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Investigating the origin and extent of variation in apple fruit quality
Thesis (MScAgric)--Stellenbosch University, 2022.
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| Language: | en_ZA |
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Stellenbosch : Stellenbosch University
2022
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| _version_ | 1867613918908645376 |
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| access_status_str | Open Access |
| author | Van Lingen, Andrew Frank William |
| author2 | Louw, Esme D. |
| author_browse | Louw, Esme D. Van Lingen, Andrew Frank William |
| author_facet | Louw, Esme D. Van Lingen, Andrew Frank William |
| author_sort | Van Lingen, Andrew Frank William |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description | Thesis (MScAgric)--Stellenbosch University, 2022. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/124975 |
| institution | Stellenbosch University (South Africa) |
| language | en_ZA |
| last_indexed | 2026-06-10T12:43:47.401Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2022 |
| publishDateRange | 2022 |
| publishDateSort | 2022 |
| publisher | Stellenbosch : Stellenbosch University |
| publisherStr | Stellenbosch : Stellenbosch University |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/124975 Investigating the origin and extent of variation in apple fruit quality Van Lingen, Andrew Frank William Louw, Esme D. Steyn, Wiehann J. Stellenbosch University. Faculty of Agrisciences. Dept. of Horticulture. Apples Fruit -- Quality -- South Africa Apples -- Effect of temperature on Malus Starch Apples -- Flowering Firmness Apples -- Environmental aspects UCTD Thesis (MScAgric)--Stellenbosch University, 2022. ENGLISH ABSTRACT: Developed countries with abundant food sources, have become more discerning of apple fruit quality. In addition to specific qualities that consumers may find desirable, variation in quality within a batch is perceived negatively, regardless if that fruit would have been acceptable when presented individually. Variation in apple fruit quality and maturity present a challenge for producers and complicate the postharvest handling and marketing of fruit. Understanding the origin and consequence of variation can lead the industry towards mitigating such issues. The variance components: region, orchard, tree, canopy position (top vs bottom fruit, sun exposed vs shaded fruit) and bearing wood (shoots vs spurs) were, investigated. Variation in ‘Golden Delicious’ fruit quality and maturity was extensive at harvest and in some cases even greater after storage. The largest contributors to total variation in both seasons was orchard-to-orchard and tree- to-tree differences. Region contributed less to overall variation than expected and variation in starch conversion percentage (SC%) was prevalent in both Elgin and the Koue Bokkeveld with the bottom branches having a higher SC% than top branches. Position within a tree interacting with light exposure influenced fruit firmness with sun exposed fruit and fruit from the top branches having a higher firmness. The effect persisted through to fruit after storage showing greater differences between the positions. Fruit peel lightness values and hue angles showed moderate and strong correlations from at harvest to after storage but correlated poorly with other variables. Relative bloom date (RBD) was investigated as an additional source of variation but accounted for less of the variation than anticipated. RBD had a stronger influence on maturity in the milder winter region than the colder winter region, with early clusters producing fruit with the higher starch conversion percentage than late cluster in Elgin, while there was no difference in the Koue Bokkeveld. The effect of RBD on fruit mass was commercially consequential in both regions with late blooming clusters producing the smallest fruit. Flower quality was also evaluated in warm and cold site, with number of flowers per cluster, receptacle diameter, pedicel length and dry weight of flower clusters being measured across bloom time (early and late), canopy position (top and bottom) and spur age (2-year-old spurs, 3-year-old spurs, old spurs, and shoots). Greater dry weight was observed for early clusters in the colder site than for late clusters, but there was no significant difference in the warmer site. The effect of bearing wood on flower cluster dry mass showed that flowers on shoots in the warmer site had the greatest dry mass while those on old spurs in the colder site had the highest dry mass. This translated through to fruit mass at harvest, where the heaviest fruit in the warmer site were found on shoots, and old spurs produced the heaviest fruit in the colder site. Results in this study confirm, that separate harvesting of the bottom and top halves of trees and sorting fruit on colour before storage, would increase the level of uniformity in batches of fruit. It should be noted though that colour sorting would not decrease the variance in maturity within batches of fruit but the fruit colour within a box or bag would be more consistent. By judicious pruning, summer pruning and branch removal, light distribution would be improved in existing orchards and possible result in less overall variation. The use of ethylene inhibitors such as aminoethoxyvinylglycine or 1- methyl-cyclopropene could also reduce variation in maturity at harvest. For the planting of new apple orchards, higher tree densities with thinner canopies are recommended and shade netting should be considered. Rest breaking programmes should be aimed at reducing the