People have been saving seeds for some 10,000 years, though the practice has become threatened due to recent changes in agricultural practices. To ensure the future of our crops, it's now all the more important to bank our seeds.
Save the Seeds
Banking on Reproduction
Sunday, May 8, 2011
The development of agriculture stems from when people discovered the great power of saving seeds. It’s been for some 10,000 years that people have been carefully collecting and saving seeds from a crop one year so that they could be used to plant another crop the following year.
But agricultural practices have dramatically changed over the last century, and this foundational act of seed saving has nearly become a lost art over the past couple decades. Seeds are increasingly not being saved from year to year, as traditional, local crops are being replaced by identical, new crops in fields all over the world. This threatens tens of thousands of plant species with extinction and is causing many to once again recognize the importance of saving seeds, not just from local fields, but from all around the world.
The history of saving seeds: Saving seeds is an essential component of agriculture itself. Originally, it’s thought that people collected seeds from edible wild plants and learned how to grow these plants in a more controlled fashion so they didn’t have to solely rely on gathering food from the wild plants. By taking seeds from the most desirable plants (those with the largest fruits or other edible parts, or that simply grew best in the local area), people over time came up with domesticated crops that were an improvement upon their wild relatives—an improvement at least as far as the people who wanted to eat them were concerned. Over thousands of years, this selection process led to the amazing array of crops we have today, with people historically consuming over seven thousand plant species in their diets.
But over the last couple decades farmers have increasingly broken from this time-honored practice of saving their seeds, instead buying them commercially. Usually these commercially available seeds produce plants with particularly alluring traits, such as bearing more fruit or being more robust. However, in many cases the plants from these commercial seeds do not breed “true” from one generation to the next: The hybrid seeds produce plants that are genetically uniform the first generation, but their “offspring” don’t typically retain their vigor or desirable traits. Consequently, farmers become dependent on buying new seeds each year.
As if such genetic deterioration weren’t enough, it’s also in most cases illegal for farmers to save the seeds of plants grown from commercial seeds, or even for their neighbors, who didn’t purchase the seeds, to accidentally have some seeds land on their property and sprout.
This matter received attention in The Santa Barbara Independent last month, as organic farmers from Santa Barbara, along with a total of 60 others from around the country, filed a lawsuit against Monsanto, the global leader in supplying genetically modified (GMO) crop seeds. Some of Monsanto’s most famous seeds are “Roundup ready,” creating plants resistant to the broad-spectrum herbicide Roundup, so that farmers can simply spray with this herbicide to eliminate weeds while the crops are spared. It’s illegal for farmers who did not purchase the GMO seeds to grow them in their fields, but the GMO crops show up in fields whose owners claim they did not use Monsanto seeds. In the U.S. alone, despite their bounty and utility, problems with Monsanto crops have affected some tens of thousands of farmers. Contamination by GMO crops is just one more reason why people are focusing greater effort on creating seed banks.
More reasons to bank seeds: Long before the development of widely available commercial crop seeds, the Russian biologist Nikolai Vavilov (1887-1943) first thought up, and created, a large seed storage bank. Vavilov gathered seeds globally, traveling for decades over five continents and collecting a wider variety of seed species than anyone else had ever amassed. His research was so important to his group that, during the Siege of Leningrad in World War II, an assistant of his died of starvation rather than eat the edible seeds in their seed storage facility in Leningrad.
Why is storing seeds so important? A major reason is to prevent species and strains from becoming extinct. As discussed above, more and more farming operations have switched from planting their traditional, local crop varieties to using the relatively few varieties that are commercially available. Consequently, farmers as a group are no longer saving and maintaining the seeds of the old varieties. Additionally, societal upheaval from wars or natural disasters can have a similar effect. It’s hard to know exactly how many crop varieties have already been lost, but some believe that number may be in the thousands. Species diversity is most certainly being lost as well: Humans once had around 7,000 plant species in their diets, while today we grow less than 150, and only 12 make up the majority of what we actually eat. And once these species and varieties are gone, they’re gone forever.
One might think that the loss of some crop varieties isn’t such a terrible thing. Surely the new varieties we’ve developed, and focus on using today, are an improvement upon the old ones, so what’s to miss? These new varieties may seem “better,” in that they may produce more fruit, or resist certain insects or diseases, or tolerate harsher climates, but for an organism to truly stand the test of time it needs diversity in its gene pool.
It’s hard to predict what challenges an organism will face in the future that it hasn’t encountered yet. For example, when a strain of deadly flu initially contacts a population of people, some people will be more susceptible to infection than others. We have this varying range of vulnerability to infection in large part because our genetic pool is diverse. But if we didn’t have this diversity, and everyone was susceptible to the new viral strain, it could wipe out the human race.
It’s the same with crops. By focusing on growing one variety, or even just a few varieties, of a crop, we run a great risk of having an entire crop succumb to devastation, such as we saw with the near-extinction of the Gros Michel bananas due to the Panama disease (a fungal wilt), which is now wreaking havoc on the Cavendish bananas, which are the sole type of banana that most of us eat. It’s essential to maintain a large amount of genetic diversity to adapt to all kinds of unanticipated changes in the future.
