Humanity's desire for high-yielding crops is as old as civilization itself.

In China, this is best illustrated by the fact that 41 of the nation's 56 ethnic groups have their own myths about the creation of fertile seeds, according to the Chinese Academy of Social Sciences' Institute of Ethnic Literature.

The Dong ethnic group believes that seeds were bestowed by deities showing compassion to mortals, while according to the folklore of the Wa ethnic group, they were spat out by a world-devouring snake slain by the Heaven God.

Now, modern technologies have produced quality seeds from an equally fantastic source－outer space.

These seeds have produced a range of crops, from tomato vines that can sprawl across 150 square meters of land and bear 10,000 fruits, to giant black-eyed pea sprouts measuring nearly a meter long, according to the China Aerospace Science and Technology Corp, or CASTC.

This progress has been achieved through space-induced mutation breeding, also known as space mutagenesis.

In China, hundreds of varieties of space crops have been planted nationwide. They are a key pillar supporting food security, as well as an innovative approach to improving farmers' yields and combating rural poverty.

The International Atomic Energy Agency, or IAEA, defines space-induced mutation breeding as a technique in which seeds are taken into space, where they are exposed to strong cosmic rays－high-energy particles traveling close to the speed of light－as well as other conditions such as vacuums, microgravity and low levels of geomagnetic interference.

This method does not involve transferring genes from one organism into another, as is the case with genetically modified food. Instead, it generates random but potentially useful traits by using a plant's genetic material, mimicking the natural process of spontaneous mutation, albeit at a significantly accelerated rate, the agency said.

Since the 1920s, seeds have been exposed to radiation or chemicals by scientists to induce greater yield, stability and adaptability to climate change. More than 2,500 varieties of plants bred through mutagenesis have been officially released, according to the Food and Agriculture Organization, a UN agency.

Space is a new setting in which to conduct this time-tested breeding method, and the IAEA, FAO and the World Health Organization consider space crops safe to consume, as long as they pass rigorous testing and approval processes.

In the 1960s, the United States and the Soviet Union carried out space mutation breeding for scientific research and to make living in space more sustainable for astronauts.

"However, no country has turned this into a full scale, modern agricultural industry like China has done," said Guo Rui, director of the Shaanxi Province Engineering Research Center for Plant Space Breeding.

In 2018, China's space breeding industry had a direct economic impact of more than 200 billion yuan ($29.9 billion at today's exchange rate) and produced over 1.3 million tons of food, according to CASTC.

More than 200 space plant and fruit varieties, including rice, wheat, maize, soybeans, cotton and tomatoes, have been approved for planting by regulatory bodies, with over 3,000 more in development. In 2018, the total plantation area for space crops approved in China reached more than 2.4 million hectares－roughly the size of the state of New Hampshire in the United States.

Guo said, "China is the world leader in breeding plants in space, partly due to the country's rapid rise as a world space power.

"But more important, we are pursuing this technology vigorously because we need to solve many strategic challenges, such as feeding a populous nation with limited arable land supply, as well as modernizing our agricultural sector and ensuring food security."

New traits

Chengcheng county in Shaanxi province is home to Piperis dahongpao, a variety of spice commonly known as big red robe peppercorn that is widely employed in Chinese cuisine.

The spice has been used since the Han Dynasty (202 BC-220 AD) for cooking, medicine, rituals and even for palace decorations, according to the Kunming Institute of Botany, Chinese Academy of Sciences.

However, it has a notoriously low yield and is difficult to harvest, as the plant stems are covered with sharp thorns. For centuries, it was considered a "tribute spice" enjoyed only by the privileged, the best-known being Empress Dou of the Han Dynasty, who decorated her chamber with the condiment to signify fertility and prestige.

It is still not cost-effective to produce this spice. Guo said, "A laborer can only pick about 7.5 kilograms of this peppercorn per day, and after it is dried in the sun, less than 2 kg is left."

In 2016, Guo and his team sent some of the spice seeds into orbit for 12 days aboard the Shijian-10 recoverable science satellite.

The team was aiming to create a new variety of peppercorn with stronger resistance to wind and disease, but it discovered something far more exciting－the thorns on the stems had disappeared.

"Generating unexpected new traits is one of the main features of space-induced mutation breeding," Guo said.

He added that while scientists have used chemicals and radiation, including gamma rays and X-rays, for decades to induce mutation in laboratories, space offers new conditions, such as microgravity, vacuums, extreme cold and a diverse range of cosmic rays.

Breeding labs can now effectively produce some of the conditions experienced in space, but replicating them all is impractical and costly, Guo said. Moreover, mutating seeds in space may produce surprising new traits more successfully than in a lab. "Space is like a super-lab for breeding new plants," he added.

Liu Luxiang, deputy director of the Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, said during a public lecture last month that while space mutagenesis is a promising technology, the way in which space affects plant seeds is extremely complex and difficult to control and evaluate.

"Only a tiny fraction of seeds exposed to space will have mutations, and not all of them will produce desirable traits," he said. As a result, sending seeds into space is merely the start of creating a new variety. The bulk of the research is about growing the returned seeds in different testing fields over several generations to produce a crop that can reliably showcase desirable traits.

Scientists sometimes cross-breed space crops with other varieties to create hybrids that inherit favorable traits from their parents. Liu said. "Ground tests can be a very arduous and complicated process that typically takes at least four years to complete," he added.

