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Inducing mutations in bread wheat (Triticum aestivum L.) using chemical treatments
Thesis (MSc)--Stellenbosch University, 2014.
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Stellenbosch : Stellenbosch University
2015
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| _version_ | 1867613818687848449 |
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| access_status_str | Open Access |
| author | Mbwanji, Kenneth |
| author2 | Botha-Oberholster, Anna-Maria |
| author_browse | Botha-Oberholster, Anna-Maria Mbwanji, Kenneth |
| author_facet | Botha-Oberholster, Anna-Maria Mbwanji, Kenneth |
| author_sort | Mbwanji, Kenneth |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description | Thesis (MSc)--Stellenbosch University, 2014. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/95781 |
| institution | Stellenbosch University (South Africa) |
| language | en_ZA |
| last_indexed | 2026-06-10T12:42:11.774Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2015 |
| publishDateRange | 2015 |
| publishDateSort | 2015 |
| publisher | Stellenbosch : Stellenbosch University |
| publisherStr | Stellenbosch : Stellenbosch University |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/95781 Inducing mutations in bread wheat (Triticum aestivum L.) using chemical treatments Mbwanji, Kenneth Botha-Oberholster, Anna-Maria Stellenbosch University. Faculty of AgriSciences. Dept. of Genetics. Chemical induced mutagenesis Bread wheat (Triticum aestivum L.) Drought tolerance in wheat UCTD Thesis (MSc)--Stellenbosch University, 2014. ENGLISH ABSTRACT: Bread wheat (Triticum aestivum L.) production is hindered by a variety of abiotic stresses with drought being the most devastating. Mutation breeding through induced mutagenesis is one way for wheat breeders to adapt to the challenges posed by climate change. Especially, chemically induced mutagenesis showed promise in improving drought tolerance using different recommended mutagens at optimum concentrations and treatment durations. The aim of the study was to improve drought tolerance in wheat by means of chemical induced mutagenesis. In the study, the mutagenic properties of four chemicals, namely Sodium azide (SA, 0.1 mM, 1.0 mM and 10 mM), Ethyl methanesulfonate (EMS, 0.1%, 0.5%, 1.0% v/v), Maleic hydrazide (MH, 0.5 mM, 1.0 mM, 2.0 mM), and N-methyl-N-nitrosourea (MNU, 0.5 mM, 1.0 mM, 2.0 mM) at different concentrations and treatment durations (2h, 4h and 8h) were compared. To select for mutants that express drought tolerance, the M1 plants were exposed to water stress. NMU and MH treated M1 plants demonstrated zero survival rates, while a few of the plants treated with SA and EMS survived. In the study, treatments with 0.5% (EMS) 4h, 1% (EMS) 2h, 1 mM (SA) 2h and 1 mM (SA) 8h were considered optimum, since these treatments resulted in fertile plants. However, the chemically derived mutant wheat lines displayed a lower germination rate, delayed maturity, stunted growth and lower than average seed mass when compared to the control. The latter traits were also verified in the M2 and M3 generations. The M2 and M3 generations also displayed a shorter growth form and delayed maturity phenotype, but had higher germination rates and produced more seeds. Screening for drought tolerance conducted on the M3 plants confirmed the tolerant phenotype found in the M1 generation plants. Amplified fragment length polymorphism (AFLP) profiling was also conducted on the mutants using three primer combinations (MTT/ECG, MTG/ECT and MTG/EGC) in order to assess the extent and significance of the induced mutations. From the obtained data, it was revealed that SA 1 mM (2h) 16 had the highest number of induced total character differences (109) relative to the control of all the SA and EMS derived mutants, suggesting that a treatment with 1 mM SA for 2h induced more mutations than any other SA or any of the EMS treatments. Of the sequenced clones, only one revealed similarity to a T. aestivum isolate AAC/CTG7 scab resistance-linked AFLP fragment gene