Crop Genetic Diversity, Productivity and Stability of Agroecosystems. A Theoretical and Empirical Investigation
| Author | Charles Perrings,Salvatore Di Falco |
| Published date | 01 May 2003 |
| DOI | http://doi.org/10.1111/1467-9485.5002006 |
| Date | 01 May 2003 |
CROP GENETIC DIVERSITY,
PRODUCTIVITY AND STABILITY OF
AGROECOSYSTEMS. A THEORETICAL
AND EMPIRICAL INVESTIGATION
Salvatore Di Falco
n
, and Charles Perrings
nn
Abstract
This paper purports a model of farmers’ crop choices in an uncertain environment.
The model shows that profit maximizing farmers will choose a crop mix
characterised by greater crop diversity if diversity is positively related to
productivity and negatively correlated with production and income variability.
An application using data from a Vavilov megadiversity spot, southern Italy, from
1970 up to 1993 is provided to test model hypotheses. It is found that interspecies
crop genetic diversity is positively related to mean income and negatively related to
the variance of income.
I Introduct ion
Both the Biodiversity Convention and the International Treaty on Crop Genetic
Resources encourage signatory countries to promote on-farm conservation of
agrobiodiversity. Crop Genetic Conservation generally involves one of two
strategies: ex situ germ plasm preservation in gene and seed banks, and in situ
conservation of crops and wild relatives. Ex situ conservation ensures against the
loss of genetic material from rapidly changing systems. On the other hand, in situ
conservation protects both dynamic, evolutionary genetic processes and the
complexity of genetic interactions in the agricultural ecosystem, both of which
are lost in ex situ conservation (Brush, 1995). Crop genetic diversity is important
at both global and local levels. At the global level, plant genetic resources are
valued for their role in the genetic ‘improvement’ of cultivated species to meet
the challenges posed by changing levels of demand, due to population growth,
and changing supply conditions, due to climate change and attendant changes in
pest and pathogen risks. At the local level, Interspecies Crop Genetic Diversity
(ICGD, hereafter) plays an important role in supporting the productivity and
stability of agroecosystems.
The evidence on the relationship between interspecies crop genetic diversity
and mean farm incomes is mixed. There is some limited evidence that diverse
n
University of York (UK)
nn
University of York (UK)
Scottish Journal of Political Economy, Vol. 50, No. 2, May 2003
rScottish Economic Society 2003, Published by Blackwell Publishing, 9600 Garsington Road, Oxford OX4 2DQ, UK
and 350 Main Street, Malden, MA 02148, USA
207
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