Abstract
Seed production of red clover (Trifolium pratense L.) largely depends on bumble bees’ pollination. Compared to diploids, the lower seed yield of tetraploids limits the commercial exploitation despite a higher forage yield, persistence and disease resistance. Inadequate pollination was previously suggested as a reason for the low seed yield in tetraploids. However, pollination conditions are complex, making it difficult to compare the pollination between diploid and tetraploid red clover. This study aimed to evaluate pollination and reproductive success in red clover using three pollination approaches: hand pollination, honey bee and bumble bee pollination. Pollination by hand and honey bees was used to investigate the optimal visitation rate and flowering stage to maximise reproductive success. Diploid and tetraploid red clover cultivars released from different years were used to explore the influence of breeding improvements. Pollinator performance among different bee species visiting diploids and tetraploids was investigated under field conditions. Collectively, the reproductive success between diploids and tetraploids was compared among different pollination approaches. Results showed that pollination conditions were poorly described in previous studies and my review emphasised the importance of linking pollination and reproductive success. With the increase of “visitation rate” in hand pollination, the seed number per floret was reduced. Pollination at the full flowering stage obtained a higher seed number per floret than the early flowering stage. When comparing three pollination approaches, hand pollination in general obtained lower reproductive success than both honey bee and bumble bee pollination, depending on the pollen diversity. Furthermore, these findings emphasise the importance of multiple bee visits in order to maximise reproductive success. Bumble bee species of Bombus hortorum L. and Bombus pascuorum Scopoli were the dominant pollinators during the early flowering stage, whereas the latter was active throughout the flowering season. Stigmatic pollen deposition was found not different among pollinator species or plant ploidy levels. Visit frequency and visitation rate did not vary between the two ploidy levels but among bee species. However, relative abundance differed between diploids and tetraploids, probably related to corolla tube length. Compared to diploids, tetraploids had lower reproductive success in terms of seed set, pollen viability and pollen germination. Reproductive success of tetraploids seems improved with breeding over the past 50 years. This study provides insights towards understanding the role of pollination in red clover reproductive success. Future research perspectives in terms of crop pollination management, pollinator conservation and plant breeding for seed crops were considered. To conclude, tetraploid red clover has lower reproductive success compared to diploid red clover, regardless of pollination approaches.
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Claims 18
Claim · model-written summary
Earlier studies poorly described pollination conditions.
- Outcome
- pollination conditionse0
Not reportedTaxon
Verbatim
e0“pollination conditions were poorly described in previous studies”
Claim · model-written summary
Increasing hand pollination visitation rate reduced seeds per floret.
- Taxon
- red clover
Trifolium pratenset0 - Treatment
- hand pollinatione0
- Outcome
- seed number per florete0
- Direction
- reducede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“With the increase of “visitation rate” in hand pollination, the seed number per floret was reduced.”
t0“Evaluation of pollination and reproductive success in red clover (Trifolium pratense L.)”
Claim · model-written summary
Pollination at full flowering produced more seeds per floret than at early flowering.
- Taxon
- red cloverTrifolium pratenset0
- Treatment
- full flowering stagee0
- Outcome
- seed number per florete0
- Direction
- highere0
- Comparator
- early flowering stagee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Pollination at the full flowering stage obtained a higher seed number per floret than the early flowering stage.”
t0“Evaluation of pollination and reproductive success in red clover (Trifolium pratense L.)”
Claim · model-written summary
Hand pollination generally produced less reproductive success than honey bee pollination, depending on pollen diversity.
- Taxon
- red cloverTrifolium pratenset0
- Treatment
- hand pollinatione0
- Outcome
- reproductive successe0
- Direction
- lowere0
- Qualifier
- depending on the pollen diversitye0
- Comparator
- honey beee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“hand pollination in general obtained lower reproductive success than both honey bee and bumble bee pollination, depending on the pollen diversity.”
t0“Evaluation of pollination and reproductive success in red clover (Trifolium pratense L.)”
Claim · model-written summary
Hand pollination generally produced less reproductive success than bumble bee pollination, depending on pollen diversity.
- Taxon
- red cloverTrifolium pratenset0
- Treatment
- hand pollinatione0
- Outcome
- reproductive successe0
- Direction
- lowere0
- Qualifier
- depending on the pollen diversitye0
- Comparator
- bumble bee pollinatione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“hand pollination in general obtained lower reproductive success than both honey bee and bumble bee pollination, depending on the pollen diversity.”
t0“Evaluation of pollination and reproductive success in red clover (Trifolium pratense L.)”
Claim · model-written summary
The authors emphasize multiple bee visits to maximize reproductive success.
- Taxon
- red cloverTrifolium pratenset0
- Outcome
- multiple bee visitse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“multiple bee visits in order to maximise reproductive success.”
t0“Evaluation of pollination and reproductive success in red clover (Trifolium pratense L.)”
Claim · model-written summary
Bombus hortorum was a dominant pollinator during early flowering.
- Taxon
- red cloverTrifolium pratenset0
- Organ / stage
- early flowering stagee0
- Interactor
- Bombus hortorum L.
Bombus hortorume0pollinator - Outcome
- dominant pollinatorse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Bumble bee species of Bombus hortorum L. and Bombus pascuorum Scopoli were the dominant pollinators during the early flowering stage”
t0“Evaluation of pollination and reproductive success in red clover (Trifolium pratense L.)”
