Managing Crop Biological Diversity on Farms

Managing the diversity of crop genetic resources on farms is of economic importance because it is a survival strategy for some of the world’s rural poor, though conserving them on farms also reduces the loss of potentially valuable alleles in genetic stocks still held locally. International agreements encourage the design of benefit-sharing schemes to support conservation through rewarding farmers—but mechanisms for doing so are still unclear. “Win-win” policy solutions occur when crop biodiversity is maintained on farms for the benefit of future generations while farmers themselves benefit today from a wider set of crop variety attributes for consumption or sale. Empirical approaches, guided by theoretical principles in economics and genetics, can be used to identify locations with high benefit-cost ratios for on-farm conservation. Policy instruments to support conservation in those locations include supply-related mechanisms such as community genebanks, biodiversity registers, and the introduction of modern varieties that complement the range of traits found in local varieties. When markets are not well developed and transaction costs are high, farmers’ supply of diverse crop varieties, and their derived demand for local landraces, can be enhanced by participatory plant breeding. As incomes rise and commercial markets develop, landraces will continue to be grown if there is consumer demand for a unique attribute that cannot be easily bred into or transferred to modern varieties. Yet, the necessary conditions for such market-based initiatives are not often met in the locations where landraces are cultivated. Protecting one landrace does not necessarily have desirable implications for either diversity conservation or social equity. The relative costs and benefits of such instruments have not yet been assessed rigorously.