Conclusions

Several areas for the empirical measurement of farmer-based conservation of CGR were presented. These practical diagnostic tools can be used to target an in situ conservation program, as well as to understand the key constraints that a program would face over a longer planning horizon. Simple, analytic survey questions can be combined to yield a description of basic parameters of overall seed management. The history of seed showed that local landrace populations were characterized by a bimodal age distribution, divided between long periods of saving seed by the same farmer and recent renewal of seed. The documentation of seed sources shows the majority within the same family or the same village, with a small flow from outside the village. However, from a dynamic perspective, small amounts of seed renewal and inflow could accumulate to shape the evolution of local populations. This intertemporal accumulation of genetic flows would have different rates depending on the scale of analysis, whether it was for an individual farmer, a village, or a region. Furthermore, any conservation equilibrium appears unstable, as over time farmers are reducing system diversity and reducing area planted (and, therefore, effective population sizes). Finally, factors that seem unrelated to crop populations, such as labor markets, cash crop markets, transportation, or transactions costs, can have effects on the management of CGR and the stability of local populations.

The dynamic nature of crop populations creates difficulties for acquiring data over a long time horizon. In the empirical case presented here estimates were provided from current trends and from questions about recent history. The dimension of the crop population is important to conservation, and therefore the sample frame must be calibrated to take into account village and regional effects on populations. The intertemporal and interregional dimensions of seed systems combine to make the crop populations moving targets that may not have definite boundaries. The goal of the conservation program may be to focus on these aspects of the seed system related to flows of genetic material and continual selection by farmers under local conditions.

Finally, the issues of the long-term sustainability of in situ conservation remain unresolved because of contrary processes in market integration, agricultural specialization, and transactions costs for farm labor. In many areas of diversity of CGR, traditional varieties remain predominant or popular, but relying on this de facto conservation may require documentation of the forces affecting the decline in genetic diversity. The reduction of diversity may proceed on various fronts at the same, and it will be difficult to separate the simplification of agricultural production systems from the transfer of resources within the family to other income activities, such as cash crops or migration. However, a focus on the components of the evolutionary process, such as seed selection and exchange, may allow a conservation program to remain flexible in the face of such economic pressures.

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