In 1956, fourteen young scientists from the Chinese Academy of Sciences packed their bags and left Beijing, boarding a train bound for Shaanxi.
As the train chugged along, a fellow traveler was surprised to see one tall, bespectacled youth carrying a backpack full of grass roots. When asked about it, he simply replied, "The northwest might need them."
These youths were answering the call to support the development of Northwest China, and they were headed to Yangling, Shaanxi, to become the backbone of the newly established Northwest Institute of Agriculture and Biology of the Chinese Academy of Sciences (later renamed as the Institute of Soil and Water Conservation of the Ministry of Water Resources of the Chinese Academy of Sciences, hereinafter referred to as the Institute of Soil and Water Conservation).
Among them was a young man named Li Zhensheng, who hailed from the Institute of Genetics and Developmental Biology of the Chinese Academy of Sciences (formerly known as the Institute of Genetics and Developmental Biology, hereinafter referred to as the Institute of Genetics and Developmental Biology). Little did he know that the grass roots in his backpack would, after 25 years of painstaking research, give birth to the first disease-resistant and high-yielding distant hybrid wheat variety, "Xiaoyan 6," effectively curbing the spread of rust disease and ushering in a new era of distant hybrid wheat breeding in China.
In 1956, during the early years of the People's Republic of China, the per capita grain production was only about 306 kilograms, far below the international food security line of 400 kilograms per capita. Ensuring that the people had enough to eat became a top priority for the nation.
At that time, wheat rust disease was rampant in the Yellow River Basin of China, causing wheat yields to decrease by over ten billion kilograms annually, equivalent to one-twentieth of China's total grain production at the time, exacerbating the already dire food shortage in China. Premier Zhou Enlai proposed treating wheat rust disease control as if it were combating a human epidemic.
Wheat rust disease posed a significant threat, with its summer spores bursting and releasing large amounts of rust-colored spores that could spread throughout a field within days. Once infected, wheat could suffer yield losses of 30% to 50%, or even total crop failure.
Moreover, using the common breeding method of crossing foreign disease-resistant wheat with local varieties to develop resistant new strains took about eight years. However, wheat rust disease could adapt to these "inbred" new strains and render them susceptible again in just five and a half years on average.
Li Zhensheng arrived in the Guanzhong Plain and witnessed the terrifying extent of wheat rust disease. "Walking through the wheat fields in black pants, they would turn yellow. Some farmers cried at the sight," he recalled.
How could the fatal flaw of breeding speed failing to keep up with pathogen mutation be remedied? Li Zhensheng pondered over this problem.
Born in the rural area of Zibo, Shandong Province, Li Zhensheng experienced poverty and famine in his youth. Years of droughts had depleted the village's elm leaves and bark, and even onion roots and garlic husks were used as food. This made him deeply aware of the value of food.
In his sophomore year of high school, Li Zhensheng dropped out to find work in Jinan to alleviate his family's burden. At that time, an advertisement for "free board and lodging" in Shandong Agricultural College caught his attention. He successfully applied and embarked on the path of wheat breeding.
After graduating, Li Zhensheng was assigned to the Institute of Genetics and Developmental Biology of the Chinese Academy of Sciences. Although he was initially disappointed not to be doing genetic breeding research, being assigned to the cultivation department, dealing with various types of forage, he could not have foreseen that this seemingly unrelated work would lead him to pioneer a new field of wheat genetic breeding.
Seeing the grass roots he brought from Beijing, Li Zhensheng conceived a bold idea: could he breed a wheat variety with strong disease resistance by crossing forage grasses with wheat?
"Wheat, after thousands of years of cultivation, is like a flower in a greenhouse, gradually losing its disease-resistant genes; whereas wild grasses in nature have been selected layer by layer, eliminating individuals without disease resistance, making them an excellent gene pool," Li Zhensheng thought. If he could pass on the disease resistance of wild grasses to wheat, wouldn't that significantly increase wheat's disease resistance?
This idea gained support from botanist Wen Honghan and plant pathologist Li Zhenqi.
However, wheat had evolved over tens of thousands of years. Li Zhensheng was unsure of the likelihood of success and how long it would take.
In fact, Chen Shaoyang, a graduate of the Northern Jiangsu Agricultural College, had arrived at the Institute of Soil and Water Conservation before Li Zhensheng. She attempted to transfer the perennial nature and disease resistance of grass barley to wheat but found no changes in wheat traits after two years of research.
