A supplement to the "Timeline of Hybrid Rice Technology Development":

1865: Mendel publishes the laws of heredity.
Result: Lays the foundation for modern genetics, proving that biological traits can be inherited and combined.
1900: The European scientific community rediscovers Mendel's laws of heredity.
Result: Modern genetics is formally established.
1908: American scientist George H. Shull proposes the theory of heterosis (hybrid vigor).
Result: It is discovered that the first generation (F1) of a cross between different varieties can exhibit growth and yield advantages far beyond the parent lines.
1920s–1930s: Large-scale commercialization of hybrid corn in the United States.
Result: First demonstration that "hybrid breeding" can become a modern agricultural industrial system.
1950s: Japan, the United States, and other countries begin research on male sterility in rice.
Result: The discovery that male sterility can solve the difficulty of artificial hybridization in rice, laying the theoretical foundation for future hybrid rice.
1964: Yuan Longping begins systematic research on rice heterosis.
Result: Proposes the research direction that "rice can also utilize heterosis."
1970: Yuan Longping's team discovers the "wild abortive" (WA) male sterile wild rice material.
Result: Finds the most critical genetic resource for achieving industrialization of hybrid rice.
1973: Yuan Longping's team completes the "three-line method" hybrid rice technical system.
Technology: Male sterile line (A) + maintainer line (B) + restorer line (R).
Result: First large-scale seed production and industrial cultivation of hybrid rice.
1976: China begins nationwide promotion of three-line hybrid rice.
Result: China's grain output increases significantly, and hybrid rice becomes an important foundation for national food security.
1980s: China's hybrid rice technology begins to be exported globally.
Result: Many countries in Asia, Africa, and Latin America begin to introduce hybrid rice technology.
1986: Yuan Longping proposes the development path of "three-line → two-line → one-line."
Result: Promotes hybrid rice toward higher efficiency and lower cost.
1990s: Chinese scientists develop the "two-line method" hybrid rice.
Technology: Utilizes photo-thermo-sensitive genic male sterile lines, eliminating the need for a maintainer line.
Result: Improves breeding efficiency and reduces seed production complexity.
1996: China launches the "Super Hybrid Rice Program."
Result: Continuously breaks records for rice yield per mu.
2000s: Molecular marker-assisted breeding technology enters hybrid rice research.
Result: Breeding moves from the era of experience to the molecular era.
2010s: Genome-wide selection, gene editing, and other technologies enter the field of rice breeding.
Result: Hybrid rice enters the era of precision breeding.
Summary:
• Heterosis theory: Mainly from the European and American genetics system.
• Basic research on rice male sterility: Japan and other countries made significant contributions.
• Three-line method industrialization system for rice: First completed by Yuan Longping's team.
• Two-line method and super hybrid rice: Mainly further developed by China's research system.
Therefore, it is inaccurate to say that "hybrid rice was entirely invented by Yuan Longping"; it is also inaccurate to say that "Yuan Longping merely copied Japanese technology."
A more accurate statement is: Based on global genetics and rice breeding research, Yuan Longping's team was the first to achieve large-scale engineering and industrial application of hybrid rice, which is the core of his historical contribution.