The future of plant virology in Africa
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Thresh, Michael. 1998. The future of plant virology in Africa. Spore 76. CTA, Wageningen, The Netherlands.
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Dr Michael Thresh is Honorary Professor of Plant Virus Ecology at the Natural Resources Institute, University of Greenwich, UK. He first worked in Ghana (1953-1960) and then returned to the UK. From 1970 onward, he undertook numerous assignments in...
Dr Michael Thresh is Honorary Professor of Plant Virus Ecology at the Natural Resources Institute, University of Greenwich, UK. He first worked in Ghana (1953-1960) and then returned to the UK. From 1970 onward, he undertook numerous assignments in Africa and elsewhere on behalf of the UK Overseas Development Administration. African crops are affected by many viral diseases, some of which cause serious losses and undermine food security. Given this it is reasonable to ask: Are there sufficient virologists in Africa? Are the facilities and resources available to them adequate? Does African plant virology receive sufficient support from the wider scientific community? The answer to these questions is a resounding 'no'; so what can be done to improve the situation? The number of plant virologists in Africa is low in relation to the wide range of crops grown there, the huge areas of land under cultivation and the magnitude of other problems encountered. Plant virology in Africa has not always been in such a parlous state. In the early decades of this century, when the discipline was still at an early stage of development, the virology being done in various parts of Africa was comparable to that being done in Europe and North America. Maize streak, groundnut rosette, tobacco and cotton leaf curl and several other important virus diseases were described during this period and considerable progress was made in transmission studies and in developing resistant varieties. The disparity began to emerge after the Second World War when the electron microscope, ultracentrifuge and serological techniques became generally available in developed countries. This, and the big expansion in agricultural research, led to rapid progress in purification, characterisation and identification of viruses and facilitated the development of control measures. Progress has continued, although there has been a trend towards a more fundamental approach associated with the spectacular developments in nucleic acid chemistry and molecular biology. In recent decades, some progress has been made in Africa but the overall effort has been limited and has lacked resources and continuity. Institutes in Europe and North America have made substantial contributions in the study of African viruses and providing of training and consultants. The UK-funded virology project in Kenya, and the French ORSTOM project in Côte d'Ivoire, have been particularly influential and successful in exploiting such linkages. Both began in the 1970s by identifying the main viruses present in the two countries and went on to conduct detailed studies of cassava mosaic disease. Important work has also been done at the Virology Unit of the International Institute of Tropical Agriculture, Ibadan, Nigeria. Further progress is possible. One possibility is through increased contact with South Africa, where there are well-equipped laboratories and there is a long history of research in virology. Much could be achieved using modern methods of virus detection that use extracts or dried specimens, thus presenting no quarantine risk. However, the problems do not end with detection and identification. There is a need to use the results obtained in epidemiological studies and to develop resistant varieties or other control measures. Such studies present difficulties because of seasonal variation and other vagaries of field experimentation. Moreover, there is a need for specialist expertise and for support from plant breeders and those concerned with transmission vectors. This provides scope for a multi-disciplinary approach as in the 1970s UK-funded project in Ghana on breeding for resistance to cocoa swollen shoot disease. More recently there have been epidemiological studies mounted by staff of the UK's Natural Resources Institute on cassava mosaic, maize streak and other diseases. Different approaches have been adopted by donors and international agencies in supporting plant virology in Africa, and there is a sound foundation on which to build. However, there is a need for policy-makers, administrators and donors to appreciate the particular needs of plant virology. These are arguably greater than those of other crop science disciplines because of the relatively low number of trained and available personnel, and the need for sophisticated equipment and facilities. It is also necessary to recognise the need to establish facilities and training courses in Africa, rather than to maintain the current heavy dependence on resources in developed countries. Indeed, it is becoming increasingly difficult to arrange suitable training courses overseas as the research programmes and priorities in developed countries differ so greatly from those in Africa, where there is a continuing need for 'biological' studies of the type done elsewhere after World War II. More opportunities for the exchange of knowledge are essential. For example, there is a need for a conference to follow up the CTA seminar on cassava mosaic disease which was held in Côte d'Ivoire in 1987. Above all, there is a need to bring together plant virologists from developed and developing countries, together with representatives of donors and funding agencies, for discussions on the future of plant virology in Africa and in order to develop an action plan to address present weaknesses. Dr Michael Thresh, Natural Resources Institute, University of Greenwich, Central Avenue, Chatham Maritime Kent ME4 4TB UK Fax: + 44 1634 883379 Email: c/o%20B.Waite@greenwich.ac.uk http://www.agricta.org/Spore/spore76
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