[Editor's Note] With funding from the Shanghai Municipal Science and Technology Commission (Project No: 22DZ2304300), The Paper has partnered with World Science to provide popular science coverage of achievements that have received national and Shanghai municipal science and technology awards.
This article focuses on the project that won the First-Class National Science and Technology Progress Award in 2020 for “Creation, Protection, and Utilization of Rice Genetic Resources.” This project was led by Luo Lijun, a researcher and chief scientist at the Shanghai Agricultural Biological Gene Center.
Comparison tests between water-saving drought-resistant rice and traditional rice
Can growing rice also save energy and reduce emissions?
Luo Lijun looks like a farmer. He wears a straw hat, often works in the fields, and has a sunburnt face. As an agricultural scientist and rice breeding expert deeply rooted in the land, his research results blossom on this cherished soil.
He states that breeding is an art, which is why he is inseparable from the land. "If the variety is not good, people will scold you."
Rice is one of the most important food crops in China. In recent years, the water consumption during rice cultivation has been significant, and the use of fertilizers and pesticides has increased. Currently, 70% of the existing arable land in China consists of low- to medium-yield fields. Luo Lijun has set his sights on these underperforming fields. He leads a team to cultivate water-saving drought-resistant rice, which can yield as much as 600 kilograms even when grown in dry land. Currently, over 5 million acres are being cultivated annually.
His goal now is to add 10 million acres of rice cultivation nationwide, increase rice production by 50 billion kilograms, reduce 20 billion tons of water used in rice production, and cut carbon emissions by 20 billion kilograms.
On November 3, 2021, Luo Lijun and his team were awarded the First-Class National Science and Technology Progress Award for their work. This marked the first time research results from Shanghai's agricultural sector received this honor.
The awarded project has also developed 32 new rice varieties tailored to the ecological conditions of African and Asian countries and has had a significant international impact, contributing to the Belt and Road Initiative.
Should rice also focus on “water-saving + energy reduction”?
Wild rice has been distributed in the Yangtze River Delta region for 100,000 years, providing the conditions for early humans to utilize and domesticate rice. About 11,000 years ago, rice was successfully domesticated, marking the beginning of rice farming.
This discovery was reported on May 24 in a paper published in the international journal Science by researchers from the Institute of Geology and Geophysics of the Chinese Academy of Sciences and other institutions.
Even today, researchers continue to develop new rice varieties.
"Generally speaking, it takes one ton of freshwater to produce one kilogram of rice." says Luo Lijun, emphasizing that this method is unsustainable. China is among the 13 countries facing severe water shortages globally.
Luo Lijun noted that out of 450 million acres of rice fields in China, 180 million acres face water scarcity. In the northern regions, groundwater is being over-extracted, while the southern regions frequently experience droughts. Additionally, outside the 450 million acres of rice paddies, there are vast tracts of saline and alkaline land as well as wetlands available for utilization.
Luo decided to tackle the challenge in the 180 million acres of water-scarce rice fields, aiming to achieve high and stable yields on at least 50 million acres under drought conditions.
"China's super rice breeding has addressed high-yield rice fields, but the issues with low- and medium-yield fields still need to be resolved and are relatively challenging. We also need to consider water conservation." This is the “big picture” that Luo Lijun has calculated.
"I have always believed that the development direction of rice (breeding) should focus on resource conservation and environmental friendliness from a national perspective, and enhancing the value of farmland and increasing farmers' income from the perspective of farmers," Luo Lijun explains.
The water-saving drought-resistant rice he and his team cultivated can be grown in waterlogged fields as well as dry land like wheat.
Gene Resource Bank
A source of innovation: Is there a future in agricultural research in Shanghai?
Food is of utmost importance to people. Agriculture is closely related to food security.
“(However) agriculture is not taken seriously." Luo Lijun candidly shares. "A cup of Starbucks costs dozens of yuan, while a pound of rice only sells for two yuan." "The day when everyone stops competing to attend Tsinghua or Peking University, and instead competes to enter agricultural colleges, will be the day agriculture gains respect."
In the metropolis of Shanghai, Luo Lijun emphasizes that he aims not just to farm in Shanghai but across the whole country. "How large is Shanghai’s area? We should be a hub of original innovation." "Agricultural research in Shanghai should produce scientific and technological advancements and high-quality varieties, not just food."
"I am very grateful to the Shanghai Municipal Science and Technology Commission. During my most difficult times, I received foundational research funding from the Commission," Luo Lijun reveals.
In 2003, Luo Lijun's team developed the world’s first drought-resistant sterile rice line, "Hu Huan 1A", and cultivated the first water-saving drought-resistant rice variety in southern China, gradually achieving breakthroughs with hybrid rice. Luo Lijun is thus known as the "agricultural gene expert who continually digs for gold from the treasure trove of rice genetic resources."