sequence, an important disease of wheat, but due to time constrains this finding was not investigated further. AFRIKAANSE OPSOMMING: Die produksie van broodkoring (Triticum aestivum L.) word deur ‘n aantal abiotiese stressors beperk, met droogte die een met die grootste impak. Mutasie-teling deur middel van geïnduseerde mutagenese is ‘n manier waardeur koringtelers die uitdagings van klimaatsveranderinge kan oorbrug. Veral chemies-geïnduseerde mutagenese vertoon belofte vir die verbetering van droogte-toleransie deur middel van die gebruik van verskillende aanbevole mutagene teen optimale konsentrasies en blootstellings tye. Dus, die doel van die studie was om droogte-toleransie in koring deur middel van chemies-geïnduseerde mutagenese te bewerkstellig. In die studie is vier chemikalië teen verskillende konsentrasies dit is Natriumasied (SA, 0.1 mM, 1.0 mM and 10 mM), Etielmetaansulfonaat (EMS, 0.1%, 0.5%, 1.0% v/v), Malaathidrasied (MH, 0.5 mM, 1.0 mM, 2.0 mM), and N-metiel-N-nitrosourea (MNU, 0.5 mM, 1.0 mM, 2.0 mM) en blootstellings tye (2h, 4h en 8h) vergelyk. Om vir droogte-toleransie in die M1 plante te selekteer, is hierdie plante aan waterstres-toestande blootgestel. NMU- en MH-behandelde M1- plante het geen toleransie vertoon nie, aangesien alle plante gevrek het, terwyl SA- en EMSbehandelde plante oorleef het. In die studie het behandelings met 0.5% (EMS) 4h, 1% (EMS) 2h, 1 mM (SA) 2h en 1 mM (SA) 8h vrugbare plante gelewer en is as optimaal beskou. Die chemies-geïnduseerde mutante het egter ‘n laer kiemkragtigheid, vetraagde volwassewording, korter groeivorm en laer gemidddelde saadproduksie vertoon. Hierdie eienskappe is ook in die M2- en M3-generasies beoordeel. Die M2- en M3-generasies het ook die kort groeivorm en verlengde volwassewording vertoon, maar het meer kiemkragtigheid en ‘n groter saadproduksie vertoon. Droogte-toleransie wat by die M3-plante geëvalueer is, het die toleransie wat in die M1- generasie plante bevind is, bevestig. Geamplifiseerde fragment lengte polimorfisme (AFLP)- profiele is ook met drie inleier-kombinasies (MTT/ECG, MTG/ECT and MTG/EGC) op die mutante gedoen, en die mate en belangrikheid (indien enige) van die chemies-geïnduseerde mutasies, is gekwantifiseer. Vanuit die data kon afgelei word dat SA 1 mM (2h) 16 die meeste totale aantal karakter verskille (109) van alle SA en EMS-behandellinge, relatief tot die kontrole tot gevolg gehad het, wat aandui dat hierdie behandeling die meeste mutasies geïnduseer het. Van die klone, waarvan die basisvolgorde bepaal was, het slegs ee ooreenkoms aan ‘n T. aestivum isolaat AAC/CTG7 scab weerstand-gekoppelde AFLP-fragment geenvolgorde vertoon. Scab is ‘n belangrike siekte van koring, maar as gevolg van ‘n tydbeperking kon hierdie bevinding nie verder ondersoek word nie. Masters 2015-01-13T11:46:54Z 2016-01-01T03:00:15Z 2014-12 Thesis http://hdl.handle.net/10019.1/95781 en_ZA Stellenbosch University 126 pages : illustrations application/pdf application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Chemical induced mutagenesis Bread wheat (Triticum aestivum L.) Drought tolerance in wheat UCTD Mbwanji, Kenneth Inducing mutations in bread wheat (Triticum aestivum L.) using chemical treatments |
| title | Inducing mutations in bread wheat (Triticum aestivum L.) using chemical treatments |
| title_full | Inducing mutations in bread wheat (Triticum aestivum L.) using chemical treatments |
| title_fullStr | Inducing mutations in bread wheat (Triticum aestivum L.) using chemical treatments |
| title_full_unstemmed | Inducing mutations in bread wheat (Triticum aestivum L.) using chemical treatments |
| title_short | Inducing mutations in bread wheat (Triticum aestivum L.) using chemical treatments |
| title_sort | inducing mutations in bread wheat triticum aestivum l using chemical treatments |
| topic | Chemical induced mutagenesis Bread wheat (Triticum aestivum L.) Drought tolerance in wheat UCTD |
| url | http://hdl.handle.net/10019.1/95781 |
| work_keys_str_mv | AT mbwanjikenneth inducingmutationsinbreadwheattriticumaestivumlusingchemicaltreatments |