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The management of South Africa's heritage resources is still lacking a great deal and many resources are being destroyed by ignorance, development and plain greed. Although South African legislation is adequate in theory, commitment on the side of the government in terms of staff, skills and resources to implement it, is not forthcoming. On the global platform however, we have much to learn as heritage management is regarded as a priority in most of the first world countries. Four steps to reach this goal, is summarizing it effectively: the identification, understanding how it was created and used, selecting the appropriate conservation techniques, and stakeholder involvement. The focus of this study is on the diverse heritage resources of the Blyde Canyon Nature Reserve in Mpumalanga, the largest green canyon in the world. This area has a rich, irreplaceable and unexplored cultural heritage. The tangible and intangible values were classified in a typological framework, including archaeology (stone age and iron age), rock art, historical industrial features, sacred sites, monuments, burial sites, graves and historic tourist features. Authorities are in the process of changing the status of the Nature Reserve to that of a National Park and it is also envisioned to nominate this unique natural and cultural landscape for World Heritage status. The database and overall objectives of this study has been identified to highlight the relevance and importance of the cultural heritage resources and to ensure its future protection and management. This area is already a popular tourist destination which is currently under-utilised, and by contributing to the protection and responsible development of the heritage resources, and by having the correct management principles set in place, the visitor experience will not only be enhanced but the surrounding towns and communities will benefit extensively. Copyright / Dissertation (MHCS)--University of Pretoria, 2010. / Historical and Heritage Studies / unrestricted

L’hybridation avec des ressources génétiques allochtones est largement pratiquée chez les plantes ornementales pour introduire de nouveaux caractères. Au cours du 19e siècle, âge d’or de la sélection des rosiers en France, des rosiers asiatiques ont été introduits en Europe. L’objectif ici est d’étudier l’évolution de la diversité génétique des rosiers cultivés en France au cours de cette période. La diversité a été étudiée à l’échelle du génome puis à l’échelle de gènes candidats codant pour des caractères potentiellement sélectionnés au cours du 19e siècle. Un échantillon de 1228 rosiers illustrant la diversité génétique des rosiers français cultivés à cette période a été génotypé avec 32 microsatellites. Une large diversité, structurée en seize groupes génétiques et une différenciation entre les rosiers anciens européens et les rosiers asiatiques ont été détectées. Un déplacement du fond génétique des hybrides cultivés d’un type européen vers un type asiatique a été observé au cours du 19e siècle. Les croisements fréquents et/ou la sélection pour des caractères présents chez les rosiers asiatiques ont pu induire cette évolution. Certains caractères phénotypiques, comme la remontée de floraison, deviennent prépondérants. Onze gènes candidats ont été séquencés et leur diversité a été analysée sur un sous-échantillon de 365 rosiers. Parallèlement au fond génétique, certains gènes présentent un rapprochement génétique vers des allèles asiatiques. Pour le gène KSN, une augmentation de la fréquence d’allèles portant le rétrotransposon copia, responsable de la remontée de floraison, est observée. / Innovation in ornamental plant breeding is commonly obtained by hybridization with newly introduced genetic resources. During the 19th century, golden age for rose breeding in France, Asian roses were introduced in Europe. Our objective here was to study and explain the evolution of rose genetic diversity in France during this period of time. The diversity was studied at the genome scale and at the candidate gene scale. A large sample of 1228 garden roses illustrating the French rose diversity from this period of time was genotyped with 32 microsatellites markers. A wide diversity, structured into sixteen genetic groups, was observed. A geneticdifferentiation was detected between ancient European and Asian accessions and a continuous temporal shift was observed in cultivated hybrids from a European to an Asian genetic background during the 19th century.Frequent crosses with Asian roses along the 19th century and/or selection for Asiatic traits may have induced this shift. Some phenotypic traits, like continuous flowering, became overriding traits. Eleven candidate genes, which were potentially selected during the 19th century, were sequenced and their diversity was analyzed on a subsample of 365 roses. Simultaneously to the genetic background, some genes are gettingcloser to Asian alleles. For the KSN gene, an increase in the frequency of alleles carrying the retrotransposon copia, responsible for continuous flowering, is observed.