Claim · model-written summary
Bombus pascuorum was a dominant pollinator during early flowering.
- Taxon
- red cloverTrifolium pratenset0
- Organ / stage
- early flowering stagee0
- Interactor
- Bombus pascuorum Scopoli
_-_Medicago_x_varia_-_Keila.jpg?width=60)
Bombus pascuorume0pollinator - Outcome
- dominant pollinatorse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
_-_Medicago_x_varia_-_Keila.jpg?width=500)
Verbatim
e0“Bumble bee species of Bombus hortorum L. and Bombus pascuorum Scopoli were the dominant pollinators during the early flowering stage”
t0“Evaluation of pollination and reproductive success in red clover (Trifolium pratense L.)”
Claim · model-written summary
Bombus pascuorum remained active throughout flowering.
- Taxon
- red cloverTrifolium pratenset0
- Interactor
- Bombus pascuorum ScopoliBombus pascuorumt1pollinator
- Outcome
- active throughout the flowering seasone0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the latter was active throughout the flowering season.”
t0“Evaluation of pollination and reproductive success in red clover (Trifolium pratense L.)”
t1“Bumble bee species of Bombus hortorum L. and Bombus pascuorum Scopoli were the dominant pollinators during the early flowering stage”
Claim · model-written summary
Stigmatic pollen deposition did not differ among pollinator species.
- Taxon
- red cloverTrifolium pratenset0
- Outcome
- Stigmatic pollen depositione0
- Direction
- not differente0
- Comparator
- pollinator speciese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Stigmatic pollen deposition was found not different among pollinator species or plant ploidy levels.”
t0“Evaluation of pollination and reproductive success in red clover (Trifolium pratense L.)”
Claim · model-written summary
Stigmatic pollen deposition did not differ between ploidy levels.
- Taxon
- red cloverTrifolium pratenset0
- Outcome
- Stigmatic pollen depositione0
- Direction
- not differente0
- Comparator
- plant ploidy levelse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Stigmatic pollen deposition was found not different among pollinator species or plant ploidy levels.”
t0“Evaluation of pollination and reproductive success in red clover (Trifolium pratense L.)”
Claim · model-written summary
Visit frequency and visitation rate did not vary between ploidy levels.
- Taxon
- red cloverTrifolium pratenset0
- Outcome
- Visit frequency and visitation ratee0
- Direction
- did not varye0
- Comparator
- two ploidy levelse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Visit frequency and visitation rate did not vary between the two ploidy levels but among bee species.”
t0“Evaluation of pollination and reproductive success in red clover (Trifolium pratense L.)”
Claim · model-written summary
Visit frequency and visitation rate varied among bee species.
- Taxon
- red cloverTrifolium pratenset0
- Outcome
- Visit frequency and visitation ratee0
- Comparator
- bee speciese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Visit frequency and visitation rate did not vary between the two ploidy levels but among bee species.”
t0“Evaluation of pollination and reproductive success in red clover (Trifolium pratense L.)”
Claim · model-written summary
Pollinator relative abundance differed between diploid and tetraploid clover.
- Taxon
- red cloverTrifolium pratenset0
- Outcome
- relative abundancee0
- Direction
- differede0
- Comparator
- diploids and tetraploidse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“relative abundance differed between diploids and tetraploids, probably related to corolla tube length.”
t0“Evaluation of pollination and reproductive success in red clover (Trifolium pratense L.)”
Claim · model-written summary
Tetraploids had lower seed set than diploids.
- Taxon
- red cloverTrifolium pratenset0
- Material
- tetraploidse0
- Outcome
- seed sete0
- Direction
- lowere0
- Comparator
- diploidse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Compared to diploids, tetraploids had lower reproductive success in terms of seed set, pollen viability and pollen germination.”
t0“Evaluation of pollination and reproductive success in red clover (Trifolium pratense L.)”
Claim · model-written summary
Tetraploids had lower pollen viability than diploids.
- Taxon
- red cloverTrifolium pratenset0
- Material
- tetraploidse0
- Outcome
- pollen viabilitye0
- Direction
- lowere0
- Comparator
- diploidse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Compared to diploids, tetraploids had lower reproductive success in terms of seed set, pollen viability and pollen germination.”
t0“Evaluation of pollination and reproductive success in red clover (Trifolium pratense L.)”
Claim · model-written summary
Tetraploids had lower pollen germination than diploids.
- Taxon
- red cloverTrifolium pratenset0
- Material
- tetraploidse0
- Outcome
- pollen germinatione0
- Direction
- lowere0
- Comparator
- diploidse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Compared to diploids, tetraploids had lower reproductive success in terms of seed set, pollen viability and pollen germination.”
t0“Evaluation of pollination and reproductive success in red clover (Trifolium pratense L.)”
Claim · model-written summary
Tetraploid reproductive success appears to have improved over 50 years of breeding.
- Taxon
- red cloverTrifolium pratenset0
- Material
- tetraploidse0
- Outcome
- Reproductive successe0
- Direction
- improvede0
- Qualifier
- over the past 50 yearse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Reproductive success of tetraploids seems improved with breeding over the past 50 years.”
t0“Evaluation of pollination and reproductive success in red clover (Trifolium pratense L.)”
The same questions in other papers
stage · yield · Trifolium pratense (red clover)Results agree
2 papers in the same direction as this paper
- positive
- positive
Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.