Abstract
SUMMARY Three wheat experiments are described in which a range of plant populations were shaded during different periods of development; in two of the experiments plant thinning was also carried out at a number of growth stages. Shading during the period of ear development caused an appreciable decrease in grain yield by decreasing the number of grains per ear. Shading during the grain filling period also reduced grain yield, this being brought about by decreased grain size. Thus in contrast to the barley experiments reported earlier (Willey & Holhday, 1971), these particular results gave no indication of a potential surplus of carbohydrate for grain filling and an associated limited ear capacity. However, when plant thinning was carried out at anthesis to make more carbohydrate available for grain filling in the remaining ears, grain yield per ear did not increase. It is argued, therefore, that grain yield probably was determined at least partly by a limited ear capacity. Plant thinning at earlier stages showed how the development of competition during the ear development period progressively reduced the potential capacity of the ear; the greater competition of higher plant populations accelerated this reduction in ear potential. From an examination of the effects of plant population, it is suggested that the number of grains per ear is the component having greatest influence on the decline in grain yield at above-optimum populations. The possible importance of the number of grains per unit area as an indicator of ear capacity on an area basis, and as a determinant of grain yield per unit area, is emphasized. A close relationship between grain yield per unit area and number of grains per unit area is illustrated for a number of plant-population response curves, and it is suggested that the decrease in grain yield at high populations is probably determined by a decrease in the number of grains per unit area. Evidence is presented to substantiate the idea put forward in the barley paper that this decrease in the number of grains per unit area may be attributable more to a lower production of total dry matter by the high populations during the later stages of ear development, than to an unfavourable partitioning of such dry matter between the ear and the rest of the plant.
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Claims 11
Claim · model-written summary
Shading during ear development decreased wheat grain yield.
- Taxon
- wheat
Triticum aestivumt0 - Treatment
- Shading during the period of ear developmente0
- Outcome
- grain yielde0
- Direction
- decreasee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Shading during the period of ear development caused an appreciable decrease in grain yield”
t0“wheat”
Claim · model-written summary
Ear development shading decreased grains per ear.
- Taxon
- wheatTriticum aestivumt0
- Treatment
- Shading during the period of ear developmente1
- Outcome
- number of grains per eare0
- Direction
- decreasinge0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“by decreasing the number of grains per ear.”
t0“wheat”
e1“Shading during the period of ear development caused an appreciable decrease in grain yield”
Claim · model-written summary
Grain filling shading reduced grain yield.
- Taxon
- wheatTriticum aestivumt0
- Treatment
- Shading during the grain filling periode0
- Outcome
- grain yielde0
- Direction
- reducede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Shading during the grain filling period also reduced grain yield”
t0“wheat”
Claim · model-written summary
Grain filling shading decreased grain size.
- Taxon
- wheatTriticum aestivumt0
- Treatment
- Shading during the grain filling periode1
- Outcome
- grain sizee0
- Direction
- decreasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“this being brought about by decreased grain size.”
t0“wheat”
e1“Shading during the grain filling period also reduced grain yield”
Claim · model-written summary
Thinning at anthesis did not increase yield per remaining ear.
- Taxon
- wheatTriticum aestivumt0
- Treatment
- plant thinning was carried out at anthesise0
- Outcome
- grain yield per eare0
- Direction
- did not increasee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“when plant thinning was carried out at anthesis to make more carbohydrate available for grain filling in the remaining ears, grain yield per ear did not increase.”
t0“wheat”
Claim · model-written summary
Earlier thinning showed competition progressively reduced ear capacity.
- Taxon
- wheatTriticum aestivumt0
- Outcome
- potential capacity of the eare0
- Direction
- reducede0
- Qualifier
- competition during the ear development periode0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Plant thinning at earlier stages showed how the development of competition during the ear development period progressively reduced the potential capacity of the ear”
t0“wheat”
Claim · model-written summary
Higher population competition accelerated reduction in ear potential.
- Taxon
- wheatTriticum aestivumt0
- Outcome
- ear potentiale0
- Direction
- reductione0
- Setting
- higher plant populationse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the greater competition of higher plant populations accelerated this reduction in ear potential.”
t0“wheat”
Claim · model-written summary
Grains per ear were suggested to most influence yield decline above optimum population.
- Taxon
- wheatTriticum aestivumt0
- Organ / stage
- eare0
- Outcome
- grain yielde0
- Direction
- declinee0
- Qualifier
- above-optimum populationse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the number of grains per ear is the component having greatest influence on the decline in grain yield at above-optimum populations.”
t0“wheat”
Claim · model-written summary
Grain yield per area closely related to grains per area across population response curves.
- Taxon
- wheatTriticum aestivumt0
- Outcome
- grain yield per unit areae0
- Setting
- plant-population response curvese0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“A close relationship between grain yield per unit area and number of grains per unit area is illustrated for a number of plant-population response curves”
t0“wheat”
Claim · model-written summary
High population yield decline was suggested to result from fewer grains per area.
- Taxon
- wheatTriticum aestivumt0
- Outcome
- decrease in grain yielde0
- Qualifier
- decrease in the number of grains per unit areae0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the decrease in grain yield at high populations is probably determined by a decrease in the number of grains per unit area.”
t0“wheat”
Claim · model-written summary
Fewer grains per area at high density were attributed more to reduced late dry matter production than unfavorable partitioning.
- Taxon
- wheatTriticum aestivumt0
- Outcome
- decrease in the number of grains per unit areae0
- Qualifier
- lower production of total dry mattere0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“this decrease in the number of grains per unit area may be attributable more to a lower production of total dry matter by the high populations during the later stages of ear development, than to an unfavourable partitioning of such dry matter between the ear and the rest of the plant.”
t0“wheat”
The same questions in other papers
shade · yield · Triticum aestivum (wheat)Positive and negative results
59 papers in the same direction as this paper · 9 in the opposite direction
- negative
- negative
- no effect
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See all 69 papers →pruning · yield · Triticum aestivum (wheat)Positive and negative results
59 papers in the same direction as this paper · 33 in the opposite direction
- positive
- positive
- positive
89 papers more in this group
See all 93 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.