred via correlational selection between chroma and number of open flowers per raceme and we examine how correlational selection may facilitate the evolution of flower color in plant populations. When comparing bee species, the three bee species exerted similar selection pattern on some floral traits but different patterns on other floral traits and differences in selection patterns were observed between flower-level and plant-level attractants. The trends detected were consistent with previous studies and we advocate the approach introduced here for future studies examining the impact of distinct pollinators on floral trait evolution.

Recurrent Phenotypic Selection for Resistance to Brown Leaf Spot in Smooth Bromegrass 1

Crop Science ◽  
1986 ◽  
Vol 26 (3) ◽  
pp. 533-536 ◽  
Author(s):  
Clyde C. Berg ◽  
Robert T. Sherwood ◽  
Kenneth E. Zeiders
Keyword(s):  
Leaf Spot ◽  
Phenotypic Selection ◽  
Smooth Bromegrass ◽  
Brown Leaf Spot ◽  
Brown Leaf ◽  
Selection For

scholarly journals Substitution Rates Under Stabilizing Selection

Genetics ◽  
1987 ◽  
Vol 116 (3) ◽  
pp. 479-486
Author(s):  
Alan Hastings
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
Quantitative Traits ◽  
Strong Dependence ◽  
Phenotypic Selection ◽  
Analytical Models ◽  
Stabilizing Selection ◽  
Substitution Rates ◽  
Quantitative Characters ◽  
Selection For

ABSTRACT Allelic substitutions under stabilizing phenotypic selection on quantitative traits are studied in Monte Carlo simulations of 8 and 16 loci. The results are compared and contrasted to analytical models based on work of M. Kimura for two and "infinite" loci. Selection strengths of S = 4Nes approximately four (which correspond to reasonable strengths of selection for quantitative characters) can retard substitution rates tenfold relative to rates under neutrality. An important finding is a strong dependence of per locus substitution rates on the number of loci.

Genetics and breeding of Sitka spruce

1987 ◽  
Vol 93 (1-2) ◽  
pp. 41-50
Author(s):  
Roy Faulkner
Keyword(s):  
Phenotypic Selection ◽  
Sitka Spruce ◽  
Interspecific Hybridisation ◽  
Family Selection ◽  
Short Term ◽  
Improvement Programme ◽  
Important Trait ◽  
Clonal Testing ◽  
Selection For ◽  
Old Trees

SynopsisSitka spruce is a monoecious, wind-pollinated, cross-fertilising species showing wide genetic variation which suggests heterozygosity for many alleles and natural selection against self-fertilisation. Phenotypic selection for the important trait of vigour is ineffective, so testing progenies of selected individuals and clonal testing is an essential and time-consuming part of any improvement programme. Old trees can be vegetatively propagated by grafting and very young trees by rooted cuttings.The British tree improvement programme is based, in the short term, on the use of seed collected from superior plantation trees of desirable origins; in the mid term on seed derived from clonal orchards based on mixtures of clones previously tested for superiority in family tests; and in the longer term on highly superior seed or clones derived from a system of recurrent mating with family selection. Three populations are being developed. There is a small interspecific hybridisation programme.

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