Researchers working at seed banks not only want to maintain this genetic diversity in crops, but they also use it to create new varieties that can handle current and unforeseen agricultural challenges. This is actually the primary reason Vavilov collected all those seeds; he was determined to breed different varieties together to improve upon existing crops. The main difference between these efforts and the ones generating commercial hybrid seeds is that the former aims to create a wide range of “true breeding” varieties that are ready to deal with all kinds of environmental challenges. For example, some varieties may have the ability to withstand climate change, such as droughts or heat, or changes in soil conditions, like increased salinity. Crops can even be bred that require less land or water, improving the agricultural footprint needed to feed people and saving forests from deforestation.
How the banks work: Today, there are about 1,400 seed banks in over 100 countries globally. It’s estimated that there are some six million samples of seeds in all of these banks, but due to overlap in the seed types collected, only around one to two million are distinct.
How do these “banks” store all this reproductive material? The seeds are collected in fields by researchers, or sent in through correspondence. Some 90 percent of plant seeds store well in very cold, dry conditions, specifically from about 14 to -4 degrees Fahrenheit. Storing each sample in its own sealed, airtight container this way is a practical and economical way to keep viable reproductive material from the vast majority of plants globally.
But while this seed storage method works well for most plants, it doesn’t work for all. Some seeds, known as recalcitrant seeds, die if exposed to cold temperatures (below 50 degrees Fahrenheit) or if they’re dried out. Many tropical and subtropical plants have recalcitrant seeds; one such plant near and dear to Southern Californians is the avocado. Because it is so difficult to store recalcitrant seeds long-term, to keep these genetics active in the seed banks other reproductive plant parts or even complete plants must be maintained. But like most things in biology, seed storage isn’t black or white; some seeds tolerate a range of temperature and desiccation storage conditions in between these two seed groups.
In ideal storage conditions, some crop seeds, such as peas, may last 20 to 30 years, while others, including many types of grains, can still be viable after hundreds of years of storage. Outside of the carefully controlled conditions in storage facilities, researchers discovered seeds from a lupine plant (Lupinus arcticus) in Canada, beneath permafrost, that were thought to be 10,000 years old and that still, amazingly, produced healthy plants, testifying to the ability of seeds to withstand the tests of time. It’s thought that seeds’ decreased viability over time is due not to using up food reserves, but to enzymes ceasing to function that are necessary for the seed to use these reserves, along with DNA repair mechanisms breaking down. To ensure that viable seeds are kept in the seed banks, researchers continually take a few seeds from stored samples, grow them up, collect the new seeds, and put these back into storage.
The Svalbard Global Seed Vault As an extra backup measure for all seed banks, the Norwegian Svalbard Global Seed (SGS) Vault was built. Opened in 2008, SGS has the capacity to store duplicates of all the unique seed samples from seed banks around the world; it can hold over four million different seed samples, and all depositors retain rights over, and access to, their seeds. This construction is especially important because up to half of the seed banks in developing countries are threatened by political instability or natural environmental problems, and it is difficult for many third world countries, which have the most plant diversity, to afford seed-bank facilities. Located on the Norwegian archipelago of Svalbard, just 600 miles from the North Pole, SGS is under a permafrost mountain, so that even if it lost power the seeds would remain below 26 degrees Fahrenheit. And walls over three feet thick with steel-reinforced concrete protect it from other natural disasters, ensuring the continuation of our 10,000-year-old practice of seed saving.
How to help: While the creation of the Svalbard Global Seed Vault and the 1,400 other seed banks in the world are tremendous accomplishments, it’s important to keep these efforts going, especially in the face of global climate change and societal upheaval. The biggest challenges seed banks in general face are a lack of funding and resources. With the amazing power of the Internet, it usually doesn’t take too much searching to find relatively local seed banks and learn about what they’re doing.
For example, California has a seed bank associated with the California Rare Fruit Growers organization. And if you’re a gardener, you can help maintain rarer plant varieties (which can be bought from catalogs) by growing them in your garden and saving your own seeds. Local seed exchanges are fairly common; usually anyone can join in and swap some seeds, continuing an agricultural tradition that’s been around for thousands of years.
For more on seed saving, see the book Saving Seeds by Bonwoo Koo, Philip Pardey, Brian Wright, and others, the Manual of Seed Handling in Genebanks by N. Rao, Jean Hanson, M. Dullo, Kakoli Ghosh, David Nowell, and Michael Larinde, the book Ecology of Soil Seed Banks by Mary Leck, V. Parker, and Robert Simpson, the Web sites for Genetic Resources Action International (GRAIN), the International Seed Federation, the International Seed Saving Institute, or the Svalbard Global Seed Vault, or Wikipedia’s articles on Seed saving or Seedbank.
Biology Bytes author Teisha Rowland is a science writer, blogger at All Things Stem Cell, and graduate student in molecular, cellular, and developmental biology at UCSB, where she studies stem cells. Send any ideas for future columns to her at email@example.com.