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Quantifying the role of vapour pressure deficit in the development of lenticel breakdown in ‘Braeburn’ apple
Thesis (MScAgric)--Stellenbosch University, 2021.
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| Language: | en_ZA |
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Stellenbosch : Stellenbosch University
2021
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| _version_ | 1867614006278094848 |
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| access_status_str | Open Access |
| author | Mzize, Nolubabalo |
| author2 | Lotze, Elmi |
| author_browse | Lotze, Elmi Mzize, Nolubabalo |
| author_facet | Lotze, Elmi Mzize, Nolubabalo |
| author_sort | Mzize, Nolubabalo |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description | Thesis (MScAgric)--Stellenbosch University, 2021. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/123921 |
| institution | Stellenbosch University (South Africa) |
| language | en_ZA |
| last_indexed | 2026-06-10T12:45:09.986Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2021 |
| publishDateRange | 2021 |
| publishDateSort | 2021 |
| publisher | Stellenbosch : Stellenbosch University |
| publisherStr | Stellenbosch : Stellenbosch University |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/123921 Quantifying the role of vapour pressure deficit in the development of lenticel breakdown in ‘Braeburn’ apple Mzize, Nolubabalo Lotze, Elmi Crouch, E. M. Stellenbosch University. Faculty of Agrisciences. Dept. of Horticulture. Apples (Braeburn) -- Breeding Apples (Braeburn) -- Quality Apples -- Storage -- Diseases and injuries Apples -- Effect of cold on Lenticel breakdown Fruit -- Storage -- Cooling UCTD Thesis (MScAgric)--Stellenbosch University, 2021. ENGLISH ABSTRACT: Lenticel breakdown (LB) is a physiological disorder that can develop in different apple cultivars including Braeburn during cold storage and shipping. Several researchers mentioned various pre and post-harvest factors influencing LB, however, the effect of vapour pressure deficit (VPD) has not been discussed. In trial 1, the anatomical and morphological development of lenticels on ‘Braeburn’ fruit was studied from 40 to 166 DAFB, and fruit harvested post-optimum to increase risk of LB incidence. Fruit from the East side had smaller epidermal and hypodermal cell sizes, a higher number of lenticels per fruit, open lenticel and developed more LB. Lenticel developmental stage was not influenced by canopy side and transitioning of stomata into lenticel was only observed from 82DAFB onwards, a bit later compared to other apple cultivars. In trial 2, LB incidence was related to: delayed cooling (24 h, 0 h) and the use of wet blankets in the orchard (+/- Blanket), in ‘Braeburn’ after harvest. The study showed that 24 h– Blanket increased cumulative VPD significantly and the 0 h (immediate cooling) and wet blanket reduced cumulative VPD significantly over time. Delayed cooling and wet blanket (24 h + Blanket) contributed to LB incidence, with the 24 h+Blanket treatment developing 7%, 0 h-Blanket 5% and other treatments, 3% (2019/2020). No significant effects were found in 2018/2019. Delayed cooling advances maturity whereas use of wet blanket and immediate cooling-maintained fruit quality. In trial 3, LB incidence was related to: two precooling types (Forced air (FAC) and passive cooling (PC)) and different times and temperatures (-1 °C and 3 °C) with reference to cooling speed before storage. Passive cooling is a non-mechanical cooling system that cools fruit inside the cool room, while forced air cooling is a technique that exposes fruit to forced cooled air at a higher pressure, either in