Importance of Genetic Diversity in Agriculture

Chase James Krug
Jul 23, 2018 · 5 min read
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Diversity of Crop Species

World Vegetable Center houses the largest public collection of vegetable germplasm in the world. Germplasm are living genetic resources such as seeds or tissue that are maintained for their use in plant breeding. The collection safeguards vegetable crop genetic diversity that may be useful in the future. Jack Harlan, an agronomist and botanist once said, regarding the biodiversity within crop species (genetic diversity), “stands between us and catastrophic starvation on a scale we cannot imagine.” According to the United Nations Food and Agriculture Organization, 75% of all crop genetic diversity has been lost since the previous century, primarily due to changes in the agricultural food system which values uniformity. Of the remaining 25%, one third is expected to become extinct by 2050. Genetic diversity is the total number of genetic characteristics in the genome of a species. Curators of crop genetic diversity include seed banks, gene banks and agricultural research institutions that house collections of seeds and propagative material. These collections house the world’s tools to cope with new challenges within our food system. Agricultural genetic diversity is imperative to provide a robust food security system capable of adapting to pest and environmental stressors. Genetic diversity allows agricultural plant and animal breeders to adapt to changing variables.

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According to the International Development Research Center, the global food supply “depends on about 150 plant species. Of those, just 12 provide three-quarters of the world’s food. More than half of the world’s food energy comes from a limited number of varieties of three “mega-crops”: rice, wheat, and maize”. The global food supply is increasingly under threat from climate change, world population growth and the introduction or range expansion of disease and insects. Genetic diversity is needed to safeguard potentially vital traits that could be used to combat an unexpected future pest or adapt to the needs of the world’s food supply. Plant breeders utilize genetic diversity to create improved crop varieties with traits such as yield, pest resistance and environment stress.

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Left: Rice, Middle: Corn, Right: Wheat

To adequately store genetic diversity, it is important the germplasm collections are well maintained, and backup collections are created to ensure its survival in case of a natural disaster or political unrest. Seeds and plant tissues are stored in-situ, meaning stored in a controlled environment such as cold storage or tissue culture facility. In-situ storage requires a relatively small space to accommodate a large amount of material. While propagative material from plants such as trees, shrubs and clonally propagated crops are stored ex-situ, meaning crops are preserved in an outside environment. Ex-situ storage requires a lot of space and are vulnerable to pests, natural disasters and human nature. These crops are the most at risk for extinction and most collections remain largely unstudied.

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Gene Bank

There are partnerships with private and governmental seed bank institutions to preserve crops that can be stored in-situ for long periods of time in the form of seeds at the Svalbard Global Seed Bank located north of the Arctic Circle. The Svalbard Global Seed Bank acts as a safety deposit box which allows institutions to safety deposit and withdraw their backup seed collections in case their main collection is lost or severely damaged. There are some regional and national partnerships regarding ex-situ crops in the United States and abroad, but international partnerships are difficult to conduct due to plant quarantine restrictions and the possible importation of pests. Until new efficient methods are devised to limit the transfer of pests, there is a need for increased funding and effort to create more backup collection sites spread throughout the world. It is important that the remaining uncollected crop genetic diversity from wild crop relatives, unique plant populations with low representation in gene banks and minor crops located in remote regions of the world, are collected and preserved before they go extinct. Wild crop relatives are the ancestors of our domesticated crops. They may contain important genetic traits, which may have been lost during the domestication process. Traits such as drought or pest resistance will be crucial in adapting to climate change. Many wild crop species are at risk for extinction due to habitat destruction or the encroachment of urban sprawl. Unique plant populations that are currently underrepresented in gene banks need to be collected due to current material limited to a few individuals, which does not adequately represent all the genetic diversity within that population. These populations are located in small pockets, which are extremely vulnerable to extinction due to pests or human activity.

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The United States Plant Germplasm System currently houses almost 580,000 accessions of crop material. In the last 8 years it has gained almost 60,000 more accessions. An accession is an individual cultivar or variety of a crop. During the same period, the budget has remained relatively stagnant. With such a large increase in the amount of accessions being curated, resources devoted to important programs such as plant expeditions, infrastructure, regeneration, and development of improved conservation practices are strained. Genetic diversity is an important resource that needs to be properly collected and conserved for future generations.

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Potato Diveristy

Genetic diversity will play a crucial role in the development of crops adapted to climate change and the production of food for the growing world population. To ensure these resources are available to plant breeders in the future, more public funding in seed banks and agricultural institutions is needed. The public needs to be informed of the importance of our genetic resources for the sake of improving the global food system.

Bibliography

“Conserving plant genetic diversity crucial for future food security — UN | UN News.” United Nations, United Nations, 26 Oct. 2010, news.un.org/en/story/2010/10/357072-conserving-plant-genetic-diversity-crucial-future-food-security-un.

“Facts & Figures on Food and Biodiversity.” IDRC — International Development Research Centre, International Development Research Centre, 12 Feb. 2018, www.idrc.ca/en/article/facts-figures-food-and-biodiversity.

“Germplasm.” Wikipedia, Wikimedia Foundation, 3 July 2018, en.wikipedia.org/wiki/Germplasm.

Kyte, Rachel. “Crop Diversity Is Key to Agricultural Climate Adaptation.” Scientific American Blog Network, Scientific American, 18 Aug. 2014, blogs.scientificamerican.com/guest-blog/crop-diversity-is-key-to-agricultural-climate-adaptation/.

“Why Is Crop Diversity Important?” Crop Trust, www.croptrust.org/our-mission/crop-diversity-why-it-matters/why-crop-diversity-important/.

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