During the journey, a fellow traveler was surprised to see one tall, thin youth with glasses carrying a bag full of grass roots. When asked, he simply replied, "The Northwest might need them."
These young scientists were responding to the national call to support the development of Northwest China. 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 Chinese Academy of Sciences and Ministry of Water Resources, hereafter referred to as the Institute). Among them was a young man named Li Zhensheng, carrying those grass roots. Little did he know that after 25 years of painstaking research, those roots would give birth to the first disease-resistant and high-yielding distant hybrid wheat, "Xiaoyan 6," effectively controlling the spread of rust disease and ushering in a new era of distant hybrid wheat breeding in China.
Their mission? To ensure food security for the people.
In the early days of the People's Republic of China, the per capita grain output was only around 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.
At that time, wheat rust disease was rampant in the Yellow River Basin, causing annual wheat losses exceeding tens of billions of kilograms, equivalent to one twentieth of China's total grain output at the time. Premier Zhou Enlai emphasized the need to combat wheat rust disease with the same urgency as combating human diseases.
Wheat rust disease posed a significant threat, with its urediniospores releasing vast amounts of rust-colored spores upon maturity, spreading rapidly across entire fields within days. Once infected, wheat could suffer yield losses of 30% to 50%, or even total crop failure.
What made matters worse was that using conventional breeding methods, it took around 8 years to breed new wheat varieties resistant to the disease through crossbreeding with resistant strains. However, wheat rust disease could adapt to these "close-relative breeding" varieties, rendering them susceptible within an average of only 5 and a half years.
Standing amidst the vast wheat fields of the Guanzhong Plain, Li Zhensheng witnessed the devastating effects of wheat rust disease firsthand. "Walking through the wheat fields in black pants, they would turn yellow. Some farmers cried at the sight."
How to overcome the fatal flaw of breeding speed lagging behind the mutation rate of the disease? Li Zhensheng pondered tirelessly for a solution.
Born in rural Zibo, Shandong Province, Li Zhensheng experienced poverty and famine in his youth. Years of drought left the village stripped of its elm leaves and bark, with even onion roots and garlic skins being consumed as food. This experience instilled in him a deep appreciation for the value of food.
In his second year of high school, Li Zhensheng dropped out to find work in Jinan to ease the burden on his family. It was the promise of "free board and lodging" in an enrollment notice from Shandong Agricultural College that caught his attention. Succeeding in the entrance exam, he embarked on the path of wheat breeding.
After graduating, Li Zhensheng was assigned to the Institute of Genetics and Selection, Chinese Academy of Sciences. Joining the Academy, he was both surprised and somewhat disappointed: He had hoped to pursue genetic breeding research but was instead assigned to the cultivation group, where he worked with various grasses. Little did he know that this seemingly unrelated work would pave the way for a new field of wheat genetic breeding.
Looking at the grass roots he brought from Beijing, Li Zhensheng conceived a bold idea: Could he breed a disease-resistant wheat variety by crossing grasses with wheat?
"Wheat, after thousands of years of cultivation, is like a flower in a greenhouse, gradually losing its disease resistance genes. On the other hand, wild grasses in nature have been naturally selected, eliminating individuals that are not disease resistant, making them an excellent gene pool." Li Zhensheng thought, if he could transfer the disease resistance of wild grasses to wheat, it would significantly enhance wheat's resistance to disease.
This idea received support from botanist Wen Honghan and plant pathologist Li Zhenqi.
However, wheat has undergone evolution for nearly ten thousand years. Li Zhensheng had no certainty about the likelihood of success or how long it would take to succeed in artificial breeding.
In fact, Chen Shaoyang, a graduate of the Northern Jiangsu Agricultural College, arrived at the Institute before Li Zhensheng. She attempted to transfer the perennial and disease-resistant traits of Bent grass to wheat but after two years of research, there was no change in the wheat's characteristics.
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 brought in the courtyard of the Institute, set up a simple semi-underground soil greenhouse for seed propagation, and quickly formed a young scientists' research group, including members such as Chen Shaoyang, Li Rongling, Liu Guanjun, and others.
Crossbreeding wheat with distantly related grasses presented three major challenges: first, the hybrids were often incompatible, making successful crossbreeding difficult; second, the hybrids were often sterile, like mules produced from horses and donkeys, lacking reproductive 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. They initially selected 12 grass species for hybridization with wheat, of which only three were successful. Among them, the offspring of Elymus elongatus grew the best, so they focused their research on it. Elymus elongatus flowered later than wheat, so they adjusted its flowering period by supplementing light to induce flowering two months earlier, successfully pollinated it; when the hybrid varieties failed to germinate, they squatted in the fields to inspect each wheat plant, identifying hybrids with normal male and female flowers, and repeatedly crossed them with the parental strains; sometimes a hybrid looked promising, but the next generation was completely different, so they reevaluated and selected again and again... Accident and Necessity
After eight years of research, the ideal wheat variety still hadn't emerged.
