Wild Plants and the Future of Crops

Fig.1. Members of CIAT’s Genetic Resources Program in the minus 20℃
gene bank (Credit: Neil Palmer/CIAT, 2010)

According to a recent study in the journal Nature Plants, around 95 percent of wild relatives of agricultural crops are insufficiently safeguarded in gene banks around the world. These crop wild relatives (CWR) are closely related to domesticated plants and have become increasingly important in efforts to protect crops against threats like drought, pests, and disease.

A team of researchers affiliated with the International Center for Tropical Agriculture (CIAT), the Global Crop Diversity Trust, and the Royal Botanic Gardens, Kew examined 1,076 taxa related to the world’s 81 most important crops. Their survey involved collecting information from biodiversity, herbaria, and gene bank databases.

They found that 70 percent of these CWR were poorly represented or not represented at all in gene banks, including relatives of banana, cassava, wheat, and sorghum. Nearly all of these species lacked a full geographic and ecological diversity coverage. The researchers identified regions in urgent need of collecting focus to preserve wild diversity, including the Mediterranean, the Near East, Asia, and Southern Europe.

Fig.2. Arachis duranensis, a crop wild relative of the peanut
(Credit: Misco, 2009)

Wild Plants in Danger

This study is possibly the most comprehensive list of gaps in CWR collection and highlights the need to understand these species. Close crop relatives often have traits that could be valuable for plant breeders to create pest-resistant varieties or to protect against increasing temperatures. For example, several wild relatives of the economically important sunflower are more tolerant to acidic or alkaline soils. Other relatives grow in very large ranges, suggesting resilience to changes in environmental conditions.

Efforts to capture the sheer diversity of wild relatives of crops are often hampered by a lack of funding and infrastructure to deal with these seeds. Additionally, the study’s authors cited concerns over biopiracy, which relate to the equitable use of genetic resources and collection of native seeds. Unfortunately, gene banks may be the only sanctuary left for certain species that are threatened by habitat loss and invasive species.

Fig.3. The Millennium Seed Bank Project buildings in England, 
which hold the largest wild plant seed bank in the world 
(Credit: David Iliff, License: CC-BY-SA 3.0)

Conservation for CWR

The dangers facing CWR are closely linked with ongoing research on how climate change might affect food supply. A recently published study in Nature Climate Change focused on a region in Brazil that supplies 10 percent of the world’s soybeans. The study estimated that if past patterns for production and temperature hold in the future, an average increase of 1℃ could reduce soy and corn production by 9 to 13 percent. Not all crops will respond to climate change in a similar fashion - warm summers bode well for wine growers in the short term - but growing populations and extremes in temperatures and precipitation could strain our food supply.

Fortunately, the Kew Millennium Seed Bank in the UK and the Global Crop Diversity Trust in Germany have project agreements to collect and store CWR seeds from seven countries and have negotiations underway with 26 other countries. National efforts like the Plant Germplasm Introduction and Testing Research Unit within USDA’s Agricultural Research Service and other inventories around the world are working closely with the Global Crop Diversity Trust to preserve locally important crops. This gap analysis serves as a baseline for what needs to be collected and where. With increasing strains to our food supply system, these wild relatives offer hope for sustainable and diverse crops.


References
Castañeda-Álvarez, A., et al. (2016, March 21). Global conservation priorities for crop wild relatives. Nature Plants: 16022. Doi: 10.1038/nplants.2016.22

Gewin, V. (2016, March 21). Wild relatives of key crops not protected in gene banks, study finds. Science. Doi: 10.1126/science.aaf4018

Kantar, M. B., et al. (2015, October 08). Ecogeography and utility to plant breeding of the crop wild relatives of sunflower (Helianthus annuus L.). Front. Plant Sci., vol. 6 (Article 841). Doi: 10.3389/fpls.2015.00841

Glossary

gene banks
Biorepositories that preserve genetic material. Examples of genetic material include seeds, sperm or eggs, tissue samples, and coral fragments.
Crop Wild Relatives (CWR)
Wild plants related to economically important and cultivated crops