Abstract
SUMMARY‘Navel’ sweet orange [Citrus sinensis (Osbeck)] fruit with large, open, or protruding navel-ends are predisposed to splitting and navel-end rot, and provide an entry point that hampers the control of insect pests. A reliable method to reduce the size of navel-ends, without compromising tree health or fruit quality, would provide multiple benefits. The objective of this study, was to determine the optimal timing and concentration of foliar spray treatments with the synthetic auxin, 2,4-dichlorophenoxyacetic acid (2,4-D), to reduce the size of the navel-end on ‘Newhall Navel’ and ‘Washington Navel’ sweet orange fruit. The effects of 2,4-D treatment on fruit yield, tree health, and fruit quality, were also assessed. Treatments were applied to ‘Newhall Navel’ trees at a rate of 25 mg l−1 2,4-D at 2-weekly intervals, starting at full bloom (FB), and continuing until 4 weeks after 100% petal drop (PD). On ‘Washington Navel’ trees, 2,4-D was applied at 15 mg l−1, 25 mg l−1, or 35 mg l−1 at FB, or at 100% PD. The timing of the application of 2,4-D to increase the percentage of closed navel-ends, and to reduce their size, was more important than the concentration. Application of 2,4-D at FB significantly increased the percentage of fruit with closed navel-ends, and reduced their size in both ‘Newhall Navel’ and ‘Washington Navel’ fruit. Later treatments were ineffective. Application of 2,4-D at FB had no effect on fruit diameter, fruit yield, fruit number, or fruit quality parameters, except for a decrease in the fruit diameter:length ratio. In addition, successful 2,4-D spray treatment led to a slight decrease in fruit juice content. The application of a foliar spray of 2,4-D at FB, and at concentrations as low as 15 mg l−1, can be used to increase the percentage of closed navel-ends, reduce the number of culled fruit, and thereby improve the pack-out percentage for export quality ‘Navel’ sweet oranges.
Abstract from the paper’s OpenAlex record, shown for indexing and research. Copyright remains with the authors or the publisher. Read at the source ↗
The text the model read, with the source record’s inline markup (italics, sub- and superscripts) rendered and its character entities decoded; quote offsets refer to the raw text.
Claims 12
Claim · model-written summary
Application of 2,4-D at full bloom significantly increased the percentage of closed navel-ends in Newhall Navel sweet orange.
- Taxon
- Citrus sinensis
Citrus sinensise0 - Material
- ‘Newhall Navel’e1
- Organ / stage
- fruite1
- Treatment
- Application of 2,4-D at FBe1
- Outcome
- percentage of fruit with closed navel-endse1
- Direction
- increasede1
- Comparator
- Later treatmentse2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“‘Navel’ sweet orange [Citrus sinensis (Osbeck)]”
e1“Application of 2,4-D at FB significantly increased the percentage of fruit with closed navel-ends, and reduced their size in both ‘Newhall Navel’ and ‘Washington Navel’ fruit”
e2“Later treatments were ineffective”
Claim · model-written summary
Application of 2,4-D at full bloom significantly increased the percentage of closed navel-ends in Washington Navel sweet orange.
- Taxon
- Citrus sinensisCitrus sinensise0
- Material
- ‘Washington Navel’e1
- Organ / stage
- fruite1
- Treatment
- Application of 2,4-D at FBe1
- Outcome
- percentage of fruit with closed navel-endse1
- Direction
- increasede1
- Comparator
- Later treatmentse2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“‘Navel’ sweet orange [Citrus sinensis (Osbeck)]”
e1“Application of 2,4-D at FB significantly increased the percentage of fruit with closed navel-ends, and reduced their size in both ‘Newhall Navel’ and ‘Washington Navel’ fruit”
e2“Later treatments were ineffective”
Claim · model-written summary
Application of 2,4-D at full bloom significantly reduced navel-end size in Newhall Navel sweet orange.
- Taxon
- Citrus sinensisCitrus sinensise0
- Material
- ‘Newhall Navel’e1
- Organ / stage
- navel-endse1
- Treatment
- Application of 2,4-D at FBe1
- Outcome
- sizee1
- Direction
- reducede1
- Comparator
- Later treatmentse2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“‘Navel’ sweet orange [Citrus sinensis (Osbeck)]”
e1“Application of 2,4-D at FB significantly increased the percentage of fruit with closed navel-ends, and reduced their size in both ‘Newhall Navel’ and ‘Washington Navel’ fruit”
e2“Later treatments were ineffective”
Claim · model-written summary
Application of 2,4-D at full bloom significantly reduced navel-end size in Washington Navel sweet orange.
- Taxon
- Citrus sinensisCitrus sinensise0
- Material
- ‘Washington Navel’e1
- Organ / stage
- navel-endse1
- Treatment
- Application of 2,4-D at FBe1
- Outcome
- sizee1
- Direction
- reducede1
- Comparator
- Later treatmentse2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“‘Navel’ sweet orange [Citrus sinensis (Osbeck)]”
e1“Application of 2,4-D at FB significantly increased the percentage of fruit with closed navel-ends, and reduced their size in both ‘Newhall Navel’ and ‘Washington Navel’ fruit”
e2“Later treatments were ineffective”
Claim · model-written summary
Timing of 2,4-D application was more important than its concentration for increasing closed navel-ends and reducing navel-end size.
