Crop diversity is the raw material for the development of new and improved varieties, which provide a range of important benefits to farmers and consumers.
Researchers have been assembling and managing ex situ collections of crop diversity in a systematic manner for over a century, securing traditional crop varieties and related wild species from remote, dispersed locations into genebanks. Such genebank collections provide safe, economical means to secure plant genetic resources for food and agriculture (PGRFA) and ensure that scientists have ready, convenient access to diversity they need to improve crops.
Without access to the diversity already stored in genebanks, researchers and scientists embarking on a crop improvement program would have little alternative but to create their own collections from scratch. This process would be expensive and time-consuming for an individual breeder. To illustrate, it would cost USD 6 million, or USD 120 per accession, not including the costs of building the facility or of ongoing conservation thereafter, to fully incorporate 50,000 samples of cultivated rice into a genebank collection (Hawtin et al. 2011).
In this brief, we describe a range of economic benefits that crop diversity offers with the aim to increase our understanding and awareness of the importance of conserving PGRFA. Economic valuation is one way to define and measure values that are useful to consider in making policy decisions that involve allocation of resources from a society wide perspective. In the case of crop diversity, the values can be difficult to estimate because they are usually realized only when a useful trait is identified and incorporated into crop varieties. This difficulty poses a challenge in justifying the costs of conserving crop diversity.
We focus here on the “use values”, which refer to the benefits derived from the usefulness of crop diversity in achieving a goal, e.g., improving crop productivity, improving yield stability and disease/pest resistance, enhancing nutritional content of crops, minimizing adverse environmental impacts, and rebuilding agricultural systems. Such benefits will be difficult to realize without the crop diversity already conserved in genebanks.
1. Improving crop productivity
A large body of research has documented the high rates of return from the use of PGRFA by showing how various crop varieties led to the improvement of agricultural productivity through breeding and the release of new and improved varieties. In particular, a significant share of the impact of CGIAR research and breeding can plausibly be attributed to the international genebanks [Box 1].
2. Improving yield stability and disease/pest resistance
Crop diversity has contributed not only to the level of crop yields, but also to their stability [Box 2]. Yield stability is especially critical for farmers in vulnerable, marginal situations. Gollin (2006) finds declining variability of maize and wheat yields in developing countries that is strongly associated with the spread of improved varieties. Other studies put values on long-standing efforts in breeding for disease and pest resistance. More importantly, agricultural systems globally have largely avoided major crop failures, in part because more frequent turnover of varieties has brought new sources of resistance (Renkow and Byerlee 2010).
3. Enhancing nutritional content of crops
More than two billion people in the world do not get enough essential vitamins and minerals – such as vitamin A, zinc, and iron – because more nutritious foods are too expensive or simply unavailable (HarvestPlus 2014). Through biofortification, HarvestPlus and its partners have developed new varieties of staple food crops that contain higher amounts of key nutrients [Box 3]. While impact studies have not considered aggregate adoption and long run use, this type of work is likely to accelerate with the scaling up of biofortification research by CGIAR and partners (Renkow and Byerlee 2010).
4. Minimizing adverse environmental impacts
Crop genetic improvement has also resulted in increases in resource-use efficiency in farms, minimizing adverse pressures on the environment. While the early varieties of the Green Revolution were input intensive, there has been a shift towards improved varieties that require less pesticide, fertilizer, water, labor, and indeed, land [Box 4].
5. Rebuilding agricultural systems
Beyond the research programs on crop improvement, the CGIAR has also been instrumental in helping to rebuild agricultural systems in at least 47 developing countries affected by conflicts and natural disasters across Asia, Africa and Latin America, including through the restoration of crop diversity (Varma and Winslow 2005) [Box 5]. The economic (and cultural) values of such contributions have not been estimated, but are clear additional benefits beyond the contribution of crop diversity to improvement programs.
[Box 1] Improving crop productivity
[Box 2] IMPROVING YIELD STABILITY AND DISEASE AND PEST RESISTANCE
[Box 3] ENHANCING NUTRITIONAL CONTENT OF CROPS
[Box 4] MINIMIZING ADVERSE ENVIRONMENTAL IMPACTS
[Box 5] REBUILDING AGRICULTURAL SYSTEMS
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 The Consultative Group on International Agricultural Research (CGIAR) is a strategic alliance of countries, international and regional organizations, and private foundations supporting 15 international agricultural research centers.