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Assessment of pollen-mediated gene flow in wheat (Triticum aestivum L.) and related species
Thesis (MScAgric)--Stellenbosch University, 2025.
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| Format: | Thesis |
| Language: | English |
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Stellenbosch : Stellenbosch University
2025
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| _version_ | 1867613901716193280 |
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| access_status_str | Open Access |
| author | Van der Hoven, Madeleine Anne |
| author2 | Botes, Willem |
| author_browse | Botes, Willem Van der Hoven, Madeleine Anne |
| author_facet | Botes, Willem Van der Hoven, Madeleine Anne |
| author_sort | Van der Hoven, Madeleine Anne |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description | Thesis (MScAgric)--Stellenbosch University, 2025. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/132376 |
| institution | Stellenbosch University (South Africa) |
| language | English |
| last_indexed | 2026-06-10T12:43:30.888Z |
| 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:10019.1/132376 Assessment of pollen-mediated gene flow in wheat (Triticum aestivum L.) and related species Van der Hoven, Madeleine Anne Botes, Willem Hess, Lezaan Stellenbosch University. Faculty of AgriSciences. Dept. of Genetics & Institute of Plant Biotechnology. Wheat -- Genetic engineering Transgenic plants Wheat -- Pollen Wheat -- Breeding -- South Africa -- Western Cape Pollen-mediated gene flow Genetic transformation -- Data processing UCTD Thesis (MScAgric)--Stellenbosch University, 2025. van der Hoven, M. A. 2025. Assessment of pollen-mediated gene flow in wheat (Triticum aestivum L.) and related species. Unpublished masters thesis. Stellenbosch: Stellenbosch University [online]. Available: https://scholar.sun.ac.za/items/62645f0c-3a38-4f34-8bf5-553211b721b2 ENGLISH ABSTRACT: Growing demand for cereal crops is predicted to steer wheat production toward the exploitation of crop wild relatives and improvement by gene editing technologies. Interspecific crosses, biodiversity conservation, and seed purity are governed by pollen-mediated gene flow. The aim of this study was to obtain and assess pollen-mediated gene flow data to determine the possibility of outcrossing over a range of physical and phylogenetic distances. A field trial at Mariendahl experimental station, Stellenbosch, South Africa, was planted with two wheat and two triticale cultivars in a Nelder wheel layout. Eight receptor arms of 16 blocks, each with ten rows of wheat and ten rows of triticale, surrounded a central pollen donor block containing alternative cultivars of both crops. The receptor arms were orientated according to the cardinal and inter-cardinal wind directions, and the blocks extended across 51.4 m from the edge of the central pollen donor block. The trial covered 1.08 ha within the total planted area of 1.43 ha. Throughout the trial, weather data was recorded. The wheat and triticale material were harvested at the end of the growing season, and seed phenotypes were recorded using the SeedCounter application available on Android. Harvested seed (F1 generation) was then germinated at Welgevallen experimental station, Stellenbosch, South Africa and deoxyribonucleic acid was extracted for molecular analysis. After several optimisation attempts, none of the 41 simple sequence repeat markers tested could be used to determine outcrossing in the F1 triticale because of genetic similarity. However, five simple sequence repeat markers tested could be used to determine outcrossing in the F1 wheat. A greenhouse crossability trial was concurrently planted to establish baseline crossability in wide hybridisations of wheat wild relatives and a wheat advanced breeding line from the Stellenbosch University Plant Breeding Laboratory. The advanced breeding line was emasculated and pollinated using pollen from the wheat wild relatives. Seed set and germination were recorded. High levels of hybridisation were recorded in both trials (field and greenhouse), with outcrossing observed at the periphery of the field trial, and most crosses in the greenhouse resulted in successful fertilisation, seed set and germination. The results of the field trial demonstrated the effect that wind as a vector has on pollen-mediated gene flow, where the South-East receptor arm recorded the highest wind speeds during dawn and dusk and the highest outcrossing percentage (51.59%). Seed phenotype was greatly impacted by plant stress and was thus a less effective tool for pollen-mediated gene flow identification. Flowering synchrony caused outcrossing percentages and phenotypic traits to trend similarly across rows despite the influence of stress. Current growing guidelines, therefore, do not accurately reflect the outcrossing ability of wheat and related species. Furthermore, while crop wild relatives can contribute to wheat improvements, the crossability poses a threat to natural biodiversity. Highest crossability was recorded between wild relatives most genetically similar to cultivated wheat (28.23% and 18.39%) and lowest between those more distantly related (0.33% and 1.33%), validating existing knowledge. Moreover, to variable