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Accueil du site → Doctorat → Royaume-Uni → 2000 → The genetic diversity of the sheanut tree (Vitellaria paradoxa) in the farming systems of northern Ghana

University of Southampton (2000)

The genetic diversity of the sheanut tree (Vitellaria paradoxa) in the farming systems of northern Ghana

Lovett, Peter Nicholas Conrad

Titre : The genetic diversity of the sheanut tree (Vitellaria paradoxa) in the farming systems of northern Ghana

Auteur : Lovett, Peter Nicholas Conrad.

Université de soutenance : University of Southampton

Grade : Doctor of Philosophy (PhD) 2000

Résumé
A broad literature review on ’The sheanut tree’ (Vitellaria paradoxa Gaertn.) revealed that this is a multi-purpose species highly valued for oil obtained from its seeds and traditionally maintained in the semi-arid agroforestry parklands of sub-Saharan Africa.In Ghana, results indicate that all phenotypic characters exhibited a wide range of continuous variation and a high degree of genetic diversity is suggested. Multivariate analysis implied the existence of possible ’varieties’ that were not geographically isolated. The latter finding was further supported by high estimates for geneflow from isozyme analysis, confirming previous suggestions that this is a widely outcrossing species. Clinical trends were identified which typically exhibited decreasing size and variation of morphological characters with increasing severity of environmental conditions. The exception to this general rule was the increase of seed width variation to the north east of the study area. It is suggested that this trait is related to integration in traditional agroforestry systems.This study also offers evidence that micropropagation techniques could offer a potential method for capturing genetic diversity of V. paradoxa. Axillary shoot proliferation was induced in apical shoots of seedlings when cultured in vitro with Murashige and Skoog nutrients reduced to half-strength in the presence of a combination of 6-benzyladenine and -napthaleneacetic acid. Adventitious roots were stimulated when cultured with Murashige and Skoog nutrients reduced to quarter-strength in the presence of indolebutyric acid. Further research on appropriate propagation techniques is recommended to allow ’methodical’ selection and continuation of a tree improvement process first started by African farmers thousands of years ago.

Présentation (ETHOS)

Page publiée le 7 février 2015, mise à jour le 15 novembre 2019