Abstract
SUMMARY A substantial loss in yield usually occurs when oilseed rape is sown later than mid-September. Field experiments in 1972–3 tested whether this is because all plants, irrespective of size, initiate inflorescences during the winter, thus restricting the eventual size of the leaf canopy and the yield potential of late-sown plants, which are still very small when the change to the reproductive phase occurs. Sowing a standard winter variety, Victor, from mid-August to mid-October resulted in initiation occurring from late October to February. When sown after mid-September yields were proportional to plant size at initiation. The winter was mild, and in colder conditions earlier sowing may be required to enable plants to reach a critical size before initiation takes place. When sown in August plants were very large but yield was not improved. A study of the development of the pod canopy showed that the extra yield potential was not realized because heavy losses of pods and seeds occurred, particularly in the more shaded positions. When a range of winter varieties, chosen to contrast the timing of phasic development, was sown on two dates yield was proportional to the interval between sowing and initiation, particularly when late sown, presumably because late initiators were able to lay the foundation of a more substantial root and shoot system. This has implications for plant breeding programmes because the low erucic acid varieties currently being grown initiate inflorescences early. When spring types were sown in mid-October they formed floral initials very early, and gave particularly small and weak plants, with a low yield. Winter types sown in March did initiate flowers and produce large plants, but yields were no better than spring types as flowering and ripening were irregular and late, the cold requirement for initiation being only marginally fulfilled.
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Claims 12
Claim · model-written summary
Victor sown mid-August to mid-October initiated from late October to February.
- Taxon
- oilseed rape
_Brassica_napus_-_Habit.jpg?width=60)
Brassica napust0 - Material
- Victore0
- Treatment
- mid-August to mid-Octobere0
- Outcome
- initiation occurring from late October to Februarye0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
_Brassica_napus_-_Habit.jpg?width=500)
Verbatim
e0“Sowing a standard winter variety, Victor, from mid-August to mid-October resulted in initiation occurring from late October to February”
t0“oilseed rape”
Claim · model-written summary
For sowing after mid-September, yield was proportional to size at initiation.
- Taxon
- oilseed rapeBrassica napust0
- Organ / stage
- plant size at initiatione0
- Outcome
- yieldse0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“When sown after mid-September yields were proportional to plant size at initiation”
t0“oilseed rape”
Claim · model-written summary
August sowing produced very large plants.
- Taxon
- oilseed rapeBrassica napust0
- Outcome
- plants were very largee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“When sown in August plants were very large”
t0“oilseed rape”
Claim · model-written summary
August sowing did not improve yield.
- Taxon
- oilseed rapeBrassica napust0
- Treatment
- sown in Auguste0
- Outcome
- yielde0
- Direction
- not improvede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“When sown in August plants were very large but yield was not improved”
t0“oilseed rape”
Claim · model-written summary
Heavy losses of pods and seeds occurred, especially in shade.
- Taxon
- oilseed rapeBrassica napust0
- Outcome
- heavy losses of pods and seedse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“heavy losses of pods and seeds occurred, particularly in the more shaded positions”
t0“oilseed rape”
Claim · model-written summary
Winter-variety yield was proportional to the interval from sowing to initiation.
- Taxon
- oilseed rapeBrassica napust0
- Organ / stage
- interval between sowing and initiatione0
- Outcome
- yielde0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“yield was proportional to the interval between sowing and initiation, particularly when late sown”
t0“oilseed rape”
Claim · model-written summary
Mid-October spring types formed floral initials very early.
- Taxon
- oilseed rapeBrassica napust0
- Material
- spring typese0
- Outcome
- formed floral initials very earlye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“When spring types were sown in mid-October they formed floral initials very early”
t0“oilseed rape”
Claim · model-written summary
Mid-October spring types produced particularly small and weak plants.
- Taxon
- oilseed rapeBrassica napust0
- Material
- spring typese0
- Outcome
- particularly small and weak plantse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“When spring types were sown in mid-October they formed floral initials very early, and gave particularly small and weak plants”
t0“oilseed rape”
Claim · model-written summary
Mid-October spring types had low yield.
- Taxon
- oilseed rapeBrassica napust0
- Material
- spring typese0
- Outcome
- low yielde0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“When spring types were sown in mid-October they formed floral initials very early, and gave particularly small and weak plants, with a low yield”
t0“oilseed rape”
Claim · model-written summary
March-sown winter types initiated flowers and became large.
- Taxon
- oilseed rapeBrassica napust0
- Material
- Winter typese0
- Outcome
- initiate flowers and produce large plantse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Winter types sown in March did initiate flowers and produce large plants”
t0“oilseed rape”
Claim · model-written summary
March-sown winter types yielded no better than spring types.
- Taxon
- oilseed rapeBrassica napust0
- Treatment
- Winter types sown in Marche0
- Outcome
- yieldse0
- Direction
- no bettere0
- Comparator
- spring typese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Winter types sown in March did initiate flowers and produce large plants, but yields were no better than spring types”
t0“oilseed rape”
Claim · model-written summary
March-sown winter types flowered and ripened irregularly and late.
- Taxon
- oilseed rapeBrassica napust0
- Outcome
- flowering and ripening were irregular and latee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“flowering and ripening were irregular and late”
t0“oilseed rape”
The same questions in other papers
sowing time · yield · Brassica napus (oilseed rape)Positive and negative results
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See all 71 papers →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.