Abstract
Defoliation during reproductive growth of soybean [ Glycine max (L.) Merr.] may significantly reduce yields. The objective of this study was to elucidate the relationships among organism‐induced defoliation, CO 2 exchange rates, and reproductive growth in fieldgrown soybean. Soybean (‘Bragg’) plots were sprayed a factorial design with diflubenzuron (0.035 kg a.i./ha) and a benomyl‐maneb mixture (1.12 a.i./ha) on two dates, first at early flowering (5 August) and again at early pod set (19 August). Diflubenzuron application prevented defoliation by velvetbean caterpillar ( Anticarsia gemmatalis Hubner). By 12 September, LAI was reduced from 5.5 to 2.8, leaf dry weight from 185 to 110 g/m 2 , and midday light interception from 94 to 72% in defoliated as compared to non‐defoliated plots. While canopy specific leaf weight (SLW) increased in all treatments during the experimental period, SLW was 1.0 mg/cm 2 higher in defoliated than non‐defoliated plots. On 4 September defoliated plots were sprayed with diflubenzuron (0.035 kg a.i./ha) and carbaryl (0.56 kg a.i./ha) prevent further leaf loss. Canopy CO 2 exchange was measured at various photosynthetic photon flux densities (PPFD) to develop photosynthesis light response curves. Net canopy photosynthesis at 1,500 μE·m −2 ·sec −1 PPFD (PN1500) declined steadily in all treatments during seed growth. PN1500 and plant dark respiration, respectively, were reduced by 6.8 and 3.3 mg CO 2 ·dm −2 ·hour −1 in defoliated compared to non‐defoliated plots. Soil CO 2 efflux rates did not differ significantly (P < 0.05) between treatments. Differences in pod growth rates (7.6 and 9.21 g·m −2 ·day −1 and yields (434 and 502 g·m −2 ) between defoliated and non‐defoliated plots, respectively, were attributed to differences in canopy photosynthetic capacity. There was no apparent effect of defoliation on seed growth duration or seed abortion. Rather, yield reduction in defoliated plots was related primarily to slowing of the individual seed growth rate. Balance of carbon flux to seeds showed relationships between instantaneous canopy CO 2 exchange measurements and sequential harvest data.
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Claims 12
Claim · model-written summary
Diflubenzuron prevented defoliation of soybean by velvetbean caterpillar.
- Taxon
- Glycine max
Glycine maxe0 - Treatment
- Diflubenzuron applicatione1
- Interactor
- Anticarsia gemmatalis
Anticarsia gemmatalise1pest - Outcome
- defoliatione1
- Direction
- preventede1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“soybean [ Glycine max (L.) Merr.]”
e1“Diflubenzuron application prevented defoliation by velvetbean caterpillar ( Anticarsia gemmatalis Hubner)”
Claim · model-written summary
Defoliation reduced soybean leaf area index from 5.5 to 2.8 by 12 September.
- Taxon
- Glycine maxGlycine maxe0
- Treatment
- defoliatede3
- Outcome
- LAIe2
- Direction
- reducede2
- Value
- 5.5 to 2.8e2
- Comparator
- non‐defoliated plotse3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“soybean [ Glycine max (L.) Merr.]”
e2“LAI was reduced from 5.5 to 2.8, leaf dry weight from 185 to 110 g/m 2 , and midday light interception from 94 to 72%”
e3“in defoliated as compared to non‐defoliated plots”
Claim · model-written summary
Defoliation reduced soybean leaf dry weight from 185 to 110 g/m2.
- Taxon
- Glycine maxGlycine maxe0
- Treatment
- defoliatede3
- Outcome
- leaf dry weighte2
- Direction
- reducede2
- Value
- 185 to 110e2
- Comparator
- non‐defoliated plotse3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“soybean [ Glycine max (L.) Merr.]”
e2“LAI was reduced from 5.5 to 2.8, leaf dry weight from 185 to 110 g/m 2 , and midday light interception from 94 to 72%”
e3“in defoliated as compared to non‐defoliated plots”
Claim · model-written summary
Defoliation reduced midday light interception in soybean from 94 to 72%.