After reviewing international research literature, Li Zhensheng believed that as long as the method was correct and perseverance was maintained, this path was feasible. He planted the grass roots he carried in the courtyard of the Institute of Soil and Water Conservation, set up simple semi-underground soil greenhouses for seed reproduction, and quickly led a team of young scientists, including Chen Shaoyang, Li Rongling, Liu Guanjun, and others.
Crossing distantly related forage grasses with wheat posed three major challenges: first, they were not easily compatible for hybridization; second, the hybrids were sterile, like mules bred from horses and donkeys, and had no breeding ability; third, the offspring exhibited "crazy segregation," making it difficult to maintain disease resistance traits.
However, Li Zhensheng and his team faced these challenges head-on. Initially selecting twelve species of forage grasses for crossing with wheat, only three were successful. Among them, the progeny of tall wheatgrass grew the best, so they made it the focus of their research. Tall wheatgrass flowered later than wheat, so they used artificial lighting to adjust its flowering period, causing it to flower two months earlier and successfully pollinate; when the hybrid varieties failed to germinate, they squatted in the fields to inspect each wheat plant, finding hybrids with normal male and female flowers and repeatedly crossing them with the parental lines; sometimes a hybrid looked promising, but the next generation looked completely different, so they repeatedly reevaluated and selected... After eight years of research, the ideal wheat variety still hadn't emerged.
"Casting the net too wide with distant hybridization"..."A waste of funds and time"... Criticisms poured in, plunging the research team into a dilemma.
Fortunately, at the outset of their distant hybridization research, Li Zhensheng remembered a philosophical discourse by Ai Siqi when he first arrived at the Chinese Academy of Sciences. They adopted a "two-pronged approach," simultaneously conducting research on hybridization between wheat varieties, thus not putting all their eggs in one basket.
This combined approach of near and far-reaching goals proved invaluable. Initially, some wheat varieties bred through inter-varietal hybridization were promoted in Shaanxi, allowing the distant hybridization research to continue.
In the summer of 1964, continuous rain persisted until just over a month before the wheat matured. On June 14th, the weather suddenly turned sunny, and almost all of the over 1000 hybrid offspring of wheat dried up within a day - their leaves were still green, but the plants had withered. Only one plant withstood the intense sunlight, maintaining its golden hue.
This hybrid variety, which escaped drying up, gave Li Zhensheng's research team great confidence. Known as "Xiaoyan 55-6," this material was both heat and disease-resistant, becoming the "ancestor" of the later widely promoted "Xiaoyan 6."
"In scientific work, there are necessities within accidents; it depends on whether you can seize the opportunity," Li Zhensheng remarked about this "accident" and "opportunity." At that time, he inspected the fields every day, so attentive that he could discern which material was growing where without even looking at the records. Eventually, he keenly observed subtle differences.
"Xiaoyan 55-6" was just an initial success, and the road to applying distant hybridization varieties in production was still long and arduous.
In 1965, Li Zhensheng led the research team to the newly established Northwest Institute of Botany, Chinese Academy of Sciences (later merged into Northwest A&F University). In addition to the institute's seven or eight acres of experimental fields, he also managed to open up 30 acres of experimental fields in Guancun nearby to conduct research on distant hybridization breeding. Graduates from Hebei Agricultural University, Mu Sumei, and Zhong Guanchang, were assigned to the institute to work with Li Zhensheng.
Mu Sumei recalled that it was a 10-mile journey from the Northwest Institute of Botany to the experimental fields in Guancun. At that time, the entire research team had only one bicycle. During planting and pollination seasons, Li Zhensheng and his colleagues would carry steamed buns and walk from the institute to Guancun. During the wheat sowing season in October, if it rained continuously, the road would become impassable. Their rain boots would get stuck in the mud, accumulating mud and making walking increasingly difficult.
When farmers sow wheat, they carry baskets made of woven branches on their arms, reaching in to grab a handful of seeds and scatter them in the newly turned furrows, completing the task. However, the process was different for the research team - they had to plan the planting rows for each material meticulously. Some rare materials even had to be sown grain by grain, with a label inserted for each row of materials.
Regarding the planting process, Zhou Hanping, a senior technician at Northwest A&F University, recalled experiencing Li Zhensheng's "anger" shortly after joining the research team.
