The manipulation of soil microbial composition for banana fusarium wilt management
| dc.contributor.advisor | Viljoen, Altus | en_ZA |
| dc.contributor.advisor | Mostert, D. | en_ZA |
| dc.contributor.author | Cyster, Amore | en_ZA |
| dc.contributor.other | Stellenbosch University. Faculty of AgriSciences. Dept. of Plant Pathology. | en_ZA |
| dc.date.accessioned | 2021-05-24T11:27:49Z | |
| dc.date.available | 2022-09-30T03:00:11Z | |
| dc.date.issued | 2021-03 | |
| dc.description | Thesis (MScAgric)--Stellenbosch University, 2021. | en_ZA |
| dc.description.abstract | ENGLISH ABSTRACT: Banana (Musa sp.) is an important food security crop especially in developing countries. Most of bananas are cultivated for local consumption and only 15% of the total banana production is traded in the international market. Approximately 50 billion tonnes of Cavendish bananas are produced globally every year. A major constrain to banana production is Fusarium wilt, which is caused by the soil- borne fungus Fusarium oxysporum f. sp. cubense (Foc). Different races of the pathogen are identified based on pathogenicity to reference host cultivars. Race 1 and Race 2 cause disease on Gros Michel and some cooking bananas like Bluggoe. Race 4 is further divided into subtropical (STR4) and tropical (TR4) and affects Cavendish and most banana cultivars susceptible to Race 1 and 2 in the subtropical and tropical regions, respectively. As mentioned, Foc is a soilborne fungus that produce thick-walled survival spores called chlamydospores. These spores are resilient in unfavourable environmental conditions and may survive in soil for more than 20 years. Once Foc is infested in a plantation, it is extremely difficult to eradicate. The only option to continue with production is to plant resistant varieties. Partially resistant somaclonal Cavendish variants to TR4 have been developed but resistance lowers as the crop cycle increases. Foc inoculum management plays a key role in this sense. The use of biological control agents for Fusarium wilt of banana have been studied for many years and reported positive results. The mode of action of biological control agents can either be direct (production of antibiotics, parasitism, or competition) or indirect (induced systemic resistance or plant growth promotion). In this study potential biological control candidates and their cell-free filtrates were investigated for its ability to suppress the growth of Foc STR4, TR4, Race 1 and Race 2 in vitro. Significant growth inhibition was reported in isolates identified as Bacillus spp. and Burkholderia sp. Greenhouse evaluations reported bacterial isolates identified as Bacillus spp, Pseudomonas sp. and Burkholderia sp. significantly reduced disease incidence and increased plant height when applied as a live cell cultures and as cell-free filtrates compared to untreated control. The use of soil amendments such as organic matter application, bio-fertilisers and urea can contribute to soil health and suppressiveness. In this study, five soil treatments were tested for their ability to suppress Foc STR4 disease and increase plant health when applied as a preventative or curative treatment. Urea, Vermicompost applied as curative treatment and Effective Microbes (EM) applied as curative treatment significantly reduced disease incidence compared to an untreated control. Urea treatment significantly decreased Foc STR4 spore counts in soil compared to an untreated control. Vermicompost significantly increased plant height and increased root mass. | en_ZA |