"Crossing distant species seems to be a bottomless pit of work." "It wastes funds and time."... Criticisms poured in, and the research team found themselves in a predicament.
Fortunately, when Li Zhensheng began researching distant hybridization, he remembered a philosophical discourse he heard from Aiqi when he first arrived at the Chinese Academy of Sciences. He adopted a "two-pronged approach," conducting research on both distant wheat varieties and inter-varietal hybridization, not putting all his eggs in one basket.
This combined approach of distant and near goals proved to be a great help. At the time, some varieties bred through inter-varietal hybridization by the research team were promoted in Shaanxi, allowing the research on distant hybridization to continue.
In the summer of 1964, there was continuous rain just over a month before the wheat ripened. On June 14th, the weather suddenly turned sunny, and over a thousand hybrid offspring of wheat almost all turned "green-dry" in just one day—leaves were still green, but the plants had dried up. Only one plant withstood the intense sunlight, maintaining its golden color.
This hybrid variety that escaped "green-drying" gave Li Zhensheng's research team great confidence. This material, named "Xiaoyan 55-6", was resistant to high temperatures and diseases, becoming the "ancestor" of the later widely promoted "Xiaoyan No. 6".
"In scientific research, there is necessity within accident; it depends on whether you can seize the opportunity." Li Zhensheng spoke of this "accident" and "opportunity" in such a way. At that time, he checked the field every day, so meticulously that he could tell which material was growing where without looking at the record book, ultimately detecting subtle differences.
"Xiaoyan 55-6" was just an initial success, and the road to the practical application of distant hybrid varieties was still long.
In 1965, Li Zhensheng led the research team to the newly established Northwest Institute of Botany, Chinese Academy of Sciences (hereinafter referred to as the Northwest Institute of Botany, later merged into Northwest A&F University). In addition to the institute's seven or eight mu of experimental fields, he also opened up 30 mu of experimental fields in Guancun nearby to conduct research on distant hybrid breeding. Mu Sumei and Zhong Guanchang, graduates of Hebei Agricultural University, were assigned to the institute to conduct research under Li Zhensheng.
Mu Sumei remembered that it was a 10-li dirt road from the Northwest Institute of Botany to Guancun's experimental fields. At that time, the entire research team had only one bicycle. During sowing 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 be difficult to walk on. Rain boots would sink into the mud, with mud accumulating on the shoes, making what would usually be a one-hour journey take nearly two hours.
When farmers sow wheat, they sling a wicker basket over their arms, reach in, grab a handful of seeds, and scatter them in the freshly turned furrows, completing the task. It was different for the research team; they had to plan the planting rows for each material carefully. Scarce materials even had to be sown grain by grain, with each row labeled and a signboard inserted into the ground for each row of material.
Speaking of sowing, Zhou Hanping, a senior experimentalist at Northwest A&F University, recalled that shortly after joining the research team, he experienced Li Zhensheng's "wrath."
Once, it rained continuously for half a month, and to avoid affecting the later stages of the research, everyone sowed in the rain. The field was muddy, and Zhou Hanping's work was a bit rough. Unexpectedly, his carelessness was noticed by Li Zhensheng.
"No matter how heavy the rain is, rules must be followed." Li Zhensheng, who was usually easy-going, said sternly to Zhou Hanping, "Only under very strict conditions can genetic differences be observed." With that, Li Zhensheng demonstrated it himself. This greatly educated Zhou Hanping, who became very meticulous in subsequent experiments.
Not only sowing, but also harvesting wheat, pulling carts, and threshing, all these time-consuming and laborious tasks were done by the research team themselves.
When harvesting wheat, the scorching heat made the leaves lose their moisture, drooping one by one. They braved the heat to pull out the wheat from distant hybridization and placed them on carts to bring back to the Northwest Institute of Botany.
The precious materials couldn't be threshed mechanically, so they squatted on the ground, hands equipped with a small rubbing board. After rubbing the wheat ears back and forth, they let the grains fall into boxes beside them. Then, they used a small fan to blow away the chaff, checked the number, color, and plumpness of the grains, and finally packed them into a small leather bag, labeled with a number.
Time flew by, seasons passed. Houses, warehouses, and a two-story building were gradually built in the experimental fields in Guancun, sparing everyone the daily trip of 20 li to check on the wheat.