extents, all parental combinations showed crossability with viable seed set. AFRIKAANSE OPSOMMING: Die groeiende aanvraag na graangewasse word voorspel om die produksie van koring te lei na die benutting van wilde gewas-verwantes en verbetering deur middel van geenredigeringstegnologieë. Interspesifieke-kruising, biodiversiteitsbehoud en saadsuiwerheid word beheer deur stuifmeel-gemediëerde geenvloei (SGGV). Die doel van hierdie studie was om SGGV-data te bekom en te evalueer om die vermoë van kruisbestuiwing oor 'n reeks fisiese en filogenetiese afstande te bepaal. ‘n Veldproef by die Mariendahl eksperimentele stasie, Stellenbosch, Suid-Afrika, is aangeplant met twee koring- en twee triticale-variëteite in 'n Nelder-wielopstelling. Agt ontvangerarms, wat uit 16 blokke bestaan, elk met tien rye koring en tien rye triticale, het 'n sentrale stuifmeel-donorblok omring wat alternatiewe variëteite van beide gewasse beva het. Die ontvangerarms is georiënteer volgens die kardinale en inter-kardinale windrigtings, en die blokke het 51.4 m van die rand van die sentrale stuifmeel-donorblok gestrek. Die proef het 1.08 ha van die totale aangeplante area van 1.43 ha beslaan. Gedurende die proef is weerdata aangeteken. Die koring- en triticale-materiaal is aan die einde van die groeiseisoen geoes, en saad fenotipes is bepaal met behulp van die SeedCounter-toepassing wat beskikbaar is op Android. Geoeste saad (F1-generasie) is toe by die Welgevallen eksperimentele stasie, Stellenbosch, Suid-Afrika ontkiem en deoksiribonukleïensuur is vir molekulêre analise geekstraeer. Na verskeie optimisering pogings, kon geen van die 41 eenvoudige volgorde herhalings (SSR) merkers wat getoets is, gebruik word om kruisbestuiwing in die F1 triticale te bepaal nie weens genetiese similariteit. Vyf SSR-merkers wat getoets is, kon egter gebruik word om kruisbestuiwing in die F1-koring te bepaal. 'n Glashuis gebaseerde kruisbaarheidproef is gelyktydig aangeplant om basislyn kruisbaarheid in breë hibridisasies van koring se wilde verwantes en 'n gevorderde koringteellyn van die Stellenbosch Universiteit Planteteelt Laboratorium te bepaal. Die gevorderde teellyn is ontman en bestuiwings is uitgevoer met stuifmeel van die wilde verwantes. Saadontwikkeling en daaropvolgende ontkieming is vervolgens aangeteken. Hoë vlakke van hibridisasie is in beide proewe (veld en glashuis) waargeneem, met kruisbestuiwing wat aan die rand van die veldproef waargeneem is, en die meeste kruisings in die glashuis het gelei tot suksesvolle bevrugting, saadontwikkeling en ontkieming. Die resultate van die veldproef het die effek getoon wat wind as 'n stuifmeelvektor op stuifmeel-gemediëerde geenvloei het, waar die Suidoos-ontvangerarm die hoogste windsnelhede tydens dagbreek en skemering geregistreer het en die hoogste kruisbestuwing persentasie (51.59%) getoon het. Saadfenotipe is beïnvloed deur plantstres en was dus 'n minder effektiewe hulpmiddel vir identifikasie van SGGV. Blom sinkronisasie het kruisbestuiwing persentasies en fenotipiese eienskappe teweeggebring wat soortgelyk oor rye neig, ten spyte van die invloed van stres. Huidige groei riglyne reflekteer dus nie akkuraat die kruisbestuwingsvermoë van koring en verwante spesies nie. Verder, terwyl wilde verwantes tot die verbetering van koring kan bydra, stel die kruisbaarheid 'n bedreiging vir natuurlike biodiversiteit in. Die hoogste vlakke van kruisbaarheid is tussen wilde verwantes wat geneties die naaste aan verboude koring is (28.23% en 18.39%) en die laagste tussen dié wat verder verwant is (0.33% en 1.33%), wat bestaande kennis bevestig. Boonop het alle ouerkombinasies, tot verskillende grade, kruisbaarheid met lewensvatbare saadontwikkeling getoon. Masters 2025-06-05T09:14:47Z 2025-06-05T09:14:47Z 2025-03 Thesis https://scholar.sun.ac.za/handle/10019.1/132376 en Stellenbosch University xii, 7 unnumbered pages, 101 pages : illustrations application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Wheat -- Genetic engineering Transgenic plants Wheat -- Pollen Wheat -- Breeding -- South Africa -- Western Cape Pollen-mediated gene flow Genetic transformation -- Data processing UCTD Van der Hoven, Madeleine Anne Assessment of pollen-mediated gene flow in wheat (Triticum aestivum L.) and related species |
| title | Assessment of pollen-mediated gene flow in wheat (Triticum aestivum L.) and related species |
| title_full | Assessment of pollen-mediated gene flow in wheat (Triticum aestivum L.) and related species |
| title_fullStr | Assessment of pollen-mediated gene flow in wheat (Triticum aestivum L.) and related species |
| title_full_unstemmed | Assessment of pollen-mediated gene flow in wheat (Triticum aestivum L.) and related species |
| title_short | Assessment of pollen-mediated gene flow in wheat (Triticum aestivum L.) and related species |
| title_sort | assessment of pollen mediated gene flow in wheat triticum aestivum l and related species |
| topic | Wheat -- Genetic engineering Transgenic plants Wheat -- Pollen Wheat -- Breeding -- South Africa -- Western Cape Pollen-mediated gene flow Genetic transformation -- Data processing UCTD |
| url | https://scholar.sun.ac.za/handle/10019.1/132376 |
| work_keys_str_mv | AT vanderhovenmadeleineanne assessmentofpollenmediatedgeneflowinwheattriticumaestivumlandrelatedspecies |