A view on animal and plant genetic resources in the light of climate change
Irene Hoffmann, Food and Agriculture Organization of the United Nations
Genetic resources for food and agriculture are critical for food security and rural development. They allow farmers to select crop varieties and develop new breeds in response to changing conditions, including climate change, new or resurgent disease threats, new knowledge of human nutritional requirements, and changing market conditions or changing societal needs – all of which are largely unpredictable. What is predictable is increased future human demand for food. The effects will be most acute in developing countries, where the increase in demand is expected to be greatest, and occur at a rate faster than increases in production, and where climate change is projected to have its greatest impact.
Crop, and particularly livestock, production both contribute to and are affected by climate change. In addition to the physiological effects of higher temperatures on individuals, the consequences of climate change are likely to include increased risk that geographically restricted rare populations will be badly affected by disturbances. Crop wild relatives are by far the most vulnerable group as they can neither benefit from agricultural practices which somehow can buffer the effects of climate change, nor are they adequately conserved in ex situ facilities. Indirect effects may be felt via ecosystem changes that alter the distribution of diseases or affect the supply of feed. Breeding goals may have to be adjusted to account for higher temperatures, reduced inputs and greater disease challenge. Species or breeds and varieties that are well adapted to such conditions may become more widely used. Climate change mitigation strategies, in combination with ever increasing demand for food, may also have an impact on species and breed/variety utilization. This may lead to the neglect of the adaptation potential of local breeds in developing countries.
Adaptation is necessary to respond adequately to climate change, food security and livelihoods needs, and natural resources conservation. However, genetic diversity today is rapidly declining globally as specialization in plant and animal breeding and the standardizing effects of globalization advance. Many breeds/varieties are already well adapted to high temperatures and harsh environments, but the wider diffusion of such germplasm or their incorporation into breeding programmes is restricted by the limited extent to which they have been characterized and improved in structured breeding programmes and trade and sanitary constraints. However, adaptation traits are more difficult to study and to record than production traits, have lower heritability, higher levels of non-additive genetic variation and phenotypic variance, and are more susceptible to genotype-by-environment interaction.Given the potential for significant future changes in production conditions and in the objectives of agricultural production, it is essential that the option value provided by crop and animal genetic diversity be secured. This requires better characterization of germplasm, production environments and associated knowledge; the compilation of more complete genetic resources inventories; improved mechanisms to monitor and respond to threats to genetic diversity; more effective in situ and ex situ conservation measures; genetic improvement programmes; increased support for developing countries in their management of genetic resources; and wider access to genetic resources and associated knowledge.