situ, though a tunnel or in the cool room. The study revealed no significant effect between treatments in cooling speed, time and temperature (2018/2019), yet, the -1 °C temperature had a faster cooling speed and shorter cooling time (2019/2020). The PC -1 °C showed increase in cumulative VPD, whilst FAC -1 °C lowered cumulative VPD significantly. LB incidence, fruit weight loss and firmness were not significantly affected by the treatments. In trial 4, LB incidence was related to: the use of different fan speeds, liners and packaging on re-cooling rate during 6 weeks of simulated shipping. Fan speeds 2 and 3 had a rapid re- cooling rate, shorter re-cooling time and higher cumulative VPD compared to Fan speed 1. Fan speed 3 showed significantly increased fruit weight loss compared to Fan speeds 1 and 2. The study did not show any significant effect in LB incidence, although treatments had a significant effect on fruit quality. Punched and Micro-perforated liners showed a slower re-cooling rate, extended re-cooling time, lower cumulative VPD and reduced fruit weight loss. Both liners significantly and conversely developed more LB, whereas No liner maintained fruit quality at optimum levels. The application of a wet blanket shortly after harvest, immediate cooling (0 h), no application of wet blanket, 24 h delay cooling (24 h) thereafter and packing fruit without liners showed a reduction in LB incidence, but additional studies are required to obtain conclusive results. Thus, whilst fruit quality is maintained, none of the postharvest treatments consistently resulted in LB increases/decreases and therefore we postulated that LB incidence is initiated pre-harvest, as result of a self-defence mechanism of fruit exposed to stress conditions, and not primarily by storage regimes. AFRIKAANSE OPSOMMING: Lentiselafbraak (LB) is ‘n fisiologiese defek wat in verskillende appel kultivars kan ontwikkel, insluitende ‘Braeburn’, gedurende koelopberging en verskeping. Menigde navorsers het verskeie voor- en na-oes faktore genome wat LB beïnvloed, maar die effek van dampdruk tekort (VPD) is nog nie bespreek nie. In proef 1 is die anatomiese- en morfologiese ontwikkeling van lentiselle op ‘Braeburn’ vrugte ondersoek vanaf 40 – 166 DNVB, voordat vrugte oorryp ge-oes is om die risiko van LB voorkoms te verhoog. Vrugte van die Oostekant het kleiner epidermale en hipodermale selle getoon, ‘n hoër aantal lentiselle per vrug, oop lentiselle en meer LB. Lentisel ontwikkeling stadia is nie beïnvloed deur die boomkant nie en die verandering van huidmondjies in lentiselle is eers waargeneem vanaf 82 DNVB, wat later is as voorheen gemeld in ander kultivars. In proef 2 is LB voorkoms verbind met: vertraagde verkoeling (24h, 0 h) en die gebruik van komberse (+/- Blanket) in ‘Braeburn’ na oes. Die studie het gewys dat 24 h-Blanket kummulatiewe VPD betekenisvol verhoog het dat die 0 h (onmiddellike verkoeling) en nat kombers oor tyd die kummulaiewe VPD betekenisvol verminder het. Vertraagde verkoeling en nat komberse ( 24 h + Blanket) het bygedra tot LB voorkoms, met die ontwikkeling van 7% in die 24h+Blanket behandeling, 5% in die 0h-Blanket en 3%, by die res van die behandelings (2019/2020). Geen betekenisvolle effek is in 2018/2019 gevind nie. Vertraagde verkoeling het rypheid verhaas teenoor die gebruik van nat komberse en onmiddelike verkoeling, wat vrugkwaliteit behou het. In proef 3 is LB voorkoms verbind met: twee voor-verkoelingstipes (Geforseerde lug (FAC) en passiewe verkoeling (PC)) en verskillende tye en temperature (-1 °C en 3°C) met verwysing na die verkoelingspoed voor opberging. Passiewe verkoeling is ‘n nie-meganiese verkoelingsisteem wat vrugte in die koelkamer verkoel, terwyl