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Development of a pre-selection index for cider apple (Malus x domestica Borkh.) genotypes by phenotyping a low-chill requiring red-fleshed breeding progeny
Thesis (MScAgric)--Stellenbosch University, 2025.
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Stellenbosch : Stellenbosch University
2025
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| _version_ | 1867614106470580224 |
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| access_status_str | Open Access |
| author | Aucamp, Armand |
| author2 | Louw, Esme D.
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| author_browse | Aucamp, Armand Louw, Esme D. |
| author_facet | Louw, Esme D.
Aucamp, Armand |
| author_sort | Aucamp, Armand |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description | Thesis (MScAgric)--Stellenbosch University, 2025. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/132053 |
| institution | Stellenbosch University (South Africa) |
| last_indexed | 2026-06-10T12:46:45.739Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2025 |
| publishDateRange | 2025 |
| publishDateSort | 2025 |
| publisher | Stellenbosch : Stellenbosch University |
| publisherStr | Stellenbosch : Stellenbosch University |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/132053 Development of a pre-selection index for cider apple (Malus x domestica Borkh.) genotypes by phenotyping a low-chill requiring red-fleshed breeding progeny Aucamp, Armand Louw, Esme D. Labuschagne, Iwan De Beer, Dalene Marais, Jeannine Stellenbosch University. Faculty of AgriSciences. Dept. of Horticultural Science. Cider industry -- South Africa Apples -- Genetic engineering -- Environmental aspects Genotype-environment interaction Thesis (MScAgric)--Stellenbosch University, 2025. Aucamp, A. 2025. Development of a pre-selection index for cider apple (Malus x domestica Borkh.) genotypes by phenotyping a low-chill requiring red-fleshed breeding progeny. Unpublished masters thesis. Stellenbosch: Stellenbosch Univeristy [online]. Available: https://scholar.sun.ac.za/items/e49bac8d-f5a0-4e2e-8983-6530b8c1d8ee ENGLISH ABSTRACT: The rapid growth of the cider industry in South Africa, coupled with wine grape producers in warmer regions seeking diversification options, led to the concept of developing low-chill, red-fleshed cider apples to support both industries. The low-chill trait allows apples to be cultivated in warmer areas traditionally associated with wine grape production, while the red-fleshed characteristic offers novelty to the final product by adding red colouration and enhancing fruit quality traits associated with cider-making suitability. This innovation could lead to the creation of a unique red cider product. To achieve this, a cross was made between ‘Anna’ (a low-chill genotype) and ‘Geneva’ (a red-fleshed genotype). The progeny was screened for red leaf colouration, an indicator of Type 1 red-fleshed apples, allowing the selection and planting of only red-fleshed genotypes. These selected genotypes with red foliage were grafted onto M.7 rootstocks and planted in a low-chill environment. Since traditional breeding processes are time-consuming, the phenotypic variation within this progeny for reproductive, vegetative and fruit quality was quantified to establish a pre-selection index that could accelerate the development of low-chill, red-fleshed cider apple genotypes. The index was constructed by identifying the best-performing genotypes based on traits related to reproduction, vegetative growth, and fruit quality, serving as a baseline for comparison. A random decision forest model was employed to assign importance to these traits, and in conjunction with the baseline, a pre-selection index was developed to identify promising genotypes. The sensory attributes and biochemical composition of this unique low-chill, red-fleshed progeny were also analysed. The indexing results suggested that sweet cider production is the most viable outcome, as most top-performing genotypes were classified as sweet cider apples, which aligned well with the South African market’s preference for sweeter products. Among the progeny, Genotype 10 showed exceptional potential as a low-chill, red-fleshed sweet cider apple. Several other genotypes were also identified as viable options for cultivation in warmer areas, with additional future crosses recommended to further advance the development of low-chill, red-fleshed apples. Sensory analyses on apple juice revealed that the selected genotypes displayed sweet berry and fruity flavours, complemented by varying levels of bitterness and astringency. Notably, Genotype 100 demonstrated a biochemical composition that could enable colour retention and stability during processing, making it invaluable in the development of a red cider product. Grounded in horticulture and genetics, this thesis lays the framework for identifying low-chill, red-fleshed cider apple genotypes suitable for