Abstract
The normal window for application of thinning chemicals in apple extends from bloom until 3 weeks after bloom, when the fruit reach a mean diameter of ≈16 mm. After this time fruit are generally insensitive to standard chemical thinning sprays. The potential for the photosystem II (PSII) inhibitor metamitron and the ethylene precursor 1-aminocyclopropane carboxylic acid (ACC) to thin apple fruit after the traditional thinning window was investigated in field experiments over three years. A standard rescue thinning spray of carbaryl plus ethephon plus naphthaleneacetic acid (NAA) reduced fruit set of Gale ‘Gala’ if applied when the mean fruit diameter was 18, 20, and 27 mm in 2010, 2011, and 2012, respectively. The thinning activity of 400 mg·L −1 ACC was equivalent to the standard rescue thinning spray in 2010, whereas 350 mg·L −1 metamitron reduced fruit set more effectively than either the standard or ACC in 2010. Application of 400 mg·L −1 ACC plus 350 mg·L −1 metamitron when the mean fruit diameter was 18 mm reduced fruit set to almost no crop in 2010. The combination of metamitron plus ACC exhibited thinning activity after application at 25 and 33 mm mean fruit diameter in 2011 and 2012, respectively. Increased ethylene evolution was found in detached ‘GoldRush’ fruit 24 h after applications of ACC from 11 mm to 27 mm mean fruit diameter, but not when ACC was applied at 31 mm mean fruit diameter. Ethylene evolution was much higher after application of ACC at the 11 mm or 17 mm mean fruit diameter stage compared with application when fruit diameter was 23 mm or 27 mm. The thinning activity of ACC was related to the period of maximum ethylene response. The effects of delayed applications of ACC and metamitron on fruit set tended to be greater when these two chemicals were combined, suggesting that the creation of a carbohydrate stress and the capacity to convert ACC to ethylene are both required to trigger abscission of apple fruit larger than 18 mm in diameter.
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Claims 10
Claim · model-written summary
The rescue spray reduced Gale Gala fruit set at 18, 20 and 27 mm across three years.
- Taxon
- Gale ‘Gala’e0
- Treatment
- carbaryl plus ethephon plus naphthaleneacetic acid (NAA)e0
- Outcome
- fruit sete0
- Direction
- reducede0
- Value
- 18, 20, and 27 mme0
Not reportedComparator
Verbatim
e0“A standard rescue thinning spray of carbaryl plus ethephon plus naphthaleneacetic acid (NAA) reduced fruit set of Gale ‘Gala’ if applied when the mean fruit diameter was 18, 20, and 27 mm in 2010, 2011, and 2012, respectively”
Claim · model-written summary
ACC thinning matched the standard rescue spray in 2010.
- Taxon
- Apple
Malus domesticat0 - Treatment
- 400 mg·L −1 ACCe0
- Outcome
- thinning activitye0
- Direction
- equivalente0
- Comparator
- standard rescue thinning spraye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Apple”
e0“The thinning activity of 400 mg·L −1 ACC was equivalent to the standard rescue thinning spray in 2010”
Claim · model-written summary
Metamitron reduced fruit set more than the standard spray or ACC in 2010.
- Taxon
- AppleMalus domesticat0
- Treatment
- 350 mg·L −1 metamitrone0
- Outcome
- fruit sete0
- Direction
- reducede0
- Comparator
- the standard or ACCe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Apple”
e0“350 mg·L −1 metamitron reduced fruit set more effectively than either the standard or ACC in 2010”
Claim · model-written summary
Combined ACC and metamitron at 18 mm reduced fruit set to nearly no crop in 2010.
- Taxon
- AppleMalus domesticat0
- Treatment
- 400 mg·L −1 ACC plus 350 mg·L −1 metamitrone0
- Outcome
- fruit sete0
- Direction
- reducede0
- Qualifier
- when the mean fruit diameter was 18 mme0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Apple”
e0“Application of 400 mg·L −1 ACC plus 350 mg·L −1 metamitron when the mean fruit diameter was 18 mm reduced fruit set to almost no crop in 2010”
Claim · model-written summary
The combined treatment retained thinning activity at 25 and 33 mm fruit diameter.
- Taxon
- AppleMalus domesticat0
- Treatment
- metamitron plus ACCe0
- Outcome
- thinning activitye0
- Value
- 25 and 33 mme0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Apple”
e0“The combination of metamitron plus ACC exhibited thinning activity after application at 25 and 33 mm mean fruit diameter in 2011 and 2012, respectively”
Claim · model-written summary
ACC increased ethylene evolution in detached GoldRush fruit at 11–27 mm diameter.
- Taxon
- AppleMalus domesticat0
- Material
- ‘GoldRush’e0
- Treatment
- ACCe0
- Outcome
- ethylene evolutione0
- Direction
- Increasede0
- Qualifier
- from 11 mm to 27 mm mean fruit diametere0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Apple”
e0“Increased ethylene evolution was found in detached ‘GoldRush’ fruit 24 h after applications of ACC from 11 mm to 27 mm mean fruit diameter”
Claim · model-written summary
ACC at 31 mm did not increase ethylene evolution.
- Taxon
- AppleMalus domesticat0
- Material
- ‘GoldRush’e1
- Treatment
- ACC was applied at 31 mm mean fruit diametere0
- Outcome
- ethylene evolutione1
- Direction
- note0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Apple”
e0“but not when ACC was applied at 31 mm mean fruit diameter”
e1“Increased ethylene evolution was found in detached ‘GoldRush’ fruit”
Claim · model-written summary
Ethylene evolution after ACC was much higher at 11 or 17 mm than at 23 or 27 mm.
- Taxon
- AppleMalus domesticat0
- Treatment
- ACC at the 11 mm or 17 mm mean fruit diameter stagee0
- Outcome
- Ethylene evolutione0
- Direction
- much highere0
- Comparator
- application when fruit diameter was 23 mm or 27 mme0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Apple”
e0“Ethylene evolution was much higher after application of ACC at the 11 mm or 17 mm mean fruit diameter stage compared with application when fruit diameter was 23 mm or 27 mm”
Claim · model-written summary
ACC thinning activity was related to the period of maximal ethylene response.
- Taxon
- AppleMalus domesticat0
- Treatment
- ACCe0
- Outcome
- thinning activitye0
- Qualifier
- period of maximum ethylene responsee0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Apple”
e0“The thinning activity of ACC was related to the period of maximum ethylene response”
Claim · model-written summary
Combined ACC and metamitron tended to have greater fruit-set effects.
- Taxon
- AppleMalus domesticat0
- Treatment
- ACC and metamitrone0
- Outcome
- fruit sete0
- Direction
- greatere0
- Qualifier
- tended to bee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Apple”
e0“The effects of delayed applications of ACC and metamitron on fruit set tended to be greater when these two chemicals were combined”
The same questions in other papers
1-aminocyclopropanecarboxylic acid · yield · Malus domestica (apple)Results differ
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- no effect
- positive
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See all 8 papers →metamitron · yield · Malus domestica (apple)Positive and negative results
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- positive
- positive
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10 papers more in this group
See all 14 papers →1-aminocyclopropanecarboxylic acid · physiology: hormones · Malus domestica (apple)Results agree
3 papers in the same direction as this paper
- positive
- 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.