Once, it rained continuously for half a month, and to avoid affecting the later stages of the research, they planted in the rain. The field became muddy, and Zhou Hanping's work was a bit rough. Unexpectedly, Li Zhensheng noticed his carelessness.
"No matter how heavy the rain is, we must follow the rules," Li Zhensheng, who was usually good-natured, said sternly to Zhou Hanping. "Only under very strict conditions can we observe genetic differences." With that, Li Zhensheng demonstrated it himself. This incident deeply educated Zhou Hanping, and he became very meticulous in subsequent experiments.
Not only planting but also harvesting, carting, and threshing were all time-consuming tasks done by the research team themselves.
During wheat harvesting, the scorching heat made the leaves lose moisture, drooping one by one. They endured the heat to pull out the distant hybrid wheat and transport it back to the Northwest Institute of Botany.
Since the precious materials couldn't be threshed mechanically, they squatted on the ground, using a small rubbing board to rub the wheat spikes back and forth, letting the grains fall into the box beside them. Then, they used a small fan to blow away the husks, inspected the quantity, color, and plumpness of the grains, and finally packed them into small leather bags, labeled with numbers.
Time flew by, seasons changed. In the experimental fields of Guancun, simple houses, warehouses, and a two-story building were gradually built, saving them the daily trip of 20 miles to check on the wheat.
In 1970, after six years of repeated hybridization and backcrossing, Li Zhensheng's research team obtained an excellent new material named "Xiaoyan 96" - the "father" of "Xiaoyan 6." This material had excellent characteristics such as disease resistance, early maturity, resistance to dry hot winds, and high quality. Using it as a parent for hybridization finally yielded the first generation of "Xiaoyan 6" the following year.
However, at this time, "Xiaoyan 6" still faced the problem of unstable fertility. It wasn't until 1977 that the research team used lasers to irradiate the hybrids and repeatedly bred them to the seventh generation, finally obtaining an exceptionally superior individual plant - the original strain of "Xiaoyan 6" widely planted in the Huang-Huai-Hai region later.
"We treated this individual plant differently, sowing its seeds evenly in a small area, and the population traits were consistent," Li Zhensheng said.
Under limited irrigation conditions, this batch of seeds yielded over 350 kilograms per mu, a 17% increase compared to the control varieties. These achievements earned the Wheat Distant Hybridization Research Team the National Science Conference Award in 1978.
"Xiaoyan 6 seems like a particularly beautiful child born into the world," Chen Shuyang recalled half a century later. The spikes of this material were neatly elongated, with many grains of excellent quality, full seeds, and a mature, bright yellow color. When the spikes matured, the leaves still retained their green color, continuing photosynthesis to produce carbohydrates, transporting them to the seeds to make them plump.
Chen Shi remembers that Li Zhen brought back a robust "Xiao Yan 6" plant from the community. A meticulous female comrade carefully peeled off the husks, used tweezers to extract each grain of wheat, and then repositioned the husks to obtain a complete "Xiao Yan 6" plant specimen. Everyone who visited the laboratory couldn't help but admire this specimen.
The specimen of wheat distant hybrid variety "Xiaoyan 6" displayed at the National Museum of China.
With the seeds in hand, the next step was the equally busy process of accelerated breeding and regional trials.
Through the tireless efforts of the research team, "Xiaoyan 6" achieved outstanding results in the 1979 Shaanxi Guanzhong wheat variety regional trials, with yield increases observed at 35 out of 37 trial sites, surpassing the control variety by more than 30%.
In 1981, the excellent performance led to the approval of "Xiaoyan 6" by the Shaanxi Provincial Crop Variety Approval Committee. Thus, after 25 years of arduous wheat distant hybrid breeding research led by Li Zhensheng's team, a tremendous success was finally achieved.
From the approval of the variety in 1981 to the receipt of the first prize of the National Science and Technology Invention Award in 1985, within just 5 years, "Xiaoyan 6" had been promoted on 24 million mu of land, generating an economic benefit of 200 million yuan. Its rapid transformation and remarkable economic benefits were remarkable.
In order to cultivate, breed, and promote this "beautiful child" - "Xiaoyan 6", the scientists who developed it neglected their own children.