- Taxon
- Citrus sinensisCitrus sinensise0
- Treatment
- timing of the application of 2,4-De3
- Outcome
- percentage of closed navel-endse3
- Direction
- more importante3
- Comparator
- concentratione3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“‘Navel’ sweet orange [Citrus sinensis (Osbeck)]”
e3“The timing of the application of 2,4-D to increase the percentage of closed navel-ends, and to reduce their size, was more important than the concentration”
Claim · model-written summary
Application of 2,4-D at full bloom had no effect on fruit diameter, fruit yield or fruit number in Citrus sinensis.
- Taxon
- Citrus sinensisCitrus sinensise0
- Treatment
- Application of 2,4-D at FBe4
- Outcome
- fruit diameter, fruit yield, fruit numbere4
- Direction
- no effecte4
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“‘Navel’ sweet orange [Citrus sinensis (Osbeck)]”
e4“Application of 2,4-D at FB had no effect on fruit diameter, fruit yield, fruit number, or fruit quality parameters, except for a decrease in the fruit diameter:length ratio”
Claim · model-written summary
Application of 2,4-D at full bloom had no effect on fruit quality parameters in Citrus sinensis.
- Taxon
- Citrus sinensisCitrus sinensise0
- Treatment
- Application of 2,4-D at FBe4
- Outcome
- fruit quality parameterse4
- Direction
- no effecte4
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“‘Navel’ sweet orange [Citrus sinensis (Osbeck)]”
e4“Application of 2,4-D at FB had no effect on fruit diameter, fruit yield, fruit number, or fruit quality parameters, except for a decrease in the fruit diameter:length ratio”
Claim · model-written summary
Application of 2,4-D at full bloom decreased the fruit diameter:length ratio in Citrus sinensis.
- Taxon
- Citrus sinensisCitrus sinensise0
- Treatment
- Application of 2,4-D at FBe4
- Outcome
- fruit diameter:length ratioe4
- Direction
- decreasee4
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“‘Navel’ sweet orange [Citrus sinensis (Osbeck)]”
e4“Application of 2,4-D at FB had no effect on fruit diameter, fruit yield, fruit number, or fruit quality parameters, except for a decrease in the fruit diameter:length ratio”
Claim · model-written summary
Successful 2,4-D spray treatment slightly decreased fruit juice content in Citrus sinensis.
- Taxon
- Citrus sinensisCitrus sinensise0
- Treatment
- successful 2,4-D spray treatmente5
- Outcome
- fruit juice contente5
- Direction
- decreasee5
- Qualifier
- slighte5
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“‘Navel’ sweet orange [Citrus sinensis (Osbeck)]”
e5“successful 2,4-D spray treatment led to a slight decrease in fruit juice content”
Claim · model-written summary
The authors recommend a foliar 2,4-D spray at full bloom to improve the pack-out percentage of export-quality Navel sweet oranges.
- Taxon
- Citrus sinensisCitrus sinensise0
- Treatment
- foliar spray of 2,4-D at FBe6
- Outcome
- pack-out percentagee6
- Qualifier
- at concentrations as low as 15 mg l−1e6
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“‘Navel’ sweet orange [Citrus sinensis (Osbeck)]”
e6“The application of a foliar spray of 2,4-D at FB, and at concentrations as low as 15 mg l−1, can be used to increase the percentage of closed navel-ends, reduce the number of culled fruit, and thereby improve the pack-out percentage for export quality ‘Navel’ sweet oranges”
Claim · model-written summary
A foliar 2,4-D spray at full bloom can reduce the number of culled fruit in Citrus sinensis.
- Taxon
- Citrus sinensisCitrus sinensise0
- Treatment
- foliar spray of 2,4-D at FBe6
- Outcome
- number of culled fruite6
- Direction
- reducee6
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“‘Navel’ sweet orange [Citrus sinensis (Osbeck)]”
e6“The application of a foliar spray of 2,4-D at FB, and at concentrations as low as 15 mg l−1, can be used to increase the percentage of closed navel-ends, reduce the number of culled fruit, and thereby improve the pack-out percentage for export quality ‘Navel’ sweet oranges”
Claim · model-written summary
Later 2,4-D treatments were ineffective, compared with application at full bloom, for navel-end outcomes in Citrus sinensis.
- Taxon
- Citrus sinensisCitrus sinensise0
- Treatment
- Later treatmentse2
- Outcome
- ineffectivee2
- Direction
- ineffectivee2
- Comparator
- Application of 2,4-D at FBe1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“‘Navel’ sweet orange [Citrus sinensis (Osbeck)]”
e1“Application of 2,4-D at FB significantly increased the percentage of fruit with closed navel-ends, and reduced their size in both ‘Newhall Navel’ and ‘Washington Navel’ fruit”
e2“Later treatments were ineffective”
The same questions in other papers
2,4-D · yield · Citrus sinensis (sweet orange)Positive and negative results
1 paper in the same direction as this paper · 13 in the opposite direction
- positive
- positive
- positive
11 papers more in this group
See all 15 papers →2,4-D · quality: grain · Citrus sinensis (sweet orange)Results agree
1 paper in the same direction as this paper
- no effect
2,4-D · growth · Citrus sinensis (sweet orange)Results agree
3 papers in the same direction as this paper
- positive
- positive
- positive
application · molecular: metabolites · Citrus sinensis (sweet orange)Positive and negative results
1 paper in the same direction as this paper · 13 in the opposite direction
- positive
- positive
- positive
11 papers more in this group
See all 15 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.