Abstract
Quantifying the effect of leaf area loss on sunflower ( Helianthus annuus L.) yield caused by hail, pests, and diseases is important in the management of this crop, both from a technical and economic point of view. The effect of defoliation depends, however, on the foliar surface eliminated and on the growth stage at which this takes place. This effect has been quantified in the USA, but these data are lacking for specific conditions of Europe. The aim of this paper was to determine the response of sunflower cultivation to several levels of defoliation that took place at different growth stages under European growth conditions. Four field trials were conducted by applying four defoliation treatments (nondefoliated control, 33, 66, and 100%) at different growth stages ranging from preflowering (R2) to physiological maturity (R9). Crop yield loss increased with increasing level of defoliation. Preflowering stage R3 was the most sensitive. At this stage a 100% defoliation of the leaf surface resulted in 92% yield loss, reducing both the number of seeds per head and 1000‐seed weight. A 100% defoliation at stage R7 (back of head a pale yellow) caused a 50% yield loss, while at stage R9 (physiological maturity) defoliation had no effect on yield. The yield loss caused by defoliation at different plant growth stages under European conditions differed slightly from the one designed for U.S. conditions.
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Claims 7
Claim · model-written summary
Sunflower yield loss increased as defoliation increased.
- Taxon
- Sunflower
Helianthus annuust0 - Treatment
- defoliatione0
- Outcome
- Crop yield losse0
- Direction
- increasede0
- Comparator
- increasing level of defoliatione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Crop yield loss increased with increasing level of defoliation.”
t0“Sunflower”
Claim · model-written summary
The R3 preflowering stage was most sensitive to defoliation.
- Taxon
- SunflowerHelianthus annuust0
- Organ / stage
- Preflowering stage R3e0
- Outcome
- most sensitivee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Preflowering stage R3 was the most sensitive.”
t0“Sunflower”
Claim · model-written summary
At R3, complete defoliation caused 92% yield loss.
- Taxon
- SunflowerHelianthus annuust0
- Organ / stage
- this stagee0
- Treatment
- 100% defoliation of the leaf surfacee0
- Outcome
- yield losse0
- Direction
- losse0
- Value
- 92%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“At this stage a 100% defoliation of the leaf surface resulted in 92% yield loss”
t0“Sunflower”
Claim · model-written summary
At R3, complete defoliation reduced seeds per head and seed weight.
- Taxon
- SunflowerHelianthus annuust0e1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“reducing both the number of seeds per head and 1000‐seed weight”
t0“Sunflower”
e1“At this stage a 100% defoliation of the leaf surface resulted in 92% yield loss”
Claim · model-written summary
At R7, complete defoliation caused 50% yield loss.
- Taxon
- SunflowerHelianthus annuust0
- Organ / stage
- stage R7e0
- Treatment
- 100% defoliatione0
- Outcome
- yield losse0
- Direction
- losse0
- Value
- 50%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“A 100% defoliation at stage R7 (back of head a pale yellow) caused a 50% yield loss”
t0“Sunflower”
Claim · model-written summary
At R9, defoliation had no effect on yield.
- Taxon
- SunflowerHelianthus annuust0
- Organ / stage
- stage R9e0
- Treatment
- defoliatione0
- Outcome
- yielde0
- Direction
- no effecte0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“at stage R9 (physiological maturity) defoliation had no effect on yield”
t0“Sunflower”
Claim · model-written summary
Yield loss under European conditions differed slightly from the US schedule.
- Taxon
- SunflowerHelianthus annuust0
- Outcome
- yield losse0
- Direction
- differed slightlye0
- Comparator
- the one designed for U.S. conditionse0
- Setting
- European conditionse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The yield loss caused by defoliation at different plant growth stages under European conditions differed slightly from the one designed for U.S. conditions.”
t0“Sunflower”
The same questions in other papers
pruning · yield · Helianthus annuus (common sunflower)Results differ
6 papers in the same direction as this paper · 4 in the opposite direction
- negative
- negative
- negative
7 papers more in this group
See all 11 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.