geforseerde verkoeling ‘n tegniek behels wat vrugte blootstel aan geforseerde verkoelde lug by ‘n hoër druk in situ, in ‘n tonnel of koelkamer. Die studie het getoon dat daar geen betekenisvolle effek was tussen behandelings in verkoelingspoed, tyd en temperatuur nie (2018/2019), nietemin het die -1 °C temperatuur ‘n vinniger verkoelingspoed en korter verkoelingstyd gehad (2019/2020). PC -1°C het die kummulatiewe VPD betekenisvol verminder. LB voorkoms, verlies aan vrugmassa en fermheid is nie betekenisvol beïnvloed deur die behandelings nie. In proef 4 is LB voorkoms verbind met: die gebruik van verskillende waaier spoede, voerings en verpakking op herverkoelingstempo gedurende 6 weke van gesimuleerde verskeping. Waaierspoed 2 en 3 het ‘n vinnige herverkoelingstempo, korter herverkoelingstyd en hoër geakkumuleerde VDP as Waarspoed 1 gehad. Waaierspoed 3 het ‘n betekenisvolle toename in vrugmassaverlies getoon teenoor Waaerspoed 1 en 2. Die studie het nie enige betekenisvolle verskille in LB voorkoms getoon nie, alhoewel behandelings ‘n betekenisvolle effek op vrugkwalteit gehad het. Geperforeerde and Mikro-geperforeerde voerings het’n stadiger herverkoelingstempo, verlengde herverkoelingstyd, laer kummulatiewe VPD en verminderde vrugmassaverlies getoon. Beide voerings het onverwags betekenisvolle LB ontwikkel, teenoor die Geen voering wat vrugkwaliteit by optimum vlakke gehou het. Die aanwending van ‘n nat kombers kort na oes, onmiddellike verkoeling (0 h), geen toediening van nat komberse, 24 h vertraagde verkoeling (24 h) daarna en verpakking sonder voerings het LB voorkoms verminder, maar nog studies word benodig vir beslissende gevolgtrekkings. Dus kom dit voor dat, terwyl vrugkwaliteit behou word, geen van die na-oes behandelings konsekwent LB verminder/veroorsaak het nie en daarom postuleer ons dat LB voorkoms voor-oes geïnisieer word as resultaat van ‘n selfbeskermende meganisme van vrugte wat blootgestel word aan stres toestande en nie primer deur opbergingsregimes nie. Masters 2021-12-06T09:32:29Z 2021-12-22T14:29:13Z 2021-12-06T09:32:29Z 2021-12-22T14:29:13Z 2021-12 Thesis http://hdl.handle.net/10019.1/123921 en_ZA Stellenbosch University 168 pages : illustrations (some color) application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Apples (Braeburn) -- Breeding Apples (Braeburn) -- Quality Apples -- Storage -- Diseases and injuries Apples -- Effect of cold on Lenticel breakdown Fruit -- Storage -- Cooling UCTD Mzize, Nolubabalo Quantifying the role of vapour pressure deficit in the development of lenticel breakdown in ‘Braeburn’ apple |
| title | Quantifying the role of vapour pressure deficit in the development of lenticel breakdown in ‘Braeburn’ apple |
| title_full | Quantifying the role of vapour pressure deficit in the development of lenticel breakdown in ‘Braeburn’ apple |
| title_fullStr | Quantifying the role of vapour pressure deficit in the development of lenticel breakdown in ‘Braeburn’ apple |
| title_full_unstemmed | Quantifying the role of vapour pressure deficit in the development of lenticel breakdown in ‘Braeburn’ apple |
| title_short | Quantifying the role of vapour pressure deficit in the development of lenticel breakdown in ‘Braeburn’ apple |
| title_sort | quantifying the role of vapour pressure deficit in the development of lenticel breakdown in braeburn apple |
| topic | Apples (Braeburn) -- Breeding Apples (Braeburn) -- Quality Apples -- Storage -- Diseases and injuries Apples -- Effect of cold on Lenticel breakdown Fruit -- Storage -- Cooling UCTD |
| url | http://hdl.handle.net/10019.1/123921 |
| work_keys_str_mv | AT mzizenolubabalo quantifyingtheroleofvapourpressuredeficitinthedevelopmentoflenticelbreakdowninbraeburnapple |