Bloom and Postbloom Thinner Effects and Interactions on ‘Gala’ Fruit Growth Rate, Return Bloom, and Yield Responses at Three Locations
Multistep chemical thinning programs have been widely recommended in the eastern United States; however, adoption of bloom thinners is limited. With caustic blossom thinners, narrow effective application timings and concerns related to spring frost damage are barriers for commercial use in this regi...
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| Format: | Article |
| Language: | English |
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American Society for Horticultural Science (ASHS)
2023-10-01
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| Series: | HortScience |
| Subjects: | |
| Online Access: | https://journals.ashs.org/hortsci/view/journals/hortsci/58/11/article-p1418.xml |
| _version_ | 1827355401135325184 |
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| author | James E. Larson Duane W. Greene James R. Schupp Christopher D. Clavet Thomas M. Kon |
| author_facet | James E. Larson Duane W. Greene James R. Schupp Christopher D. Clavet Thomas M. Kon |
| author_sort | James E. Larson |
| collection | DOAJ |
| description | Multistep chemical thinning programs have been widely recommended in the eastern United States; however, adoption of bloom thinners is limited. With caustic blossom thinners, narrow effective application timings and concerns related to spring frost damage are barriers for commercial use in this region. If effective and safe, use of hormonal blossom thinners for apple would be an attractive alternative. We evaluated the effects and interactions of bloom thinners [6-benzyladenine (BA) and lime sulfur (LS, or calcium polysulfide) + stylet oil (LS+SO)] and a postbloom thinner (NAA) in the context of a multistep, carbaryl-free thinning program across three locations. Experiments were conducted in 2017 and 2018 on mature ‘Gala’ in North Carolina, Massachusetts, and Pennsylvania, USA. In four of six studies, BA at bloom increased the efficacy of postbloom NAA and reduced crop density (P < 0.08). Postbloom NAA generally increased fruit relative growth rate (RGR) and reduced crop density. However, where NAA failed to reduce crop load, there was a negative influence on RGR. BA and LS+SO increased RGR in one of six studies; however, BA was generally ineffective as a blossom thinner, whereas LS+SO was more effective. Nevertheless, BA applied at bloom may have utility as part of a multistep thinning program. As a part of a multistep thinning program, BA applied at bloom may be useful in increasing efficacy of postbloom applications, particularly when use of caustic blossom thinners is not permitted. |
| first_indexed | 2024-03-08T04:10:20Z |
| format | Article |
| id | doaj.art-2eb0cc36718d4a2f903e727e7ed5f67c |
| institution | Directory Open Access Journal |
| issn | 2327-9834 |
| language | English |
| last_indexed | 2024-03-08T04:10:20Z |
| publishDate | 2023-10-01 |
| publisher | American Society for Horticultural Science (ASHS) |
| record_format | Article |
| series | HortScience |
| spelling | doaj.art-2eb0cc36718d4a2f903e727e7ed5f67c2024-02-08T20:44:17ZengAmerican Society for Horticultural Science (ASHS)HortScience2327-98342023-10-015811https://doi.org/10.21273/HORTSCI17353-23Bloom and Postbloom Thinner Effects and Interactions on ‘Gala’ Fruit Growth Rate, Return Bloom, and Yield Responses at Three LocationsJames E. Larson0Duane W. Greene1James R. Schupp2Christopher D. Clavet3Thomas M. Kon4Department of Horticultural Science, North Carolina State UniversityStockbridge School of Agriculture, University of MassachusettsDepartment of Plant Science, The Pennsylvania State UniversityDepartment of Horticultural Science, North Carolina State UniversityDepartment of Horticultural Science, North Carolina State UniversityMultistep chemical thinning programs have been widely recommended in the eastern United States; however, adoption of bloom thinners is limited. With caustic blossom thinners, narrow effective application timings and concerns related to spring frost damage are barriers for commercial use in this region. If effective and safe, use of hormonal blossom thinners for apple would be an attractive alternative. We evaluated the effects and interactions of bloom thinners [6-benzyladenine (BA) and lime sulfur (LS, or calcium polysulfide) + stylet oil (LS+SO)] and a postbloom thinner (NAA) in the context of a multistep, carbaryl-free thinning program across three locations. Experiments were conducted in 2017 and 2018 on mature ‘Gala’ in North Carolina, Massachusetts, and Pennsylvania, USA. In four of six studies, BA at bloom increased the efficacy of postbloom NAA and reduced crop density (P < 0.08). Postbloom NAA generally increased fruit relative growth rate (RGR) and reduced crop density. However, where NAA failed to reduce crop load, there was a negative influence on RGR. BA and LS+SO increased RGR in one of six studies; however, BA was generally ineffective as a blossom thinner, whereas LS+SO was more effective. Nevertheless, BA applied at bloom may have utility as part of a multistep thinning program. As a part of a multistep thinning program, BA applied at bloom may be useful in increasing efficacy of postbloom applications, particularly when use of caustic blossom thinners is not permitted.https://journals.ashs.org/hortsci/view/journals/hortsci/58/11/article-p1418.xmlabscissioncrop load managementfruit setfruit sizeplant growth regulatormalus ×domestica |
| spellingShingle | James E. Larson Duane W. Greene James R. Schupp Christopher D. Clavet Thomas M. Kon Bloom and Postbloom Thinner Effects and Interactions on ‘Gala’ Fruit Growth Rate, Return Bloom, and Yield Responses at Three Locations HortScience abscission crop load management fruit set fruit size plant growth regulator malus ×domestica |
| title | Bloom and Postbloom Thinner Effects and Interactions on ‘Gala’ Fruit Growth Rate, Return Bloom, and Yield Responses at Three Locations |
| title_full | Bloom and Postbloom Thinner Effects and Interactions on ‘Gala’ Fruit Growth Rate, Return Bloom, and Yield Responses at Three Locations |
| title_fullStr | Bloom and Postbloom Thinner Effects and Interactions on ‘Gala’ Fruit Growth Rate, Return Bloom, and Yield Responses at Three Locations |
| title_full_unstemmed | Bloom and Postbloom Thinner Effects and Interactions on ‘Gala’ Fruit Growth Rate, Return Bloom, and Yield Responses at Three Locations |
| title_short | Bloom and Postbloom Thinner Effects and Interactions on ‘Gala’ Fruit Growth Rate, Return Bloom, and Yield Responses at Three Locations |
| title_sort | bloom and postbloom thinner effects and interactions on gala fruit growth rate return bloom and yield responses at three locations |
| topic | abscission crop load management fruit set fruit size plant growth regulator malus ×domestica |
| url | https://journals.ashs.org/hortsci/view/journals/hortsci/58/11/article-p1418.xml |
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