Assessing the potential of medicinal plants- Where to start
M. Bannayan
Ferdowsi University of Mashhad, Faculty of Agriculture, P.O. Box 91775-1163,
Mashhad
Although there are over 350 000 plant species, fewer than 20 `major' crop species provide
for most human food needs. Within the rest of the plant kingdom there remain many
hundreds of underutilized food crops that have been grown locally for centuries and
which contribute to the food security of the world's poorest people. In poor and
impoverished regions of the world there are plants that have survived despite research
and despite science. This is our chance to find out what those plants would be like as
crops for the future — in climates of the future. With focussed scientific efforts applied to
unconventional crops we can do things that will make them more valuable, more useful
and more popular. Many of these crops are cultivated in hostile, tropical environments by
small-scale farmers without access to irrigation or fertilizers and with little guidance on
improved practices. Because the production and improvement of most underutilized
crops have been ignored or actively discouraged by agricultural scientists, breeders and
funding agencies, any attempts to improve their germplasm or management rely on local
knowledge and initiative. There are few examples of a multidisciplinary research effort
on an underutilized crop and no methodological framework that can be applied across a
range of underutilized species. Simulation models are robust tools to guide our
understanding of how a system responds to a given set of conditions. Crop simulation
models are increasingly being used in agriculture to estimate production potentials,
design plant ideotypes, transfer agrotechnologies, assist strategic and tactical decisions,
forecast real time yields and establish research priorities. Although there are growth
simulation models for a range of major crops, there have been few attempts to develop
models for underutilised species for which the factors controlling growth and
development are not well understood and the general literature is sparse. A major
objective for developing BAMnut was to provide a means of integrating our preliminary
understanding of the dynamics of crop growth as influenced by soil moisture and
environmental variables. This allows the agro-ecological potential and resource
requirements of the crop to be established. In particular, because BAMnut is a processbased model, it allows predictions of crop growth and yield to be generated and matched
with current and potential production environments beyond those used in the
development of the original model.