At that time, Li Zhensheng and his wife Li Jiyun were each leading different research projects, often traveling, staying at field sites, or conducting experiments. Their daughter, Li Bin, had been left unattended since she was six or seven years old, wearing a key around her neck to get food at the canteen and living alone.
Chen Zhaoyang's husband often went on business trips, so she conducted research while taking care of her daughter. Once, she returned home late from field experiments, and her daughter couldn't find her after school. She ran alone from the Northwest Institute of Botany towards the official village experimental field. She was only brought back by her colleagues halfway there.
Mu Sumei and Zhong Guanchang sent their eldest son back to their hometown in Hebei when he was less than a year old, and entrusted their younger son to nearby farmers when he was only 28 days old.
It was their sacrifices and perseverance that earned the highest praise from Shaanxi farmers: "If you want to eat noodles, plant Xiaoyan!"
In more than 20 years of research, Li Zhensheng's team successively developed a series of high-yielding, disease-resistant, and high-quality new varieties such as Xiaoyan Wheat Octaploid, Alien Addition Lines, Alien Substitution Lines, Translocation Lines, and "Xiaoyan" 4, 5, 6, 54, and 81, which were quickly promoted.
Among them, "Xiaoyan 6" has always been the most beautiful "child". It can resist infection by 8 physiological races of stripe rust simultaneously, with high yield and good quality, making white steamed buns and chewy noodles. These qualities made it planted continuously for more than 16 years as the backbone wheat variety in Shaanxi Province, becoming the longest-promoted self-bred wheat variety in China. This also made it an important parent of Chinese wheat breeding, with over 80 derived varieties. By 2003, more than 300 million mu had been promoted nationwide, increasing wheat production by over 15 billion kilograms, temporarily surpassing rice in yield increase speed.
In the breeding community, it is often said that there are no evergreen seeds. In the over 40 years since the approval of "Xiaoyan 6", as technology has advanced, the pace of intergenerational turnover of seeds, as the "chips" of agricultural development, has also accelerated, witnessing the birth and end of a succession of new seeds on the Guanzhong Plain.
But even now, "Xiaoyan 6" is still being sown in Shaanxi, and it still plays an important foundational role in breeding new varieties.
Chen Zhaoyang believes that a research institute must have its own characteristics in order not to be eliminated in competition of its kind, and also to better serve the country's needs. The success of wheat distant hybridization is precisely because this point was firmly grasped.
She said that as an exploratory basic research project, the wheat distant hybridization research team was prepared for a "protracted war" from the beginning, which enabled the team to face difficulties and twists and turns with a firm belief in victory.
Li Zhensheng repeatedly emphasized, "Without collective effort, success is impossible."
After "Xiaoyan 6" won the first prize of the National Science and Technology Invention Award, the prize money was 30,000 yuan, while everyone's monthly salary was less than 100 yuan at the time. Li Zhensheng arranged for each of the 10 members of the research team to receive 1,000 yuan, including himself. The remaining amount was distributed to the driver, the canteen chef, the county seed company, and other people who had helped the research team, each receiving the same amount.
A photo of the award certificate from 1985. Image provided by the Institute of Genetics and Development.
Certainly, the rest of the team always believed that another key to the success of this research was having an outstanding and relatively stable academic leader. Over the past two decades, team members have changed frequently, and Li Zhensheng's administrative roles have also evolved, but what hasn't changed is his role as the head of the distant hybridization research group, which has kept the team's rigorous academic style and good research order intact.
A scientific and enterprising team atmosphere has driven the research group to persist in breakthroughs and continuous innovation.
In the 1960s, distant hybridization could only be carried out at the individual level. By the 1970s, research had progressed to the cellular level, marking a significant leap. Starting in 1978, a new system for breeding blue granule wheat and chromosome engineering was established, shortening the distant hybridization breeding process from decades to 3 years, paving a new path for technology practicality. In 1986, the first International Symposium on Plant Chromosome Engineering was held in Xi'an, further expanding the influence of Chinese wheat genetic breeding internationally.
Today, it's been 68 years since Li Zhensheng and his colleagues boarded that westbound train. The youthful faces of yesteryears are now lined with wrinkles, some have passed away, but the wheat fields stretching across the Guanzhong Plain - the yellow earth they once fought for - still bear the imprint of their youthful memories.
In 1987, some researchers from the Genetic Room of the Northwest Institute of Botany (Li Zhensheng is the first on the left).