In 1970, after six years of repeated hybridization and backcrossing, Li Zhensheng's research team obtained a very good new material, named "Xiaoyan 96"—this was the "father" of "Xiaoyan No. 6". This material possessed excellent characteristics such as disease resistance, early maturity, heat and drought resistance, and high quality. Using it as a parent for hybridization, the first generation of "Xiaoyan No. 6" was finally obtained the following year.
However, the "Xiaoyan No. 6" at that time still had the problem of unstable fertility. It wasn't until 1977 that the research team used laser irradiation on the hybrid seeds and repeatedly bred them to the seventh generation, finally obtaining an excellent individual plant—this was the original plant of "Xiaoyan No. 6" widely planted in the Huang-Huai-Hai region later.
"We took a 'breakthrough' approach to this individual plant, uniformly sowing its seeds in a small area, resulting in consistent population traits." Li Zhensheng said.
Under limited irrigation conditions, this batch of seeds yielded over 350 kilograms per mu, a 17% increase compared to the control variety. These achievements earned the Wheat Distant Hybridization Research Team the National Science Conference Award in 1978.
"A beautiful child"
"'Xiaoyan No. 6' seems like a child born extraordinarily beautiful." Half a century later, Chen Shaoyang still vividly remembers that this material had neat and long ears, abundant and high-quality grains, full seeds, and mature golden brightness; when the ears matured, the leaves still retained their green color, allowing for continued carbohydrate production through photosynthesis, which was transported to the seeds to make them plump
Chen Shuyang remembered that Li Zhensheng selected the healthiest "Xiao Yan 6" plant from the community and brought it back. A meticulous female comrade peeled off the husk, used tweezers to extract each grain of wheat, and then replaced the husk to obtain a complete specimen of "Xiao Yan 6". 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 propagation and regional trials.
Through the unremitting efforts of the research team, "Xiaoyan 6" achieved remarkable results in the 1979 regional wheat variety trials in the Guanzhong region of Shaanxi Province, with yield increases observed at 35 out of 37 test sites, surpassing the control variety by over 30%.
In 1981, the outstanding performance led to the approval of "Xiaoyan 6" by the Shaanxi Crop Variety Approval Committee. Thus, after 25 years of arduous wheat distant hybrid breeding research led by Li Zhensheng, the research team finally achieved tremendous success.
From the variety approval in 1981 to winning the first prize of the National Science and Technology Invention Award in 1985, in just five years, "Xiaoyan 6" had been promoted on 24 million mu of land, generating economic benefits of 200 million yuan. The speed of its achievement transformation and the significant economic benefits were remarkable.
In order to cultivate, propagate, and promote "Xiaoyan 6", the scientists who developed it overlooked their own children.
At that time, Li Zhensheng and his wife, Li Jiyun, each led different projects and often went on business trips, field visits, or experiments. Their daughter, Li Bin, had been left unattended since she was six or seven years old, carrying a key around her neck, eating alone in the cafeteria, and living alone.
Chen Zhaoyang's husband often went on business trips, so she juggled research and 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, and was only brought back by her colleague 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 youngest son to nearby farmers when he was 28 days old, all for the sake of their research.
It was their sacrifice and perseverance that earned the highest praise from Shaanxi farmers: "If you want to eat noodles, plant Xiaoyan!"
In over 20 years of research, Li Zhensheng's research team successively bred 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, and rapidly promoted them.
Among them, "Xiaoyan 6" has always been the most beautiful "child". It can resist infection from 8 physiological races of stem rust simultaneously, with high yield and good quality, making white mantou and chewy noodles. These qualities made it the backbone wheat variety in Shaanxi Province for over 16 years, becoming the longest-promoted self-bred wheat variety in China. This also made it an important backbone parent of wheat breeding in China, with over 80 derived varieties. By 2003, over 300 million mu of land had been promoted nationwide, increasing wheat production by over 15 billion kilograms, temporarily surpassing rice in yield increase rate.
The waves of wheat sing.
Breeding circles often say that there are no perennial seeds. In the over 40 years since the approval of "Xiaoyan 6", with the acceleration of technological development, the intergenerational turnover speed of seeds, as the "chips" of agricultural development, has also increased. The Guanzhong Plain has witnessed the birth and end of one batch of new seeds after another.
But to this day, "Xiaoyan 6" is still being sown in Shaanxi, and it still plays an important role as a cornerstone in breeding new varieties.
Chen Zhaoyang believes that a scientific research institute must have its own characteristics in order not to be eliminated in competition with similar entities, and to better serve the needs of the country. The success of wheat distant hybridization was 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 maintain a firm belief in victory in the face of difficulties and setbacks.
Li Zhensheng repeatedly emphasized, "Without collective efforts, success is impossible."