- Taxon
- Glycine maxGlycine maxe0
- Treatment
- defoliatede3
- Outcome
- midday light interceptione2
- Direction
- reducede2
- Value
- 94 to 72%e2
- Comparator
- non‐defoliated plotse3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“soybean [ Glycine max (L.) Merr.]”
e2“LAI was reduced from 5.5 to 2.8, leaf dry weight from 185 to 110 g/m 2 , and midday light interception from 94 to 72%”
e3“in defoliated as compared to non‐defoliated plots”
Claim · model-written summary
Net canopy photosynthesis declined steadily in all treatments during seed growth.
- Taxon
- Glycine maxGlycine maxe0
- Organ / stage
- seed growthe6
- Outcome
- Net canopy photosynthesise5
- Direction
- declined steadilye6
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“soybean [ Glycine max (L.) Merr.]”
e5“Net canopy photosynthesis”
e6“declined steadily in all treatments during seed growth”
Claim · model-written summary
Defoliation reduced PN1500 canopy photosynthesis by 6.8 mg CO2 per dm2 per hour.
- Taxon
- Glycine maxGlycine maxe0
- Treatment
- defoliatede1
- Outcome
- PN1500e2
- Direction
- reducede7
- Value
- 6.8e7
- Comparator
- non‐defoliated plotse1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“soybean [ Glycine max (L.) Merr.]”
e7“were reduced by 6.8 and 3.3”
e1“in defoliated compared to non‐defoliated plots”
e2“PN1500 and plant dark respiration, respectively”
Claim · model-written summary
Defoliation reduced plant dark respiration by 3.3 mg CO2 per dm2 per hour.
- Taxon
- Glycine maxGlycine maxe0
- Treatment
- defoliatede1
- Outcome
- plant dark respiratione2
- Direction
- reducede7
- Value
- 3.3e7
- Comparator
- non‐defoliated plotse1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“soybean [ Glycine max (L.) Merr.]”
e7“were reduced by 6.8 and 3.3”
e1“in defoliated compared to non‐defoliated plots”
e2“PN1500 and plant dark respiration, respectively”
Claim · model-written summary
Pod growth rates differed between defoliated and non-defoliated soybean plots (7.6 and 9.21).
- Taxon
- Glycine maxGlycine maxe0
- Outcome
- pod growth ratese1
- Value
- 7.6 and 9.21e1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“soybean [ Glycine max (L.) Merr.]”
e1“Differences in pod growth rates (7.6 and 9.21”
Claim · model-written summary
Soybean yields in defoliated and non-defoliated plots were 434 and 502 g/m2.
- Taxon
- Glycine maxGlycine maxe0
- Outcome
- yieldse1
- Value
- 434 and 502e1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“soybean [ Glycine max (L.) Merr.]”
e1“yields (434 and 502”
Claim · model-written summary
Defoliation had no apparent effect on seed growth duration or seed abortion in soybean.
- Taxon
- Glycine maxGlycine maxe0
- Treatment
- defoliatione1
- Outcome
- seed growth duration or seed abortione1
- Direction
- no apparent effecte1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“soybean [ Glycine max (L.) Merr.]”
e1“There was no apparent effect of defoliation on seed growth duration or seed abortion”
Claim · model-written summary
Yield reduction in defoliated plots was related primarily to slowing of individual seed growth rate.
- Taxon
- Glycine maxGlycine maxe0
- Treatment
- defoliated plotse1
- Outcome
- individual seed growth ratee1
- Direction
- slowinge1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“soybean [ Glycine max (L.) Merr.]”
e1“yield reduction in defoliated plots was related primarily to slowing of the individual seed growth rate”
Claim · model-written summary
Carbon flux to seeds showed relationships between instantaneous canopy CO2 exchange and sequential harvest data.
Verbatim
e1“Balance of carbon flux to seeds showed relationships between instantaneous canopy CO 2 exchange measurements and sequential harvest data”
The same questions in other papers
pruning · physiology: photosynthesis · Glycine max (soybean)Results differ
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1 paper in the same direction as this paper
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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.