Young researcher Li Zhensheng is conducting research on wheat distant hybridization breeding.
Due to his success in distant hybridization of wheat, the elegant Jiangsu lady Chen Shaoyang spent most of her life on the vast northwest land of her motherland. Even in her old age, she still remembers the immense joy brought by the successful cultivation of "Xiaoyan No. 6". One summer day in 1979, she woke up early and briskly made her way from Yangling to Guancun, involuntarily singing softly along the way. When the song reached her ears, she, who had restrained herself for half a lifetime, was startled by her own "exuberance".
Shandong youth Li Zhensheng has been cultivating the loess soil for thirty-one years. Because of the distant hybrid wheat that provided farmers with enough food, he is affectionately known as the "Father of Chinese Distant Hybrid Wheat", alongside Yuan Longping, the "Father of Hybrid Rice", collectively known as "North Li and South Yuan".
On the loess soil, Li Zhensheng always gets along well with the farmers. People from Shaanxi like to eat noodles, often accompanied by a basin of noodles, a small plate of vinegar, a small plate of chili powder, and a small plate of coarse salt. Li Zhensheng is very accustomed to this kind of meal and once told his apprentice, Mu Sumei, who was new to the area: "Put a few grains of salt, add some vinegar, add some chili, mix it up, and it'll taste good."
After the success of wheat distant hybridization, the Shaanxi Provincial Academy of Sciences provided Li Zhensheng with a house in Xi'an, but he chose not to live there, feeling that doing research in Yangling was an excellent choice.
"The mainstream of scientific research should come from production and return to production," Li Zhensheng said. During his years in Yangling, he ate meals at over 120 farmers' homes, knowing what farmers think and need.
"Teacher Li seldom thinks about himself. He has been concerned about the country all his life, always thinking about ensuring that everyone has enough to eat and a good life," Mu Sumei said. "He always encourages us to make contributions."
Encouraged by Li Zhensheng, Mu Sumei and her husband, Zhong Guanchang, were transferred to the Agricultural Modernization Research Institute of the Chinese Academy of Sciences in Shijiazhuang (now the Agricultural Resources Research Center of the Institute of Genetics and Developmental Biology) in 1989 to embark on a "second entrepreneurship." After more than ten years of hard work, they cultivated a group of agricultural research talents and bred China's first high-quality wheat variety for export, "Gao You 503", winning the second prize of the National Science and Technology Progress Award.
In 1987, Li Zhensheng bid farewell to Yangling and returned to the Chinese Academy of Sciences. He transitioned from being a hands-on farmer in the fields to a strategist planning China's wheat fields, proposing a deeply influential suggestion — the management of medium and low-yield fields in the Huang-Huai-Hai region. This project, implemented over six years, increased China's grain production by 50.48 billion kilograms.
He is also the "whistleblower" for China's food security strategy. When China's grain output fluctuated, he timely sounded the alarm and proposed measures to increase production. In response to international questions about "who will feed China," he boldly proposed the idea of "Chinese people feeding themselves."
These scientific research innovations and strategic implementations concerning national food security led to Li Zhensheng being elected as an academician of the Chinese Academy of Sciences in 1991 and receiving the highest national scientific and technological award in 2006.
But he didn't stop there. In 2013, at the age of 82, Li Zhensheng organized and implemented the "Bohai Granary Science and Technology Demonstration Project," achieving an increase of over 20 billion kilograms of grain in the Bohai Sea region over five years. In 2020, nearing the age of 90, Li Zhensheng once again proposed the idea of building a "coastal grass belt" to ensure China's feed grain security. "New China has given me food to eat and the opportunity to go to university, something I never dared to dream of in the past," Li Zhensheng said. "The country has nurtured me, and I should repay the country."
This simple sentiment supports Li Zhensheng in repaying his country with his knowledge and inspires generations of scientists at the Chinese Academy of Sciences.
Today, the Institute of Genetics and Developmental Biology has established the Li Zhensheng "Coastal Grass Belt" Youth Strike Team, concentrating the scientific research strengths of more than ten breeding and farming teams within the institute to tackle challenges in the Yellow River Delta in Dongying. These young scientists of the new era inherit the spirit of the older generation of scientists and continue to write their own scientific papers on the land of their motherland.
Image Source: Visual China
China Science Report (April 18, 2024, 4th Edition, Special Feature)
