Genetic diversity analysis and nutritional assessment of cocoyam genotypes in Malawi
| dc.contributor.advisor | Labuschagne, Maryke T. | |
| dc.contributor.advisor | Herselman, Liezel | |
| dc.contributor.advisor | Benesi, Ibrahim R. M. | |
| dc.contributor.author | Mwenye, Obed John | |
| dc.date.accessioned | 2015-11-20T09:31:20Z | |
| dc.date.available | 2015-11-20T09:31:20Z | |
| dc.date.copyright | 2009-11 | |
| dc.date.issued | 2009-11 | |
| dc.date.submitted | 2009-11 | |
| dc.description.abstract | English: Cocoyam (C. esculenta (L.) Schott and X. sagittifolium (L.) Schott) belongs to the family Araceae. Cocoyam has the potential to contribute significantly to world agriculture in terms of food, nutrition and crop diversification. Despite this the crop remains neglected in terms of research focus. Limited or no information exists on the prevalence, preference and utilisation as well as the pattern and level of diversity that exists in cocoyam germplasm found in Malawi. This study determined the level and pattern of genetic diversity of cocoyam from Malawi using ethno-botany, morphological characters and AFLP markers. Mineral composition of selected genotypes was also determined. The ethno-botanical survey showed that farmers in Malawi maintain a large amount of cocoyam germplasm. These farmers have rich ethno-botanical and ecological knowledge of the cocoyam cultivars they conserve. Farmer’s preferences regarding cocoyam cultivars included uses of plant parts, adaptation and eating quality. Morphological characters showed high levels of variation among accessions. Two main species of cocoyam, Colocasia and Xanthosoma were identified based on leaf base shapes (petiole attachment). AFLP markers showed low levels of genetic diversity between accessions as opposed to the high morphological diversity. A combined (morphological characters and AFLP data) analysis using UPGMA clustering, PCA and AMOVA further alluded to the presence of the two cocoyam species within the germplasm. High levels of variation were detected between the two species and low levels of variation were observed within each of the two species (Colocasia and Xanthosoma). The PCA exhibited a better representation of the genetic diversity pattern than the hierarchical clustering. Accessions showed high levels of mineral composition. Potassium was identified as the major mineral component. Accessions also exhibited high levels of essential minerals (Ca, Fe and Zn). Incorporating cocoyam into the diet of the resource poor farmers could help in the fight of the most prevalent micro-nutrient deficiencies. A study on morphological and genetic diversity as well full nutritional assessment of the tubers and leaves of cocoyam from the whole country is recommended. In order to broaden the narrow genetic base observed importation of foreign material is recommended. | en_ZA |
| dc.description.abstract | Afrikaans: Amadumbie (C. esculenta (L.) Schott en X. sagittifolium (L.) Schott) behoort aan die Araceae familie. Amadumbie het die potensiaal om betekenisvol tot wêreldlandbou in terme van voedsel, voedingswaarde en gewasdiversifikasie by te dra. Ten spyte hiervan word die gewas nog steeds in terme van navorsing afgeskeep. Beperkte of geen inligting is oor die voorkoms, voorkeure en gebruik van die gewas sowel as die patroon en vlak van diversiteit wat voorkom in kiemplasma van Malawi beskikbaar. In hierdie studie is die patroon en vlak van genetiese diversiteit in amadumbie kiemplasma van Malawi met behulp van etnobotanie, morfologiese eienskappe en AFLP merkers bepaal. Minerale inhoud van geselekteerde genotipes is ook bepaal. Die etno-botaniese opname het getoon dat boere in Malawi ‘n groot hoeveelheid genotipes onderhou. Die boere wat die kiemplasma aanplant het ‘n ryk etno-botaniese en ekologiese kennis van die genotipes wat hulle bewaar. Die boere se voorkeur in terme van amadumbie cultivars sluit in die potensiële gebruik van plantdele, aanpassing en eetbaarheid. Morfologiese eienskappe het hoë vlakke van variasie tussen genotipes getoon. Die twee hoof spesies van amadumbie, Colocasia en Xanthosoma, is op grond van blaarbasis vorms (petiool aanhegting) geïdentifiseer. AFLP merkers het lae vlakke van diversiteit tussen genotipes getoon, wat teenstrydig was met die hoë morfologiese diversiteit. Gekombineerde analises (morfologiese eienskappe en AFLP data) met UPGMA groepering, PCA en AMOVA het die teenwoordigheid van twee amadumbie spesies in die kiemplasma bevestig. Hoë vlakke van variasie tussen die spesies en lae vlakke binne die twee spesies (Colocasia en Xanthosoma) is waargeneem. Die PCA het ‘n beter verteenwoordiging van die genetiese diversiteitspatrone as hierargale groepering gegee. Genotipes het hoë mineraalinhoudvlakke getoon. Kalium was die belangrikste minerale komponent. Genotipes het ook hoë vlakke van noodsaaklike minerale (Ca, Fe en Zn) gehad. Die insluiting van amadumbie in die dieet van hulpbron-arm boere kan tot die stryd teen mikro-element tekorte bydra. ‘n Volledige studie van morfologiese en genetiese diversiteit sowel as voedingswaarde analise van die knolle en blare van amadumbie van die hele land word aanbeveel. Die invoer van kiemplasma word aanbeveel, om die smal genetiese basis van die gewas te verbreed. | af |
| dc.identifier.uri | http://hdl.handle.net/11660/1686 | |
| 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 | Dissertation (M.Sc.Agric. (Plant Sciences (Plant Breeding))--University of the Free State, 2009 | en_ZA |
| dc.subject | Variation (Biology) | en_ZA |
| dc.subject | Taro -- Genetics | en_ZA |
| dc.subject | Taro -- Breeding -- Malawi | en_ZA |
| dc.subject | Food supply -- Malawi | en_ZA |
| dc.title | Genetic diversity analysis and nutritional assessment of cocoyam genotypes in Malawi | en_ZA |
| dc.type | Dissertation | en_ZA |