| dc.description.abstract | AFRIKAANSE OPSOMMING: Piesang (Musa sp.) is 'n belangrike gewas vir voedsel sekuriteit in ontwikkelende lande. Die meeste piesangs word vir plaaslike verbruik verbou en slegs 15% van die totale piesangproduksie word in die internasionale mark verhandel. Ongeveer 50 miljard ton Cavendish piesangs word jaarliks wêreldwyd geproduseer. 'n Belangrike beperking op die produksie van piesangs is Fusarium-verwelking, wat veroorsaak word deur die grond gedraagde swam Fusarium oxysporum f. sp. cubense (Foc). Die verskillende rasse van die patogeen word geïdentifiseer op grond van patogenisiteit op verskillende gasheer kultivars. Ras 1 en Ras 2 veroorsaak siektes op Gros Michel en sommige kookpiesangs soos Bluggoe. Ras 4word verder verdeel in subtropiese (STR4) en tropiese (TR4) en affekteer Cavendish en die meeste piesangkultivars wat onderskeidelik vatbaar is vir Ras 1 en 2, in die subtropiese en tropiese streke. Foc is produseer dikwandige oorlewingspore wat chlamydospore genoem wordwat kan langer as 20 jaar oorleef in ongunstige omgewingstoestande. Sodra Foc in 'n plantasie besmet is, is dit uiters moeilik omte beheer. Die enigste opsie om voort te gaan met die produksie is om weerstandbiedende variëteite te gebruik. Gedeeltelik weerstandige somaklonale Cavendish variëteite vir TR4 is ontwikkel, maar weerstand daal namate die gewassiklus toeneem. Foc inokulum bestuur speel dus 'n belangrike rol om produksie vir langer ekonomies te hou. Die gebruik van biologiese beheermiddels vir Fusarium verwelking van piesang is al lank bestudeer en positiewe resultate is aangeteken. Biologiese beheermiddels kan ‘n direkte (produksie van antibiotikas, parasitisme of kompetisie) of indirekte (geïnduseerde sistemiese weerstand of bevordering van plantgroei) effek op Foc hệ. Die effek van biologiese beheer kandidate en hul sel-vrye filtrate vir die vermoë om die groei van Foc STR4, TR4, Ras 1 en Ras 2 in vitro te onderdruk, is in hierdie studie ondersoek. Beduidende onderdrukking van Foc groei is rapporteer in isolate geïdentifiseer as Bacillus spp. en Burkholderia sp. Bakteriële isolate wat geïdentifiseer is as Bacillus spp, Pseudomonas sp. en Burkholderia sp. kon die voorkoms van Foc siekte aansienlik verminder en plant lengte vermeer toe dit toegedien was as 'n lewende selkultuur sowel as 'n sel-vrye filtraat onder glashuis kondisies wanneer dit vergelyk was met onbehandelde kontrole. Die gebruik van grondbehandelings soos organiese materiaal, bio-kunsmis en ureum kan bydra tot die gesondheid van die grond en onderdrukking van grondsiektes. In hierdie studie is vyf grondbehandelings getoets vir die vermoë om die Foc STR4-siekte te onderdruk en die plantgesondheid te verbeter wanneer toegedien as 'n voorkomende of genesende behandeling. ureum en Vermicompost toegedien as genesende behandeling en Effektiewe Mikrobes (EM) toegedien as genesende behandeling, het die voorkoms van siektes aansienlik verlaag in vergelyking met 'n onbehandelde kontrole. Die ureum behandeling het Foc STR4- spoortellings in grond aansienlik verminder, in vergelyking met 'n onbehandelde kontrole. Vermicompost het die plant lengte en die wortelmassa aansienlik verhoog. | af_ZA |
| dc.description.version | Masters | en_ZA |
| dc.embargo.terms | 2022-09-30 | |
| dc.identifier.uri | http://hdl.handle.net/10019.1/110488 | |
| dc.language.iso | en_ZA | en_ZA |
| dc.publisher | Stellenbosch : Stellenbosch University | en_ZA |
| dc.rights.holder | Stellenbosch University | en_ZA |
| dc.subject.lcsh | Bananas -- Breeding | en_ZA |
| dc.subject.lcsh | Soil fungi | en_ZA |
| dc.subject.lcsh | Fusarium wilt of banana -- Management | en_ZA |
| dc.subject.lcsh | Soil microbiology | en_ZA |
| dc.subject.lcsh | Cavendish bananas -- Diseases and pest resistance | en_ZA |
| dc.subject.lcsh | Bananas -- Effect of stress on | en_ZA |
| dc.subject.lcsh | Soilborne plant diseases -- Treatment | en_ZA |
| dc.subject.lcsh | Fusarium oxysporum -- Biological control | en_ZA |
| dc.subject.lcsh | Soils -- Quality -- Management | en_ZA |
| dc.subject.name | UCTD | en_ZA |
| dc.title | The manipulation of soil microbial composition for banana fusarium wilt management | en_ZA |
| dc.type | Thesis | en_ZA |