Rust and FHB improvement of wheat through marker assisted selection and phenotyping
| dc.contributor.advisor | Botes, Willem | en_ZA |
| dc.contributor.advisor | Rose, Lindy J. | en_ZA |
| dc.contributor.author | De Wet, Sumari | en_ZA |
| dc.contributor.other | Stellenbosch University. Faculty of AgriSciences. Dept. of Genetics. | en_ZA |
| dc.date.accessioned | 2021-12-06T06:45:56Z | |
| dc.date.accessioned | 2021-12-22T14:30:15Z | |
| dc.date.available | 2021-12-06T06:45:56Z | |
| dc.date.available | 2021-12-22T14:30:15Z | |
| dc.date.issued | 2021-12 | |
| dc.description | Thesis (MScAgric)--Stellenbosch University, 2021. | en_ZA |
| dc.description.abstract | ENGLISH ABSTRACT: Wheat is one of the most widely cultivated crops of significant economic and nutritional importance. The predicted growth of the human population will result in higher food demands in the future. Wheat yield needs to sustainably increase to maintain food security. Unfortunately, the productivity of wheat are negatively impacted by abiotic and biotic stressors. Rust (leaf, stem and stripe) are the most prevalent disease on wheat that can cause severe damage to global production. Wheat rusts are caused by Puccinia spp. that are widely spread and highly adaptable. Fusarium head blight (FHB) on wheat is caused by Fusarium species that forms a complex that can produce mycotoxins in infected seeds. The FHB disease on wheat can result in reduction of seed quality and yield. One of the most important management factors to solve the problems posed by rust and FHB is by breeding for host plant resistance. Genetic resistance can be improved by using different rust and FHB resistance sources to achieve durable resistance. The aim of this study was to generate molecular and phenotypic data of wheat lines to evaluate resistance to rust and FHB for improvement of genetic resistant material. An existing male sterile segregating MS-MARS population together with donor populations were screened for markers linked to rust and FHB resistance. Wheat lines that contained desirable traits were selected as parents in two breeding cycles of the male sterile mediated marker-assisted recurrent selection (MS-MARS) pre-breeding program. The donor lines were further evaluated by rust field phenotyping and FHB phenotyping under glasshouse conditions. The molecular markers were successfully implemented to molecular characterise the populations and assisted in the parent selection process. The frequencies of two important slow rusting genes, Sr2 and Lr34, were increased by 1.67% and 10.00%. The crossing cycles produced a large number of 3919 (cycle 1) and 9716 (cycle 2) hybrid seeds. Rust field evaluations enabled identifying wheat lines that showed low susceptible phenotypic responses (20S to 40S) to leaf rust disease. Successful inoculations with Fusarium graminearum isolates were performed and disease severity between 13% and 100% were measured on 21 days post inoculation. The liquid chromatography tandem mass spectrometry (LC-MS/MS) technique detected deoxynivalenol (DON) contamination levels above 0.032 ppb in fourteen wheat samples. Future studies should aim at screening germplasms for the presence of more molecular markers linked to rust and FHB resistance. Selection of breeding parents should be based on both molecular data as well as phenotype data collected over multiple wheat growing seasons to improve effectiveness of resistance breeding. | en_ZA |
| dc.description.abstract | AFRIKAANSE OPSOMMING: Koring is een van die mees wyd gekultiveerde gewasse wat belangrike ekonomiese en voedselwaarde het. Daar word voorspel dat die menslike populasie sal aanhou groei, wat sal lei tot verhoogde voedselbehoeftes in die toekoms. Koring opbrengste sal toenemend moet styg om voedselsekuriteit te verseker. Koring opbrengste word negatief beïnvloed deur biotiese en abiotiese stresfaktore. Roes (blaar, stam en streep) is een van die algemeenste siektes wat voorkom op koring en veroorsaak groot verliese aan wêreldwye produksie. Roes op koring word veroorsaak deur Puccinia spesies wat wyd verspreid voorkom en hoogs aanpasbaar is. Fusarium head blight (FHB) op koring word veroorsaak deur Fusarium spesies wat ‘n kompleks vorm en die vermoë het om mikotoksiene te produseer in geïnfekteerde sade. Koringteling vir weerstand teen roes en FHB is ‘n belangrike strategie om opbrengste te verhoog. Genetiese weerstand kan verbeter word deur verskillende roes en FHB weerstandsbronne te gebruik om duursame weerstand te bekom. Die doel van die studie was om molekulêre en phenotipiese data van koringlyne te versamel om genetiese weerstand teenoor roes en FHB te evalueer en te verbeter. ‘n Populasie wat ontstaan het deur manlik steriele segregerende merker assisterend herhalende seleksie (MS-MARS), tesame met skenker populasies was ondersoek vir die teenwoordigheid van merkers wat geassosieer is met roes en FHB weerstand. Koringlyne, wat wenslike eienskappe besit, was gekies as ouers in twee telingsiklusse wat deel gevorm het van die MS-MARS voortelingsskema. Die skenkerlyne was verder ge-evalueer in ‘n roes phenotipering veldproef en FHB phenotipering glashuisproewe. Die molekulêre merkers was suksesvol geïmplementeer om die populasies molekulêr te karakteriseer en het bygedra tot die ouer seleksie proses. Die geen frekwensies van die belangrike roesgene, Sr2 en Lr34, het verhoog met 1.67% en 10.00%. Die kruising siklusse het ‘n groot aantal hibried sade van 3919 (siklus 1) en 9716 (siklus 2) geproduseer. Evaluasies van roes in die veld het dit moontlik gemaak om koringlyne te identifiseer wat lae vatbare phenotipiese reaksies (20S tot 40S) getoon het teenoor blaarroes. Suksesvolle inokulasies met Fusarium graminearum isolate het plaasgevind en siekte ernstigheidsgrade van tussen 13% en 100%, was aangeteken op 21 dae na inokulasie. Die ‘liquid chromatography tandem mass spectrometry’ (LCMS/ MS) tegniek was gebruik om deoxynivalenol (DON) kontaminasie vlakke bo 0.032 ppb te meet in 14 koringmonsters. Die aantal molekulêre merkers wat geassosieer is met roes en FHB weerstand moet vermeerder word wanneer kiemplasmas in toekomstige studies ge-evalueer word. Seleksie en teling van ouers moet gebasseer word op beide molekulêre en phenotipiese data wat versamel word oor verskeie koring groeiseisoene om die effek van weerstandteling te verbeter. | af_ZA |
| dc.description.version | Masters | en_ZA |
| dc.format.extent | xix, 186 pages : illustrations (some color), maps | en_ZA |
| dc.identifier.uri | http://hdl.handle.net/10019.1/123938 | |
| dc.language.iso | en_ZA | en_ZA |
| dc.publisher | Stellenbosch : Stellenbosch University | en_ZA |
| dc.rights.holder | Stellenbosch University | en_ZA |
| dc.subject | Wheat -- Breeding | en_ZA |
| dc.subject | Wheat fusarium culmorum head blight -- Genetic aspects | en_ZA |
| dc.subject | Rust diseases | af_ZA |
| dc.subject | Phenotype -- Environmental aspects | en_ZA |
| dc.subject | Wheat -- Disease and pest resistance | en_ZA |
| dc.subject | UCTD | en_ZA |
| dc.title | Rust and FHB improvement of wheat through marker assisted selection and phenotyping | en_ZA |
| dc.type | Thesis | en_ZA |