The Effect of Inbreeding on Seed Survivorship in Phlox

Levin, Donald A.

doi:10.2307/2409708

Cited by 15 publications

(9 citation statements)

References 7 publications

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“…For example, seed set resulting from the selfed and outcrossed pollinations was not measured in this study. Inbreeding depression acting at this early stage, caused by differential fertilization and/ or seed abortion, has been detected in many studies (Jam, 1978;Price & Waser, 1979;Schemske, 1983;Schemske & Pautler, 1984;Levin, 1989Levin, , 1991Kohn, 1988;Stevens & Bougourd, 1988;Dudash, 1990;Manasse & Pinriey, 1991;Weller & Ornduff, 1991) but not in other studies (Schemske, 1983;Schoen, 1983;Karron, 1989;Levin, 1989;Holtsford & Ellstrand, 1990). Male fertility is another major fitness component that was not measured in this study.…”

Section: Discussionmentioning

confidence: 53%

Partial self-fertilization and inbreeding depression in two populations of Mimulus guttatus

1993

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Inbreeding depression is likely to be a common selective force opposing the automatic selective advantage of self-fertilization in self-compatible plants and animals, yet relatively few studies have measured both the breeding system and inbreeding depression in natural populations. In this study, I estimated the frequency of selfing, using data obtained by gel electrophoresis, in two annual populations of the monkeyflower Mimulus guuatus for 2 years, and measured the relative performance of selfed and outcrossed progeny over several stages of the life cycle in both the field and the greenhouse. Rates of outcrossing were not significantly different from 1.0 in either population in 1989, but both populations exhibited significant and moderate amounts of selfing in 1990. Outcrossing rates were significantly different between years for the Cone Peak population but not for the Iron Mountain population. Significant inbreeding depression was detected for almost every component of fitness measured, including germination success, survival to flowering, and flower, fruit and seed production in the native field enviromnents for both populations. The final cumulative value of inbreeding depression, calculated as one minus the relative total seed production of selfed to outcrossed progeny, was 0.69 for Iron Mountain and 0.64 for Cone Peak.Inbreeding depression was also severe in the greenhouse experiments, even though fitness components only up to flower production were measured: 0.52 for Iron Mountain and 0.48 for Cone Peak. These results are consistent with theoretical predictions of the magnitude of inbreeding depression in primarily outcrossing populations, and indicate that inbreeding depression is an important factor in the maintenance of outcrossing in these populations.

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Section: Discussionmentioning

confidence: 53%

Partial self-fertilization and inbreeding depression in two populations of Mimulus guttatus

1993

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“…In E. paniculata, Barrett and Charlesworth (1991) found the fitness of outcrossed individuals increased after several generations, whereas that of selfed individuals remained fairly constant; this was consistent with purging of mildly deleterious recessive alleles. Schoen (1983), Dudash (1990), and Levin (1991) found no differences between one and two consecutive generations of selfing in Gilia angustifolia, Sabatia angularis, and Phlox drummondii, respectively. In contrast, fitness declines over consecutive generations ofinbreeding have been found in maize (Hallauer and Sears 1973), rapeseed (Schuster and Michael 1976), faba beans (Monti and Frusciante 1984), Drosophila (Hollingsworth and Maynard Smith 1955), and Hydrophyllum appendiculatum (Wolfe 1993).…”

Section: Waller Unpubl Data)mentioning

confidence: 87%

THE RELATIONSHIP BETWEEN INBREEDING DEPRESSION AND PRIOR INBREEDING AMONG POPULATIONS OF FOURMIMULUSTAXA

Latta

Ritland

1994

Evolution

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Abstract.-When recessive mutations are the primary cause of inbreeding depression, a negative relationship betweenthe levelsof prior inbreeding and inbreeding depression is expected. We tested this prediction using 15 populations chosen a priori to represent a wide range of prior inbreeding among four closely related taxa of the Mimulus guttatus species complex. Artificially selfed and outcrossed progeny were grown under controlled growth-chamber conditions, and inbreeding depression was estimated for each population as one minus the ratio of the fitness of selfed to outcrossed progeny.Estimates ofinbreeding depression varied from 0%to 68%among populations. Inbreeding coefficients, estimated from electrophoretic assay of field-collected progenies, ranged from 0.02 to 0.76. All five fitness traits displayed a negative association between inbreeding depression and the inbreeding coefficient, but only height showed a statistically significantcorrelation. Inbreedingdepression was also not correlated with the level ofgeneticvariability. In addition, populations with similar levels of prior inbreeding showed significant differences of inbreeding depression, whereaspopulations with differentlevels of prior inbreeding showed similar inbreeding depression. Within populations, inbreeding depression did not differ between progeny selfed one versus two generations. Our results are weakly consistent with the recessive mutation model of inbreeding depression, but suggest that additional factors, including genotype-by-environment interaction and complex modes of inheritance, may influence the expression of inbreeding depression.

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“…Reduced genetic variability may be responsible for a reduction of fitness parameters such as fertility in plants. For example, loss of genetic variability may result in low seed set as familial breeding increases (or mating between related individuals) causing inbreeding depression (Ledig 1986;Levin 1991). However, high levels of heterozygosity have also been suggested to reduce seed set as deleterious recessive lethals accumulate in large numbers in the heterozygous state (segregational load) (Wiens et al 1987;Charlesworth 1989).…”

Section: Introductionmentioning

confidence: 99%

Reproductive success and genetic divergence among varieties of the rare and endangered Astragalus cremnophylax (Fabaceae) from Arizona, USA

2005

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Populations of Astragalus cremnophylax from Arizona and related A. humillimus from New Mexico were assessed for morphological, reproductive, genetic, and ecological differences. Results suggest that some of the taxa (i.e., A. cremnophylax var. cremnophylax and A. humillimus) are poor reproducers and environmental fluctuation is not likely a factor contributing to low fecundity in these species. Astragalus cremnophylax var. cremnophylax appears to have low fecundity due to inbreeding depression. Allozyme data from 18 loci show little within-population and taxon genetic variability. Most genetic variability is distributed among populations and taxa. The population of A. cremnophylax var. cremnophylax from the Grand Canyon (South Rim) was genetically depauperate, indicative of the bottleneck caused by historic trampling at this viewpoint. Cape Final, a population of A. cremnophylax var. cremnophylax on the Grand Canyon (North Rim) is genetically different from typical materials of this taxon (South Rim) and is more closely related to other taxa within this species complex. However, the other varieties of A. cremnophylax are more closely related to A. humillimus than the population at Cape Final, suggesting potential species status for Cape Final materials based on allozyme divergence.

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The Effect of Inbreeding on Seed Survivorship in Phlox

Cited by 15 publications

References 7 publications

Partial self-fertilization and inbreeding depression in two populations of Mimulus guttatus

Partial self-fertilization and inbreeding depression in two populations of Mimulus guttatus

THE RELATIONSHIP BETWEEN INBREEDING DEPRESSION AND PRIOR INBREEDING AMONG POPULATIONS OF FOURMIMULUSTAXA

Reproductive success and genetic divergence among varieties of the rare and endangered Astragalus cremnophylax (Fabaceae) from Arizona, USA

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