After over a decade of effort, Luo Lijun's team has successfully bred water-saving drought-resistant rice varieties across four series including indica, japonica, hybrid, and conventional, which are now being widely applied in production.
Today, the water-saving drought-resistant rice varieties developed by Luo Lijun’s team can yield 1.36 to 1.4 kilograms of rice per ton of water, improving water resource efficiency by over 30%.
Without compromising yield or rice quality, the water-saving drought-resistant rice can reduce irrigation water by 53.3% and fertilizer application by 47.7%, significantly lowering agricultural nonpoint source pollution. Specifically, total nitrogen and phosphorus emissions can be reduced by 69.0% and 36.6%, respectively, with pesticide use slashed by over 80%, and a substantial decrease in carbon emissions, thereby achieving the green agricultural production goals of "resource conservation, environmental friendliness, farmland valuation, and farmers’ income increase."
Writing research papers on the land: Breeding is an art
Have you ever seen rice growing on a mountain?
As early as 1988, Luo Lijun conducted a survey of rice resources in Guangxi, where he first encountered traditional dryland rice.
Local villagers clear mountain slopes by burning and then directly scatter or drill seeds. By mid to late October, they start harvesting in the mountains.
Although the yields are low, looking at the vast fields of dryland rice, Luo Lijun was struck by its tenacity. He realized that if the strengths of dryland rice could be integrated to cultivate new varieties, it could open new avenues for rice planting.
Luo and his team discovered that the reason dryland rice often has low yields is that the yield genes and drought resistance genes are linked and have opposing effects.
He developed the first new variety of dryland rice that balances drought resistance and high yield—water-saving drought-resistant rice. By integrating drought-resistant traits from dryland rice with high-yield and quality traits from paddy rice, Luo’s team has created various series of water-saving drought-resistant rice, including hybrids and conventional varieties.
Water-saving drought-resistant rice is just one of Luo Lijun's many research achievements.
He told The Paper that the project that won the First-Class National Science and Technology Progress Award in 2020 encompasses three aspects: first, a platform for the protection and utilization of rice germplasm resources; second, "the exploration of the entire gene is a theoretical innovation"; and third, the breeding and large-scale promotion of a significant number of excellent varieties.
"Breeding is a combination of science and art," he says. "Currently, while we have not fully clarified the mechanisms of drought resistance, conventional breeding methods are the most effective. Conversely, once we alter disease and pest resistance traits based on this foundation, modern biotechnology becomes effective."
In simpler terms, breeding involves using certain methods to cultivate and select a superior variety, which is then promoted. Selecting varieties is essentially selecting gene combinations. A good variety fundamentally possesses "excellence" at the genetic level, supplemented by good field management, resulting in a successful harvest. The work of breeders involves figuring out how to pair good genes together, creating combinations, and selecting them. The methods for pairing genes, including hybridization or gene editing and modification, ultimately lead to genetic changes that manifest in the traits of the variety.
What is a gene?
The genetic information of plants and animals is primarily stored in long chains of DNA (deoxyribonucleic acid). A gene can be considered as segments of DNA, representing the smallest unit of hereditary material that determines the excellent traits of crops. Breeding, therefore, involves screening different genes and then combining them.
From wild rice to domesticated rice, over thousands of years of domestication has created a treasure trove of rice genetic resources.
To refine this “art”, Luo Lijun has led his team to establish the world's largest functional gene resource bank for rice. Over the past 20 years, they have gathered, preserved, and assessed rice germplasm resources worldwide, setting up a domestic-leading and internationally advanced system comprising “one bank and three systems” for the protection and use of these resources, achieving comprehensive, traceable management of germplasm resources. They collected over 230,000 germplasm resources from a total of 93 families, 360 species in Shanghai, selecting the most suitable germplasm resources for cultivation that can improve yield across various traits, including tall and short stalks, glutinous and non-glutinous types, and lodging resistance versus susceptibility.
Luo Lijun is dedicated to exploring genes that confer high yield, quality, drought resistance, disease resistance, and pest resistance, using these bases for innovation: studying drought resistance mechanisms to further improve relevant varieties’ drought resilience; achieving yields as high as super rice; enhancing cultivation techniques throughout the growth process to improve resistance to diseases and pests; and refining rice quality to suit the preferences of different regions.
"The final step must be in the field," Luo Lijun emphasizes. "In the lab, it looks great, but that's entirely different from actual field conditions." "If the variety is poor, people will complain."
Luo and his team have also set a "1522" development goal: to add 10 million acres of rice cultivation nationwide, increase production by 50 billion kilograms, reduce 20 billion tons of water used in rice production, and decrease carbon emissions by 20 billion kilograms of CO2 equivalent.
On the wall of his office hangs a piece of calligraphy: “Natural Abundant Rice.” Luo Lijun speaks softly yet firmly as he leads his team forward bravely across golden rice fields.