Abstract
Inbreeding depression is a major selective force favoring outcrossing in flowering plants. However, some self-fertilization should weaken the harmful effects of inbreeding by exposing deleterious alleles to selection. This study examines the maintenance of inbreeding depression in the predominantly outcrossing species Pinus sylvestris L. (Scots pine). Open-pollinated and self-fertilized progeny of 23 maternal trees, originating from a natural stand in southern Finland, were grown at two sites. We observed significant inbreeding depression in two of the four life stages measured. Inbreeding depression was largest for seed maturation (δ = 0.74), where seedset in open-pollinated strobili (70.9%) was about four times higher than in selfed strobili (18.3%). Inbreeding depression in postgermination survival (upto an age of 23 years) was also high (δ = 0.62-0.75). No significant differences in height (δ = 0.05) or flowering (δ = 0.14) of the trees after 23 years were observed. Cumulative inbreeding depression was high (δ = 0.90-0.94) and differed significantly among maternal families (range 0.45-1.00). The magnitude of inbreeding depression among the 23 maternal parents was not significantly correlated between early (seed maturation) and later (postgermination survival) life stages, suggesting that its genetic basis varies across the life cycle. Size differences among the progeny types diminished in time due to nonrandom size-specific mortality, causing a decrease in the inbreeding depression estimates for height over time. Our results indicate that Scots pine exhibits high levels of inbreeding depression during both early and later stages of the life cycle. It is argued that self-fertilization in Scots pine is inefficient in purging the genetic load caused by highly deleterious mutations because of the nearly complete loss of selfed individuals over time. This results in an effectively random mating outcrossing population.
Abstract from the paper’s OpenAlex record, shown for indexing and research. Copyright remains with the authors or the publisher. Read at the source ↗
The text the model read, with the source record’s inline markup (italics, sub- and superscripts) rendered and its character entities decoded; quote offsets refer to the raw text.
Claims 11
Claim · model-written summary
Selfing reduced seed maturation relative to open pollination.
- Taxon
- SCOTS PINE
Pinus sylvestrist0 - Treatment
- selfed strobilie0
- Outcome
- seedsete0
- Direction
- highere0
- Value
- δ = 0.74e0
- Qualifier
- 70.9%e0
- Comparator
- open-pollinated strobilie0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Inbreeding depression was largest for seed maturation (δ = 0.74), where seedset in open-pollinated strobili (70.9%) was about four times higher than in selfed strobili (18.3%).”
t0“SCOTS PINE”
Claim · model-written summary
Selfed progeny had high postgermination survival depression through age 23.
- Taxon
- SCOTS PINEPinus sylvestrist0
- Outcome
- postgermination survivale0
- Direction
- highe0
- Value
- δ = 0.62-0.75e0
- Qualifier
- upto an age of 23 yearse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Inbreeding depression in postgermination survival (upto an age of 23 years) was also high (δ = 0.62-0.75).”
t0“SCOTS PINE”
Claim · model-written summary
Height after 23 years did not differ significantly by progeny type.
- Taxon
- SCOTS PINEPinus sylvestrist0
- Outcome
- heighte0
- Direction
- No significant differencese0
- Value
- δ = 0.05e0
- Qualifier
- after 23 yearse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“No significant differences in height (δ = 0.05) or flowering (δ = 0.14) of the trees after 23 years were observed.”
t0“SCOTS PINE”
Claim · model-written summary
Flowering after 23 years did not differ significantly by progeny type.
- Taxon
- SCOTS PINEPinus sylvestrist0
- Outcome
- floweringe0
- Direction
- No significant differencese0
- Value
- δ = 0.14e0
- Qualifier
- after 23 yearse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“No significant differences in height (δ = 0.05) or flowering (δ = 0.14) of the trees after 23 years were observed.”
t0“SCOTS PINE”
Claim · model-written summary
Cumulative inbreeding depression was high.
- Taxon
- SCOTS PINEPinus sylvestrist0
- Outcome
- Cumulative inbreeding depressione0
- Direction
- highe0
- Value
- δ = 0.90-0.94e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Cumulative inbreeding depression was high (δ = 0.90-0.94) and differed significantly among maternal families (range 0.45-1.00).”
t0“SCOTS PINE”
Claim · model-written summary
Cumulative inbreeding depression varied significantly among maternal families.
- Taxon
- SCOTS PINEPinus sylvestrist0
- Material
- maternal familiese0
- Outcome
- Cumulative inbreeding depressione0
- Direction
- differede0
- Value
- range 0.45-1.00e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Cumulative inbreeding depression was high (δ = 0.90-0.94) and differed significantly among maternal families (range 0.45-1.00).”
t0“SCOTS PINE”
Claim · model-written summary
Early and later inbreeding depression were not significantly correlated among maternal parents.
- Taxon
- SCOTS PINEPinus sylvestrist0
- Organ / stage
- seed maturatione0
- Outcome
- magnitude of inbreeding depressione0
- Direction
- not significantly correlatede0
- Comparator
- postgermination survivale0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The magnitude of inbreeding depression among the 23 maternal parents was not significantly correlated between early (seed maturation) and later (postgermination survival) life stages”
t0“SCOTS PINE”
Claim · model-written summary
Progeny size differences diminished over time.
- Taxon
- SCOTS PINEPinus sylvestrist0
- Outcome
- Size differencese0
- Direction
- diminishede0
- Qualifier
- nonrandom size-specific mortalitye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Size differences among the progeny types diminished in time due to nonrandom size-specific mortality, causing a decrease in the inbreeding depression estimates for height over time.”
t0“SCOTS PINE”
Claim · model-written summary
Height inbreeding depression estimates decreased over time.
- Taxon
- SCOTS PINEPinus sylvestrist0
- Outcome
- inbreeding depression estimates for heighte0
- Direction
- decreasee0
- Qualifier
- nonrandom size-specific mortalitye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Size differences among the progeny types diminished in time due to nonrandom size-specific mortality, causing a decrease in the inbreeding depression estimates for height over time.”
t0“SCOTS PINE”
Claim · model-written summary
Authors argue that self-fertilization inefficiently purges genetic load in Scots pine because selfed individuals are nearly entirely lost.
- Taxon
- Scots pinePinus sylvestrise0
- Outcome
- inefficient in purging the genetic loade0
- Qualifier
- nearly complete loss of selfed individuals over timee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“It is argued that self-fertilization in Scots pine is inefficient in purging the genetic load caused by highly deleterious mutations because of the nearly complete loss of selfed individuals over time.”
Claim · model-written summary
Authors infer that the population is effectively randomly mating and outcrossing.
- Taxon
- SCOTS PINEPinus sylvestrist0
- Outcome
- effectively random mating outcrossing populatione0
- Qualifier
- effectively random matinge0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“This results in an effectively random mating outcrossing population.”
t0“SCOTS PINE”