obituary Longping (1930–2021) When Mr Yuan Longping passed away on 22 May 2021 at the age of 91, in , Province, , the feld of agricultural science lost a true giant. Mr Yuan was one of the greatest agricultural scientists of our time, and a hero who will be forever remembered in China and around the world. He devoted his entire life to the research of and made great contributions to global food security and poverty alleviation.

uan Longping was born in and challenging, Mr Yuan and his team in 1930 and received his agronomic remained confident. This confidence Ydegree from Southwest Agricultural emerged from the clear research direction College (now ) in and their expertise on male-sterile 1953. Subsequently, he began his teaching phenotyping. Chance favours the prepared career at Anjiang Agricultural School in mind, and when encountering WA, they Hunan Province, China. In the face of severe recognized the treasure at a glance. at that time, he was determined to After establishing the sterile line and the use agricultural science and technology maintainer line, the next step was to find to defeat the threat of hunger. As rice was a suitable restorer line, the last tie of the a staple crop and had great potential for three-line matching to realize the utilization yield improvement, he began to study rice of heterosis. In 1973, Mr Yuan joined the breeding to solve the problem of Hybrid Rice Research Collaborative Group food shortages in China and many of the Hunan Academy of Agricultural developing countries. Sciences and accelerated the progress of In 1961, Yuan Longping unexpectedly developing the three-line matching method. found an ‘outstanding’ rice plant with He found a suitable restorer line that closed excellent characteristics (large panicles the loop and led to breeding of the hybrid and full grains). He carefully collected the rice ‘Nanyou 2’. By successfully developing seeds of this plant and planted more than the first hybrid rice varieties, Mr Yuan 1,000 seeds the following year. Surprisingly, made tremendous contributions to the the traits of the offspring were segregated, in agriculture, and he is and the elite phenotype was lost. Yuan Credit: Lu Boan / Xinhua / Alamy Live News recognized as the ‘father of hybrid rice’ was curious about the reason underlying in China. the huge difference between the offspring The advent of high-yield hybrid rice and the parents. After careful analysis, he male-sterile parent. Mr Yuan’s discovery of greatly alleviated China’s food problems, suggested that this ‘outstanding’ rice was a natural hybrid rice inspired him to search increasing the yield of conventional rice natural hybrid rice — therefore proposing for natural male-sterile rice with stamens by about 20%. After making significant that rice could be hybridized — which that did not develop normally and pistils progress in the 1970s, Mr Yuan generously cast doubts on the popular authoritative that could accept foreign pollen to reproduce shared the results of the three-line method theory that self-pollinated plants, such as hybridized offspring. The male-sterile plant, with domestic and international agronomists rice, had no heterosis and were not suitable if it were to be found, would ideally be the for no profit. In 1980, he volunteered to for hybridization. This interesting finding female parent, which could then be crossed donate key rice varieties to the international fuelled his enthusiasm in the study with other varieties to breed hybrid rice. community, and later trained farmers in of hybrid rice, and thus determined his main With this in mind, Mr Yuan began to look Africa, Southeast Asia and South Asia to research direction. Mr Yuan first proposed for natural male-sterile rice plants. The grow hybrid rice. The hybrid rice technology ‘the three-line matching method’ in the search started in cultivated rice, where six has been introduced and promoted in more paper ‘Male sterility in rice’ published in male-sterile plants were found, but their than 40 countries around the world, and the 1966, laying the scientific foundation for male-sterile traits could not be maintained cultivated area outside China has reached breeding hybrid rice1. ‘Three-line’ refers to in the offspring. Mr Yuan and his team 9 million hectares. three lines of hybrid rice: male-sterile line, then expanded their search to wild rice and After developing the three-line breeding male-sterile maintainer line and male-sterile tried to perform distant hybridization. In method, Mr Yuan continued to seek restorer line. 1970, they finally discovered a male-sterile breakthroughs to simplify the process of Because rice is a self-pollinating plant, wild rice plant called ‘wild abortive’ (WA). seed production. In the 1980s, Mr Yuan it is extremely difficult to remove stamens In 1973, the team harvested WA offspring proposed to improve the hybrid rice manually for the production of hybrid seeds which comprised tens of thousands of breeding strategy from the three-line hybrid in large quantities. Moreover, heterosis male-sterile rice plants — a milestone in rice strain to a two-line variety, and finally is only obvious in the first generation of the development of hybrid rice. WA has to a one-line variety2. The two-line method hybrids, which must be prepared for every contributed ~95% of the male sterility uses temperature-sensitive or photosensitive planting cycle. This becomes the bottleneck source in the entire collection of hybrid sterile materials as the sterile line, omitting in developing hybrid rice for agriculture, rice developed worldwide so far. Although the propagation process of the maintainer with the key solution being to breed with a the process of discovering WA was long line, whilst the one-line method refers to a

858 Nature Plants | VOL 7 | July 2021 | 858–859 | www.nature.com/natureplants obituary breeding technique that uses apomixis to fix associate of the National development and application of high-yield the heterosis, and does not require annual Academy of Sciences in 2006. Mr Yuan has hybrid rice, and important contributions seed production. This method could greatly won numerous titles and awards throughout were also made by many other talented rice reduce the cost of seed production and could his life, but these were not his pursuits. researchers. Mr Yuan’s legacy is not only maximize the application of heterosis. While In a 2019 interview with China Central the progress of hybrid rice — his curiosity, the two-line method has been successfully Television, he said that he had two dreams: devotion, courage, perseverance, diligence, developed and applied, the one-line method one was “for super rice to grow taller than cooperation and selflessness have left an is not yet available. Mr Yuan’s work had to sorghum, with stems each ear as long as a indelible spiritual wealth to us all. ❐ stop here, but the search for the one-line broom, and each grain as big as a peanut”, so method continues. he could “enjoy the cool underneath the rice Kejian Wang ✉ Mr Yuan Longping was credited with crops”; the other was for “hybrid rice [to] be State Key Laboratory of Rice Biology, China National a long list of awards and prizes, including grown all over the world.” For decades, Mr Rice Research Institute, Chinese Academy of China’s first special invention award in 1981, Yuan and countless researchers worked hard Agricultural Sciences, Hangzhou, China. the UNESCO Prize for Science in 1987, to realize these dreams. It is sad that Mr ✉e-mail: [email protected] the Nikkei Asia Award in 1996, the State Yuan has left us, but his dreams are carried Preeminent Science and Technology Award by many plant and agricultural researchers. Published online: 2 July 2021 in 2000, the Wolf Prize in Agriculture and Mr Yuan Longping generated high-yield https://doi.org/10.1038/s41477-021-00962-6 the Word Food Prize in 2004. He was elected hybrid rice by proposing plant genetic References as a member of the Chinese Academy of theories and achieving practical field 1. Longping, Y. Chin. Sci. Bull. 17, 185–188 (1966). Engineering in 1995, and as the foreign production. His breakthrough boosted the 2. Longping, Y. Hybrid Rice 1, 1–3 (1987).

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