Host-plant interactions and resistance mechanisms to banana weevil Cosmopolites sordidus (Germar) in Ugandan Musa germplasm
| dc.contributor.advisor | Labuschagne, M. T. | |
| dc.contributor.advisor | Louw, Schalk | |
| dc.contributor.author | Kiggundu, Andrew | |
| dc.date.accessioned | 2017-04-26T07:47:30Z | |
| dc.date.available | 2017-04-26T07:47:30Z | |
| dc.date.issued | 2000-03 | |
| dc.description.abstract | English: Banana is an important subsistence crop in many tropical regions of the world. In the East African Great Lakes region it constitutes a staple food for more than 17 million people. Among many production constraints, banana weevil (Cosmopolites so rdidusi. is the most serious pest to the crop. The tunnels caused by the boring larvae interfere with water and mineral uptake, and provide entry for fungi and bacteria. Most importantly this weakens the corm, leading to toppling of plants even in slight winds. Host plant resistance is considered the basis of any successful integrated pest management plan, if the banana weevil problem is to be solved by the resource poor farmers. The screening trial of 45 Ugandan Musa germplasm accessions revealed that the plantain subgroup (AAB) was most susceptible to banana weevil followed by East African highland banana clones. The exotic bananas, especially Kayinja, Bluggoe (ABB), Kisubi and Ndiizi (AB) were resistant to banana weevil. Plantain derived tetraploid hybrids of the wild banana Calcutta-4 were also susceptible, indicating dosage effect of the susceptible gene. Mbwazirume, Tereza and Nakyetengu have been found to be relatively resistant local land races and they are recommended as possible resistant selections. Total inner damage was found to be the best criteria for screening, and selecting for weevil resistance, since it scored the highest heritability and was highly correlated with all other weevil damage indices. Significant phenotypic and genotypic correlations were found between corm hardness, dry matter content, sap/resin production, suckering ability and corm size and banana weevil damage. These were therefore considered important mechanisms of resistance in Musa and this indicated that banana weevil resistance is a complex polygenic trait. In agreement with the literature studied. antixenosis was not found to be important as a resistance mechanism in Musa. However. results from various no-choice experiments on hatchabil ity and development revealed significant differences. The previously observed resistance cultivars Kayinja. Yangambi-km5 and FHIA03, unlike the more susceptible plantains and EAHBs, significantly increased developmental time and in some cases caused mortality of immature weevil stages. Preliminary studies on the influence of secondary metabolites were undertaken. The results showed the presence of two or three compounds indicated by peaks on HPLC chromatograms of methanol extracts of corms from resistant cultivars (e.g. Kayinja and FHIA03) that were not present in susceptible cultivars (e.g. Atwalira and Gonja). These substances were also not present in some resistant cultivars like Yangambi-km5 and Cavendish, both of the AAA genome group. This was yet another indication that resistance is complex and these different factors are important in different groups of cultivars. | en_ZA |
| dc.description.abstract | Afrikaans: Piesangs (Musa) is "n belangrike onderhoudgewas in heelwat tropiese streke van die wêreld. In die Oos-Afrika Groot Mere area is dit die stapel voedsel van meer as 17 miljoen mense. Piesang snuitkewers (Cosmopolites sordidus) die ernstigste plaag op piesangs, is een van 'n aantal produksie beperkings wat bestaan. Die tonnels wat daartoe lei word deur borende larwes benadeel water en mineraalopname en gee ingang aan fungi en bakterië. Die grootste probleem is dat die ondergrondse stam van die plant verswak word, wat veroorsaak dat die plant omval, selfs as 'u ligte wind waai. Gasheer plant weerstand word gesien as die basis van enige geïntegreerde plaagbestuursplan indien die piesang snuitkewer probleem opgelos moet word deur hulpbron arm boere. Die evaluasie proef van 45 Ugandese Musa kiemplasma lyne het aangetoon dat die kook piesang subgroep (AAB), die mees vatbaar was, gevolg deur Oos Afrika hoogland piesang klone. Eksotiese piesangs, veral Kayinja. Bluggoe (AAB), Kisubi en Ndiizi (AB) was weerstandbiedend teen piesang snuitkewer. Kook piesang afgeleide tetraploïede basters van die wilde piesang, Calcutta-4, was ook vatbaar, wat aangetoon het dat daar 'n dosis effek is van die vatbare geen. Mbazirume, Tereza en Nakyetengu is aangetoon as redelike weerstandbiedende plaaslike landrasse en is aanbeveel as moontlike bronne van weerstand. Totale binne-skade is aangetoon as die beste kriterium vir evaluasie en seleksie van snuitkewerweerstand. omdat dit die hoogste oorerflikheid getoon het en die hoogste gekorreleer was met ander snuitkewer skade metings. Betekenisvolle fenotipiese en genotipiese korrelasies is vir ondergrondse stam hardheid, droë materiaal opbrengs, sap/gom produksie, suier produksie vermoë en ondergrondse stam grootte en piesang snuitkewer skade gevind. Dit was dus die eienskappe wat as aanduiers van belangrike meganismes van weerstand in Musa gesien is. Piesang snuitkewer weerstand is aangetoon as 'n komplekse poligeniese eienskap. Antixenose is rue aangedui as 'n weerstandsmeganisme in Musa me. Dit was in ooreenstemming met werk van ander navorsers. Resultate van' n aantal nie-keuse proewe vir eier uitbroeiing en ontwikkeling het betekenisvolle verskille aangetoon. In vorig geïdentifiseerde weerstandbiedende cultivars, naamlik Kayinja, Yangambi-km5, en FHIA03, het snuitkewers "n betekenisvolle langer ontwikkelingstyd getoon, en in sommige gevalle wa daar mortaliteit van onvolwasse snuitkewer fases. Dit was in teenstelling met meer vatbare kook piesangs en Oos Afrika hoogland piesangs. Voorlopige studies oor die invloed van sekondêre metaboliete is onderneem. Die resultate het die teenwoordigheid van twee of drie stowwe aangetoon by wyse van pieke op die HPLC chromatogram van metanol ekstrakte van ondergrondse stamme van weerstandbiedende cultivars (bv. Kayinja en FHIA03), wat nie teenwoordig was in vatbare cultivars nie (bv. Atwalira en Gonja). Hierdie stowwe was ook nie teenwoordig in sekere weerstandbiedende cultivars soos Yangambi-km5 en Cavendish, beide AAA genoom groep. Dit was nog 'n aanduiding dat weerstand' n komplekse eienskap is en dat verskillende faktore belangrik is in verskillende groepe cultivars. | af |
| dc.identifier.uri | http://hdl.handle.net/11660/6163 | |
| dc.language.iso | en | en_ZA |
| dc.publisher | University of the Free State | en_ZA |
| dc.rights.holder | University of the Free State | en_ZA |
| dc.subject | Bananas -- Disease and pest resistance | en_ZA |
| dc.subject | Bananas -- Breeding | en_ZA |
| dc.subject | Beetles -- Host plants | en_ZA |
| dc.subject | Dissertation (M.Sc.Agric. (Plant Breeding))--University of the Free State, 2000 | en_ZA |
| dc.title | Host-plant interactions and resistance mechanisms to banana weevil Cosmopolites sordidus (Germar) in Ugandan Musa germplasm | en_ZA |
| dc.type | Dissertation | en_ZA |