The International Consortium on Agricultural Biotechnology Research (ICABR)
Assessing the potential of
underutilised crops: can the Gene
Revolution succeed where the
Green Revolution Failed?
S.N. Azam-Ali and F.J. Massawe
Tropical Crops Research Unit, University of Nottingham
School of Biosciences, Sutton Bonington Campus, Loughborough LE12 5RD
The main beneficiaries of breeding, genetic manipulation, agronomic research and extension activities on crop plants have been commercial farmers and agricultural industries in developed countries. This is most apparent where developments in molecular and information technologies have been applied to agriculture. Such technologies have never been integrated within a collective effort to improve the yield, value or status of underutilised crops. This paper considers how molecular and information technologies can be usefully linked with more conventional approaches to assess the potential of underutilised crops. A review is provided of how significant increases in the yields of major crops, principally wheat, rice and maize, were achieved through the so called Green Revolution. yield The consequences of this strategy on the diversity of agricultural species and systems are presented, with particular emphasis on subsistence agriculture in sub-Saharan Africa. The trend for modern varieties and monocultures to displace traditional landraces and multiple cropping systems is discussed and their relative advantages and disadvantages are considered for contrasting environments.
An alternative strategy is presented based on our experience with bambara groundnut (Vigna subterranea L. Verdc) at collaborating institutions in Africa and Europe. Our experience demonstrates how local knowledge, genetic technologies, research in fields, glasshouses and laboratories, crop simulation modelling and information technology might be linked within a methodological framework to rapidly assess the potential of any underutilised crop. Our combined experience may help to establish a methodology by which growers, researchers and international agencies can integrate their knowledge and understanding of any particular underutilised crop and apply similar principles to accelerate the acquisition of knowledge on other underutilised species. The use of a methodological framework provides a basis for activities that maximise knowledge, minimise duplication of effort, identify priority areas for further research and dissemination and derive general principles for application across some or all underutilised crops. It also allows policy makers and planners to make comparative decisions on the nutritional, economic and research importance of different underutilised and major species. In particular, the incorporation of a generic crop simulation model within the methodological framework may assist growers, extension agencies and scientists to refine general recommendations for any particular crop to local conditions.
Crop Production and the Legacy of the Green Revolution
In the second half of the last century Agriculture was transformed by what became known as the Green Revolution. This technological package combined potentially high yielding varieties of wheat, rice and, to a lesser extent, maize, with inputs such as fertilizers, pest and disease control and irrigation. The advantages of potentially higher yielding varieties meant that Green Revolution Technology was rapidly adopted by most farmers in the developed world. It was also embraced by those farmers in the developing world who had access to cash or credit facilities that allowed them to purchase the required technology. Despite its successes, the Green Revolution was not uniformly applicable throughout the world and it has had little impact in regions such as sub-Saharan Africa. A further consequence of the Green Revolution is other trend that has accompanied the increase in total food production the concentration of research, breeding and extension effort into a few species with a consequent reduction in the number of species cultivated and the diversity of cropping systems. During the period of the Green Revolution, mmIn this way, any traditional food crops have been replaced by a small number of staple crops capable of achieving higher yields in response to fertilizers and irrigation across a wider range of environments. This has resulted in the further advance of major crops, such as wheat, rice and maize cultivated as monocultures, into areas previously occupied by a diverse range of local crops and cropping systems.
Are there any Alternatives to the Green Revolution?
It could be argued that the subsistence agricultural sector should not attempt to adopt the Green Revolution model but should seek an alternative strategy. However, before rejecting the existing approach, we need to ask `which potential strategies and species could stabilise or increase crop production in subsistence environments? One possibility is to identify the potential of those underutilised indigenous species and management systems that are best suited to the natural constraints imposed by local climates and soils.
Can we use modern technologies to improve underutilised species?
The use of computer models and molecular technologies are familiar in many high value production systems based on the major crop species. Agronomic research can benefit considerably from both these developments and commercial sponsors have often been generous in their support of such activities. However, do these high level technologies have a role to play in improving subsistence agriculture? More specifically, can they help to make substantial gains in our knowledge of these crops and overcome some of the constraints that presently limit their genetic improvement and productivity in low input farming systems beyond that achievable by conventional means?
Linking Information and Molecular Technologies to Evaluate Underutilised Crops
Research on bambara groundnut (Vigna subterranea L. Verdc) is a rare example of a multidisciplinary, international effort to study and assess the potential of any underutilised crop. Since 1988, scientists in four European countries, United Kingdom, the Netherlands, Germany and Italy, have joined forces with scientists, growers, traders and consumers in Botswana, Tanzania, Sierra Leone, Swaziland, Namibia and Zimbabwe to work on this indigenous African legume. Together, their efforts provide a comprehensive assessment of the ecophysiology, agronomy, nutritional biochemistry, agroprocessing, genetics, and marketing potential of bambara groundnut. Thoughst all of these activities were not always collaborative or systematically structured, the experience provides a basis to consider whether a similar approach can be used for rapid evaluation of other under-researched species. Further details of the approach presented below appear in Azam-Ali and Squire (2001) and Azam-Ali et al. (2002).
In this paper we have drawn on our experience of working on one underutilised crop - bambara groundnut. It is unlikely that similar information exists on any other underutilised crop. However, our activities have yet to be fully evaluated nor the recommendations deriving from them disseminated to the growers themselves. More importantly, we have yet to apply any of the principles established on bambara groundnut to any other crop or to demonstrate that recent developments in genetic and information technologies can usefully serve subsistence agriculture. Despite this, we believe that the strategy described above can achieve real, rapid progress on underutilised crops. It is clear that the greatest progress for subsistence agriculture in hostile environments will be made through a multidisciplinary and multinational approach. In this strategy, molecular (`gene revolution) technologies are part of a spectrum of activities that are more appropriate to these objectives than to continue to rely on the conventional (`green revolution) model. As with major species, no one discipline is likely to have all the answers for underutilised species.
Azam-Ali, S.N. and Squire, G.R. (2001). Principles of Tropical Agronomy. CAB International, Wallingford, UK. (In press).
Azam-Ali, S.N., Sesay, A., Karikari, S., Massawe, F.J., Aguilar-Manjarrez, J., Bannayan, M. and Hampson, K.J. (2002) Assessing the potential of an underutilised crop - A case study using bambara groundnut. Experimental Agriculture (submitted).