Mechanical Crop Load Management (CLM) Improves Fruit Quality and Reduces Fruit Drop and Alternate Bearing in European Plum (<i>Prunus domestica</i> L.)
(1) Background: With ca. 10 million tons of annual production worldwide, the plum (<i>Prunus ssp</i>.) ranks as a major fruit crop and can suffer from small fruit size, premature fruit drop and alternate bearing, which are addressed in this paper using a range of crop load management (CL...
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MDPI AG
2020-09-01
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| Series: | Horticulturae |
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| Online Access: | https://www.mdpi.com/2311-7524/6/3/52 |
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| author | Sebastian Lammerich Achim Kunz Lutz Damerow Michael Blanke |
| author_facet | Sebastian Lammerich Achim Kunz Lutz Damerow Michael Blanke |
| author_sort | Sebastian Lammerich |
| collection | DOAJ |
| description | (1) Background: With ca. 10 million tons of annual production worldwide, the plum (<i>Prunus ssp</i>.) ranks as a major fruit crop and can suffer from small fruit size, premature fruit drop and alternate bearing, which are addressed in this paper using a range of crop load management (CLM) tools. (2) Methods: Sixty 10-year-old European plum cv. “Ortenauer” trees on dwarfing St. Julien INRA GF 655/2 rootstock (slender spindle; 4.25 × 2.80 m) in a commercial orchard near Bonn (50°N), Germany, were thinned in 2 years and flower intensity assessed in the following year. Thinning was performed either mechanically (type Bonn/Baum) or chemically, with ATS (ammonium thiosulfate) or ethephon (Flordimex), or by a combination of mechanical and chemical methods, to improve fruit quality and the proportion of Class 1 fruit. Adjacent un-thinned trees served as controls. (3) Results: Natural fruit drop in June was reduced from 290 fruits per tree in the un-thinned controls to 265 fruits after ATS blossom treatment, and to 148 fruits after mechanical thinning at 380 rpm at a 5 km/h tractor speed at full bloom. The un-thinned control trees developed a large number of small, undersized fruits. The yield of Class 1 fruits increased per tree from 47% in the un-thinned controls, up to 69% after crop load management. Sugar content and fruit firmness were unaffected. (4) Conclusions: The study has shown that fruit quality (i.e., fruit size) and financial returns could be improved by either mechanical (380 rpm at 5 km/h) or chemical thinning, or a combination of both. |
| first_indexed | 2024-03-10T16:37:39Z |
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| id | doaj.art-3cbc57dc6b464e60ae23bffb23abbd74 |
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| language | English |
| last_indexed | 2024-03-10T16:37:39Z |
| publishDate | 2020-09-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Horticulturae |
| spelling | doaj.art-3cbc57dc6b464e60ae23bffb23abbd742023-11-20T12:19:21ZengMDPI AGHorticulturae2311-75242020-09-01635210.3390/horticulturae6030052Mechanical Crop Load Management (CLM) Improves Fruit Quality and Reduces Fruit Drop and Alternate Bearing in European Plum (<i>Prunus domestica</i> L.)Sebastian Lammerich0Achim Kunz1Lutz Damerow2Michael Blanke3INRES-Horticultural Science, University of Bonn, D-53121 Bonn, GermanyINRES-Horticultural Science, University of Bonn, D-53121 Bonn, GermanyAgricultural Engineering Department, University of Bonn, D-53121 Bonn, GermanyINRES-Horticultural Science, University of Bonn, D-53121 Bonn, Germany(1) Background: With ca. 10 million tons of annual production worldwide, the plum (<i>Prunus ssp</i>.) ranks as a major fruit crop and can suffer from small fruit size, premature fruit drop and alternate bearing, which are addressed in this paper using a range of crop load management (CLM) tools. (2) Methods: Sixty 10-year-old European plum cv. “Ortenauer” trees on dwarfing St. Julien INRA GF 655/2 rootstock (slender spindle; 4.25 × 2.80 m) in a commercial orchard near Bonn (50°N), Germany, were thinned in 2 years and flower intensity assessed in the following year. Thinning was performed either mechanically (type Bonn/Baum) or chemically, with ATS (ammonium thiosulfate) or ethephon (Flordimex), or by a combination of mechanical and chemical methods, to improve fruit quality and the proportion of Class 1 fruit. Adjacent un-thinned trees served as controls. (3) Results: Natural fruit drop in June was reduced from 290 fruits per tree in the un-thinned controls to 265 fruits after ATS blossom treatment, and to 148 fruits after mechanical thinning at 380 rpm at a 5 km/h tractor speed at full bloom. The un-thinned control trees developed a large number of small, undersized fruits. The yield of Class 1 fruits increased per tree from 47% in the un-thinned controls, up to 69% after crop load management. Sugar content and fruit firmness were unaffected. (4) Conclusions: The study has shown that fruit quality (i.e., fruit size) and financial returns could be improved by either mechanical (380 rpm at 5 km/h) or chemical thinning, or a combination of both.https://www.mdpi.com/2311-7524/6/3/52European plum (<i>Prunus domestica</i> L.)alternate bearingcrop load management (CLM)fruit dropfruit qualitymechanical thinning |
| spellingShingle | Sebastian Lammerich Achim Kunz Lutz Damerow Michael Blanke Mechanical Crop Load Management (CLM) Improves Fruit Quality and Reduces Fruit Drop and Alternate Bearing in European Plum (<i>Prunus domestica</i> L.) Horticulturae European plum (<i>Prunus domestica</i> L.) alternate bearing crop load management (CLM) fruit drop fruit quality mechanical thinning |
| title | Mechanical Crop Load Management (CLM) Improves Fruit Quality and Reduces Fruit Drop and Alternate Bearing in European Plum (<i>Prunus domestica</i> L.) |
| title_full | Mechanical Crop Load Management (CLM) Improves Fruit Quality and Reduces Fruit Drop and Alternate Bearing in European Plum (<i>Prunus domestica</i> L.) |
| title_fullStr | Mechanical Crop Load Management (CLM) Improves Fruit Quality and Reduces Fruit Drop and Alternate Bearing in European Plum (<i>Prunus domestica</i> L.) |
| title_full_unstemmed | Mechanical Crop Load Management (CLM) Improves Fruit Quality and Reduces Fruit Drop and Alternate Bearing in European Plum (<i>Prunus domestica</i> L.) |
| title_short | Mechanical Crop Load Management (CLM) Improves Fruit Quality and Reduces Fruit Drop and Alternate Bearing in European Plum (<i>Prunus domestica</i> L.) |
| title_sort | mechanical crop load management clm improves fruit quality and reduces fruit drop and alternate bearing in european plum i prunus domestica i l |
| topic | European plum (<i>Prunus domestica</i> L.) alternate bearing crop load management (CLM) fruit drop fruit quality mechanical thinning |
| url | https://www.mdpi.com/2311-7524/6/3/52 |
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