variance in flowering time between the bottom and top halves of trees. AFRIKAANSE OPSOMMING: Ontwikkelde lande, met ʼn oorvloed voedselbronne, het meer oordeelkundig geword rakende die gehalte van appels. Benewens spesifieke eienskappe wat verbruikers wenslik mag vind, word variasie in kwaliteit binne 'n karton of sak appels as negatief ervaar, ongeag of dieselfde vrugte aanvaarbaar sou wees as dit individueel aangebied was. Variasie in appelvrugkwaliteit en rypheid bied 'n uitdaging vir produsente en bemoeilik die na-oes hantering en bemarking van vrugte. Die verstaan van die oorsprong en gevolge van hierdie variasie, kan die appelbedryf lei om hierdie probleme op te los. Die variansie komponente: produksie streek, boord, boom, blaredak posisie (bo of onder en sonblootgestelde teenoor skadu vrugte) en drahout (lote of spore) is ondersoek. Variasie in ‘Golden Delicious’ vrugkwaliteit en rypheid was verrassend groot tydens oes en in sommige gevalle selfs groter na opberging. Die grootste bydraers tot die totale variasie in beide seisoene was boord-tot- boord en boom-tot-boom verskille. Produksie streek het minder bygedra tot algehele variasie as wat verwag was en variasie in styselomsettingspersentasie (SC%) was teenwoordig in beide Elgin en die Koue Bokkeveld, waar die onderste takke 'n hoër SC% as die boonste takke getoon het. Posisie binne 'n boom, wat met ligblootstelling in wisselwerking was, het 'n effek op die vrugfermheid gehad. Sonblootgestelde vrugte en vrugte van die boonste takke het 'n hoër fermheid gehad. Die effek het voortgeduur tydens opberging, waar groter verskille tussen die posisies aangetoon was. Ligheidswaardes van die skil en kleurhoeke het matige en sterk korrelasies getoon vanaf oes tot na opberging, maar was swak gekorreleerd met ander veranderlikes. Relatiewe blomdatum (RBD) is ondersoek om die oorsprong van die variasie te probeer aanspreek, en daar is gevind dat dit minder tot die variasie bygedra het as wat verwag was. RBD het 'n sterker invloed op rypheid van vrugte in die warmer winterstreek as die koeler winterstreek gehad. In Elgin het vroeë trosse se vrugte ʼn hoër styselomsettingspersentasie as laat trosse getoon, terwyl daar geen verskille in die Koue Bokkeveld was nie. Die effek van RBD op vrugmassa was kommersieel betekenisvol in beide streke, waar laatbloeiende trosse die kleinste vrugte geproduseer het. Blomgehalte was ook in beide ʼn kouer en ʼn warmer proefperseel geëvalueer, met aantal blomme per tros, deursnee van die blombodem, steellengte en droë gewig van blomtrosse bepaal tydens blomtyd (vroeg en laat), blaredakposisie (bo en onder) en drahoutouderdom (2-jarige spore, 3-jarige spore, ou spore, en lote). Vroeë trosse was swaarder in die kouer perseel as laat trosse, maar daar was geen betekenisvolle verskil in droë gewig in die warmer perseel nie. Die effek van drahout op die blomtrosse se droë massa het getoon dat blomme op lote in die warmer perseel die grootste droë massa gehad het terwyl dié op ou spore in die kouer perseel die hoogste droë massa gehad het. Dit het deurgevoer na vrugmassa tydens oes, waar die swaarste vrugte in Elgin (warmer area) op lote gevind is, en ou spore die swaarste vrugte in die Koue Bokkeveld (kouer area) opgelewer het. Resultate in hierdie studie bevestig dat die eenvormigheid in vrugte kwaliteit verhoog kan word indien die onderste en boonste helftes van bome apart geoes word, asook deur die sortering van vrugte volgens hul kleur voor opberging plaasvind. Daar moet egter gelet word dat kleursortering nie die variasie in rypheid binne ‘n besending vrugte sal verminder nie, maar eerder sal verseker dat die vrugkleur binne 'n boks of sak meer uniform sal wees. Deur oordeelkundige snoei, somersnoei en takverwydering sal ligverspreiding in bestaande boorde verbeter kan word, en moontlik minder algehele vrugvariasie tot gevolg hê. Die gebruik van etileen-inhibeerders soos aminoetoksivinielglisien of 1-metiel-siklopropeen kan ook variasie in rypheid tydens oes verminder. Vir die vestiging van nuwe appelboorde, word hoër boomdigthede met dunner blaredakke aanbeveel en skadunet kan ook oorweeg word. Rusbreekprogramme moet daarop gemik wees om die variasie in blomtyd tussen die onderste en boonste helftes van bome te verminder. Masters 2022-03-10T21:17:24Z 2022-04-29T09:44:26Z 2022-03-10T21:17:24Z 2022-04-29T09:44:26Z 2022-04 Thesis http://hdl.handle.net/10019.1/124975 en_ZA Stellenbosch University viii, 162 pages : illustrations (some color) application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Apples Fruit -- Quality -- South Africa Apples -- Effect of temperature on Malus Starch Apples -- Flowering Firmness Apples -- Environmental aspects UCTD Van Lingen, Andrew Frank William Investigating the origin and extent of variation in apple fruit quality |
| title | Investigating the origin and extent of variation in apple fruit quality |
| title_full | Investigating the origin and extent of variation in apple fruit quality |
| title_fullStr | Investigating the origin and extent of variation in apple fruit quality |
| title_full_unstemmed | Investigating the origin and extent of variation in apple fruit quality |
| title_short | Investigating the origin and extent of variation in apple fruit quality |
| title_sort | investigating the origin and extent of variation in apple fruit quality |
| topic | Apples Fruit -- Quality -- South Africa Apples -- Effect of temperature on Malus Starch Apples -- Flowering Firmness Apples -- Environmental aspects UCTD |
| url | http://hdl.handle.net/10019.1/124975 |
| work_keys_str_mv | AT vanlingenandrewfrankwilliam investigatingtheoriginandextentofvariationinapplefruitquality |