Guo said his thornless peppercorn is undergoing field tests, and it is hoped that more traits can be changed to enable it to be harvested by machine, greatly increasing the yield and raising farmers' earnings. In addition to spices, crops such as peonies, wolfberries and seaberries are being improved by using space technologies.

Guo said, "Space crops have played a major role in alleviating poverty, developing local economies and creating unique products.

"Scientists' role is to enhance basic research in seed selection and breeding, and facilitate the integration of space plant breeding technologies with modern agriculture to better safeguard our nation's long-term food security."

Poverty relief

Nyemo, meaning "ear of grain" in the Tibetan language, is a county located at the heart of the Qinghai-Tibetan Plateau that is home to Tibetan incense and has a rich history of farming and cultivation.

However, decades of environmental degradation left land in the remote county barren, with more than 5,100 villagers living in poverty in 2016, according to the Office of Beijing Municipal Leading Group for Poverty Reduction Cooperation and Assistance.

To reduce poverty and restore land fertility, the Beijing municipal government, in collaboration with the county authorities, introduced space plants to the locals.

Companies also invested in computerized greenhouses in the county to grow peppers, tomatoes, cucumbers, watermelons and nine other crops that can survive on the arid plateau. Last year, sales of the space produce totaled more than 400,000 yuan, with over 25 percent of the earnings distributed among 98 poverty-stricken families, the office said.

Phuntsok Tsering, a villager living in the county, said,"Not only have I learned new skills at the space plant greenhouses, I have found a way to get rich and have also taken on an apprentice."

Through personal tutoring, he learned from scientists how to grow tomatoes using mineral nutrient solutions, rather than soil. "I now earn at least 3,000 yuan per month and life is so much better than before," Phuntsok Tsering said.

Similar success stories have been reported nationwide. As of last month, CASTC had helped eliminate poverty through space crop agriculture and other methods in 21 villages in nine provinces. For example, in Yang county, Shaanxi province, some 30,000 people escaped impoverishment.

Chen Zhiqiang, director of the National Engineering Research Center of Plant Space Breeding, said high-quality rice varieties induced by space mutation have played a major role in safeguarding national food security and alleviating poverty in Guangdong province.

In 2003, China approved its first space rice－Huahang-1－which was planted on 333,300 hectares of land in the south of the country. From 2010 to 2012, the crops created by the center covered a total plantation area of more than 621,360 hectares, with farmers' earnings rising by nearly 1 billion yuan as a result.

Huahang simiao, a disease-resistant space rice variety, has been especially popular among farmers in Boluo county, Guangdong. It has a high yield and is highly flavorsome－factors that help farmers sell it for 250 yuan per 50 kg, which is 150 yuan more than other varieties, according to the local agricultural bureau.

Chen said, "Seeing the smiles of my farmer friends when they have a good harvest is the most satisfying reward to me."

Developing industry

On Aug 5, 1987, China launched its first seed samples into space, opening a new chapter for the nation's space-induced mutation breeding. Since then, Chinese scientists have sent more than 30 batches of seeds into space, using a range of satellites and spacecraft, according to CASTC.

However, apart from the Shijian-8 recoverable science satellite launched in 2006, which was designed specifically for breeding plants in space, all other such missions employed instruments for other purposes, severely limiting the quantity of seeds that could be sent into orbit.

Wang Weidong, deputy general manager of Azspace, an aerospace company based in Beijing that focuses on spacecraft re-entry technologies and services, said, "Cost and accessibility are some of the biggest bottleneck issues for breeding plants in space."

Not all seeds sent into space generate mutations, so scientists send multiple batches into orbit to increase the success rate. However, the cost-effectiveness of such missions is "hard to manage" due to a shortage of inventory and retrievable space instruments, she said.

"A prosperous commercial spaceflight industry can provide more launch opportunities and services, reducing the cost of space travel and greatly lowering the entry barrier for breeding plants in space. This will enable such breeding to become a more accessible and mainstream technology," Wang said.

Zhang Jianwei, a researcher at the Institute of Isotope Research, Henan Academy of Sciences, said that to make a new wheat variety using mutation breeding, scientists would typically need 3,000 seeds, which can weigh about 135 grams.

In China, it costs about 3,000 yuan to send 1 gram of material into space, so the bill for putting a sample package of seeds into orbit would be 405,000 yuan, Zhang said.

"Space is an interesting platform for mutation breeding, but as this may not be very cost-efficient, many researchers still prefer the far cheaper, more accessible and time-tested method of using labs," he said.

Wang said scientists must consider the cost and benefits of sending seeds into space, along with limited budgets and a high degree of uncertainty.

"If China's commercial space industry can grow to the point where cheap and available flights are possible, it will push breeding plants in space to new heights," she said.

Zhang said that because space technology is greatly admired, another major challenge lies in space crops being excessively hyped and commercialized, which could create unrealistic public and market expectations.

Chen said, "Only seeds that help farmers improve their productivity and yield can be considered successful."

Guo said enhancing public education and understanding about breeding plants in space, especially the safety aspects, is crucial for the image and development of the technology.

As costs are likely to remain very high for the foreseeable future, he said China's space breeding community should focus more resources on seed selection and groundwork to make the most of the limited time seed samples spend in space.