After "Xiaoyan 6" won the first prize of the National Science and Technology Invention Award, the prize money totaled 30,000 yuan, while the monthly salary at that time was less than 100 yuan for everyone. 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, cafeteria chef, county seed company, and other people who had helped the research team, also giving each of them 1,000 yuan.
Over the past two decades, amidst various changes in personnel and administrative roles, one constant remained at the forefront of the success of the research: an outstanding and relatively stable academic leader. Despite fluctuations in administrative responsibilities, Dr. Li Zhensheng continued to lead the distant hybridization research group. This ensured the maintenance of rigorous academic standards and a sound research environment within the team.
A culture of scientific rigor and progressiveness propelled the research group to persevere in their pursuits and continually innovate.
In the 1960s, distant hybridization was limited to the individual level. By the 1970s, research had progressed to the cellular level, marking a significant advancement. Starting from 1978, the development of the blue-grained wheat and chromosome engineering breeding new system shortened the decades-long process of distant hybridization breeding to just three years, paving the way for practical technological applications. In 1986, the first International Symposium on Plant Chromosome Engineering was held in Xi'an, further amplifying China's influence in wheat genetic breeding internationally.
Today, it has been 68 years since Dr. Li Zhensheng and his colleagues embarked on that westward journey. The youthful faces of yesteryears are now adorned with wrinkles, and some have passed away. Yet, across the wheat fields stretching to the horizon in the Guanzhong Plain—the same land they once fought for—remains etched with memories of their youth.
In 1987, some researchers from the Genetic Division of the Northwest Institute of Botany (with Li Zhensheng on the left).
Young Li Zhensheng is conducting research on distant hybridization breeding of wheat.
Due to his success in distant hybridization of wheat, the elegant Jiangsu woman, Chen Ziyang, spent most of her life in the northwestern land of her homeland. Even in her old age, she never forgot the immense joy brought by the successful cultivation of "Xiaoyan No. 6" in 1979. One summer day, she woke up early, and with light footsteps, she sang softly on her way from Yangling to Guancun. As her song reached her ears, she, who had restrained herself for half a lifetime, was startled by her own "outburst."
Shandong youth Li Zhensheng has been toiling on the loess land for thirty-one years. Due to the distant hybrid wheat that brought food security to farmers, he is affectionately called the "Father of Chinese Distant Hybrid Wheat," alongside Yuan Longping, the "Father of Hybrid Rice," collectively known as "South Yuan and North Li."
On the loess land, Li Zhensheng always bonded with the farmers. Shaanxi people love noodles, often serving a bowl of noodles, a small dish of vinegar, a small dish of chili powder, and a small dish of coarse salt. Li Zhensheng adapted well to this meal, telling his apprentice Mu Sumei, who was new to the area, "Just add a few grains of salt, a little vinegar, a bit of chili, mix it, and it'll taste good."
After the success of distant hybridization of wheat, the Shaanxi Academy of Sciences provided Li Zhensheng with a house in Xi'an, but he didn't move in, feeling that doing research in Yangling was an excellent choice.
"The mainstream of scientific research should originate from production and return to production," Li Zhensheng said. During his years in Yangling, he had meals in over 120 farmers' homes, understanding what the farmers wanted and needed.
"Teacher Li seldom thinks about himself. He has been worrying about the country all his life, always thinking about ensuring that everyone has enough food to eat and a good life," Mu Sumei said. "He always encourages us to make contributions."
Encouraged by Li Zhensheng, Mu Sumei and the couple Zhong Guanchang were transferred to the Agricultural Modernization Research Institute of the Chinese Academy of Sciences in Shijiazhuang (now the Center for Agricultural Resources Research of the Institute of Genetics and Developmental Biology), for a "second entrepreneurship" in 1989. Through more than ten years of hard work, they nurtured a group of agricultural research talents and bred China's first export-quality wheat variety, "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 cultivator in the fields to a strategist planning China's wheat fields, proposing a profoundly influential project—reclamation of middle 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 production fluctuated, he timely sounded the alarm and proposed measures to increase production. In response to international questions about "who will feed China," he boldly put forward the idea of "Chinese people feed themselves."
These scientific research innovations and strategic implementations concerning national food security led to Li Zhensheng's election as an academician of the Chinese Academy of Sciences in 1991 and his receipt of 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 Technology Demonstration Project," achieving an increase of over 20 billion kilograms of grain production in the Bohai Sea area over five years. In 2020, nearing the age of 90, Li Zhensheng once again proposed the construction of the "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, which 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 motivates Li Zhensheng to repay his homeland 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 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 contribute to scientific papers on the land of their homeland.
Image Source: Visual China