production in non-traditional apple-growing regions, addressing the needs of both producers and the cider industry. AFRIKAANSE OPSOMMING: Die drastiese groei van die appelwynbedryf in Suid-Afrika, tesame met wynprodusente in warmer streke wat diversifikasie-opsies soek, het gelei tot die konsep om lae-koue behoefte, rooi-vleis appels te ontwikkel om beide bedrywe te ondersteun. Die lae-koue behoefte eienskap maak dit moontlik om appels te verbou in warmer gebiede wat tradisioneel met wyndruifproduksie geassosieer word, terwyl die rooi-vleis kenmerk unieke kleur aan die appelwyn bied. Rooi-vleis appels het ook vrugkwaliteitseienskappe wat die appelwynkwaliteit verbeter. Hierdie innovasie kan lei tot die skepping van 'n unieke rooi appelwynproduk. Om dit te bereik is 'n kruising gemaak tussen ‘Anna’ (lae-koue behoeft genotipe) en ‘Geneva’ (rooi-vleis genotipe). Die nageslag is geselekteer vir rooi blaarkleur wat 'n aanduiding is van Tipe 1 rooi-vleis appels. Dit het die seleksie en aanplanting van slegs rooi-vleis appel genotipes moontlik gemaak. Hierdie genotipe is op M.7 onderstamme geënt en in 'n lae-koue behoefte omgewing geplant. Aangesien tradisionele telingsprosesse tydrowend is, is die fenotipiese variasie gekwantifiseer om 'n voorseleksie-indeks op te stel wat die ontwikkeling van lae-koue behoefte, rooi-vleis appels kan versnel. Die indeks is saamgestel deur die beste presterende genotipes te identifiseer op grond van reproduktiewe ontwikkeling, vegetatiewe groei en vrugkwaliteit, wat as basislyn vir vergelyking gedien het. 'n Willekeurige besluitbosmodel ('random decision forest model') is gebruik om belangrikheid aan hierdie eienskappe toe te ken, en in samewerking met die basislyn is 'n voorseleksie-indeks ontwikkel om belowende genotiepes te identifiseer. Die sensoriese eienskappe en biochemiese samestelling van hierdie rooi-vleis appel nageslag is ook ontleed. Die indekseringsresultate het voorgestel dat die produksie van soet appelwyn die mees haalbare uitkoms is, aangesien die meeste top presterende genotipes as soet appelwyn appels geklassifiseer is, wat ooreenstem met die Suid-Afrikaanse mark se voorkeur vir soeter produkte. Genotipe 10 het buitengewone potensiaal getoon as 'n lae-koue behoefte, rooi-vleis appel vir soet appelwyn. Ander genotipes is ook geïdentifiseer as moontlike opsies vir verbouing in warmer gebiede, en toekomstige kruisings is aanbeveel om die ontwikkeling van lae-koue behoefte, rooi-vleis appels verder te bevorder. Sensoriese ontledings het soet bessie- en vruggeure vertoon, aangevul met verskillende vlakke van bitterheid en frankheid. Veral genotipe 100 het ‘n biochemiese samestelling vertoon wat kleurbehoud en stabiliteit tydens verwerking moontlik kan maak, wat dit van onskatbare waarde maak vir rooi appelwyn produksie. Gesteun in hortologie en genetika, lê hierdie tesis die raamwerk vir die identifisering van lae- koue behoefte, rooi-vleis appelwyn appels geskik vir produksie in nie-tradisionele appelstreke, en spreek sodoende die behoeftes van beide produsente en die appelwynbedryf aan. Masters 2025-05-21T09:43:34Z 2025-05-21T09:43:34Z 2025-03 Thesis https://scholar.sun.ac.za/handle/10019.1/132053 Stellenbosch University vi, 333 pages : illustrations (some color) application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Cider industry -- South Africa Apples -- Genetic engineering -- Environmental aspects Genotype-environment interaction Aucamp, Armand Development of a pre-selection index for cider apple (Malus x domestica Borkh.) genotypes by phenotyping a low-chill requiring red-fleshed breeding progeny |
| title | Development of a pre-selection index for cider apple (Malus x domestica Borkh.) genotypes by phenotyping a low-chill requiring red-fleshed breeding progeny |
| title_full | Development of a pre-selection index for cider apple (Malus x domestica Borkh.) genotypes by phenotyping a low-chill requiring red-fleshed breeding progeny |
| title_fullStr | Development of a pre-selection index for cider apple (Malus x domestica Borkh.) genotypes by phenotyping a low-chill requiring red-fleshed breeding progeny |
| title_full_unstemmed | Development of a pre-selection index for cider apple (Malus x domestica Borkh.) genotypes by phenotyping a low-chill requiring red-fleshed breeding progeny |
| title_short | Development of a pre-selection index for cider apple (Malus x domestica Borkh.) genotypes by phenotyping a low-chill requiring red-fleshed breeding progeny |
| title_sort | development of a pre selection index for cider apple malus x domestica borkh genotypes by phenotyping a low chill requiring red fleshed breeding progeny |
| topic | Cider industry -- South Africa Apples -- Genetic engineering -- Environmental aspects Genotype-environment interaction |
| url | https://scholar.sun.ac.za/handle/10019.1/132053 |
| work_keys_str_mv | AT aucamparmand developmentofapreselectionindexforciderapplemalusxdomesticaborkhgenotypesbyphenotypingalowchillrequiringredfleshedbreedingprogeny |