Jansen Van Rensburg W.S.,ARC Roodeplaat Vegetable and Ornamental Plant Institute |
Shanahan P.,University of KwaZulu - Natal |
Greyling M.M.,ARC Roodeplaat Vegetable and Ornamental Plant Institute
Acta Horticulturae | Year: 2013
Taro (Colocasia esculenta), known as amadumbe in South Africa, is traditionally cultivated in the coastal and subtropical areas of South Africa. The commercial potential of taro is being realised in South Africa with it being sold in some supermarkets. However, very little is known about the genetic diversity, introduction and movement of taro in South Africa. No registered cultivars exist in South Africa, only landraces, and no formal genetic improvement has been done. More information on the genetic diversity of taro is necessary before any genetic improvement can be attempted. Germplasm was collected in order to establish a representative collection. Germplasm was also imported from Nigeria. The germplasm collection (92 accessions) was characterised using simple sequence repeat (SSR) primers. Six primers sets resulted in a total of 52 scorable bands. The resulting profiles were scored as 1 for the presence of a band, or 0 indicating absence of a band. The data were analysed using PAUP, Phylip and ExcelStat to obtain a better understanding of the relationship between the different accessions. Cladograms were constructed using UPGMA cluster analysis. A high level of genetic diversity was observed within the South African germplasm, and three major clusters were identified in the cladogram. The accessions from the same locality did not always group together and some accessions collected from different provinces clustered together. Some of the local accessions clustered closer with the Nigerian accessions than with accessions from the same location. The results suggest that germplasm has and is being exchanged between farmers from different regions, and this is also supported by anecdotal information from farmers. The results indicated that further investigations on a molecular level are required to give a better understanding of the genetic diversity within the local taro germplasm and how it contrasts with foreign germplasm.
Kleynhans R.,ARC Roodeplaat Vegetable and Ornamental Plant Institute |
Myeza P.N.,ARC Roodeplaat Vegetable and Ornamental Plant Institute |
Laurie S.M.,ARC Roodeplaat Vegetable and Ornamental Plant Institute |
Visser A.,ARC Roodeplaat Vegetable and Ornamental Plant Institute |
And 2 more authors.
Acta Horticulturae | Year: 2013
The Agricultural Research Council - Roodeplaat Vegetable and Ornamental Plant Institute (ARC-Roodeplaat VOPI) is mandated to conduct research and technology development on commercial vegetables, indigenous and traditional vegetables, medicinal plants and indigenous flower bulb plants. The institute maintains more than 9000 accessions, including locally collected as well as imported germplasm. Material in the various genebanks is maintained either as seed in seed stores, in vivo in field and glass house genebanks or in vitro in tissue culture. Most of these collections are linked to active research programs at the institute with direct utilization in either breeding programs, plant pathology or cultivation research leading to the development of new cultivars and technologies. The genebank for example supports the only potato breeding program on the African continent. The development of cultivars adapted to the warmer and dryer climates can contribute to the availability of material that can address climate change and play a role in food security in rural areas. Besides the research outputs the genetic resources maintained at ARC-Roodeplaat VOPI play an important role in the sustainability of farmers. As the only source of disease-free and indexed material of potato, sweet potato and Lachenalia flower bulb cultivars in South Africa, the supply of material from the genebank ensures that farmers receive quality material to sustain good harvests, meet the demand for production as well as contribute towards food security. The potato genebank in this regard is the start of the potato certification scheme supporting the R 4.5 billion local potato industry and the sweet potato disease-tested scheme serves the R 34 million industry. Similarly, the traditional and indigenous vegetable genebank is the only seed source of certain species available in the country, leading to requests for seed from a variety of role-players. The plant genetic resources maintained in genebanks at ARC-Roodeplaat VOPI are utilized in various ways and very little of the research conducted would have been possible without these resources.
Visser D.,ARC Roodeplaat Vegetable and Ornamental Plant Institute |
Pett W.,Michigan State University |
Douches D.,Michigan State University
Acta Horticulturae | Year: 2013
Twenty one field trials using a genetically modified potato cultivar containing the Bacillus thuringiensis (Bt) gene were conducted between 2001 and 2007, in six provinces throughout South Africa. The target pest was the potato tuber moth, Phthorimaea operculella (PTM). Six field trial permits, as well as a permit for the conducting of contained use experiments in laboratories and a greenhouse, were issued by the Registrar of Genetically Modified Organisms Act of South Africa. Movement of all seed tubers, planting, harvesting and storing was strictly monitored by inspectors of the Department of Agriculture. Regular inspections during the growing season of all field trials were also carried out. Inspectors were found to be helpful and professional, although misunderstanding regarding planting dates and locations sometimes occurred. In some instances, the strict requirements, as stipulated in the permit, were altered, after written objections to the Registrar. Seed tubers for all field trials had to be produced in a specially adapted greenhouse, modified to multiply mini tubers in a vermiculite substrate open hydroponic system. Most farmers that participated in our trials were helpful and committed to our trials. Activists critically commented on all aspects of our trials, but all their concerns could usually be addressed. A few setbacks were experienced but it did not influence the overall objectives of the project. At all locations where PTM occurred, the Bt-potato provided excellent control of PTM, compared to the non-transformed potato. Six years of field trials with Bt-potatoes were conducted successfully in South Africa. However, strict regulations, instructions and inspections always impacted on the normal potato field trial processes.
Kleynhans R.,ARC Roodeplaat Vegetable and Ornamental Plant Institute
Acta Horticulturae | Year: 2011
Genera from the Hyacinthaceae family have been utilized in breeding programs at the Agricultural Research Council for many years with the aim to develop new products for the international floriculture market. Through conventional breeding, several Lachenalia and Ornithogalum cultivars were released. The Lachenalia breeding program was the only active breeding program during the past 5 years and several potential new lines (comprising of different colour combinations and flower forms) are available for commercial evaluation. Besides conventional breeding, a project on the use of mutation technology has also resulted in the availability of new lines. Members of the Hyacinthaceae are particularly suitable for mutation breeding because two of the positive circumstances for mutation breeding can be combined: vegetative propagation and single cell origin of adventitious buds on leaf tissue. A method combining irradiation and tissue culture was developed to induce mutations in four genera, namely Lachenalia, Ornithogalum, Eucomis and Veltheimia. To date at least four potential new varieties have been identified from three of the four genera. These lines have been initiated in tissue culture for multiplication purposes. When large quantities of material are available, application for Plant Breeders Rights and commercial establishment will take place.