China’s new hybrid rice could preserve its high-yield characteristics across generations, potentially allowing farmers to re-sow seeds instead of buying new seeds each year.Scientists at China’s National Rice Research Institute in Hangzhou have developed a self-cloning hybrid rice system that maintains superior crop yields while achieving more than 99 percent cloning efficiency. Led by researcher and professor Wang Kejian, the study was published in the academic journal Vita on July 21, with additional details reported by the Global Times.This breakthrough targets a long-standing bottleneck in modern agriculture known as hybrid vigor. Hybrid rice gives 10 to 30 percent higher yields than standard varieties. However, when farmers harvest and replant seeds from traditional two-row or three-row hybrid crops, the genetic traits diverge in the next generation, causing the yield advantage to disappear.
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As a result, growers are forced to purchase fresh hybrid seeds every season.
How HUAXU unlocks gene seed cloning
Wang’s research team began addressing this issue in 2013 by focusing on synthetic apomixis, a natural plant process where seeds are formed without fertilization, creating exact genetic copies of the parent plant.This success depends on an endogenous rice gene called HUAXU. When expressed in hybrid rice egg cells, HUAXU triggers parthenogenesis, causing the egg cell to develop into an embryo without the need for male fertilization. By combining this mechanism with a clonal gamete strategy, the team created modified rice lines known as Fix8.Unlike earlier gene-editing approaches, which required the introduction of foreign genes, HUAXU is a naturally occurring gene within rice. This interoperability simplifies regulatory review and commercial deployment.In large-scale field trials across different rice varieties, across multiple generations and varying weather conditions, the Fix8 lines maintained normal fertility and crop yields as well as cloning efficiency above 99 percent. In theory, obtaining a single hybrid seed would allow a farmer to continuously cultivate high-yield rice without having to purchase new stock each year.The first experiments conducted by the team in 2017 reached only 5 percent cloning efficiency, while rival research groups later achieved about 95 percent using complex gene mutations. Reaching the 99 percent mark meets the threshold required for commercial application, fulfilling a long-sought goal in plant breeding often referred to as the “one-row hybrid rice” concept.
Chinese scientists have made a major breakthrough in hybrid rice breeding with the development of “clonal hybrid rice” (Photo: Courtesy Wang Kejian)
Cut seed expenses to help global farms
High production costs have historically limited the spread of hybrid crops. Hybrid rice currently accounts for about 50 percent of rice fields in China, but covers only 5 percent of global rice acreage.Producing hybrid seeds through traditional cross-breeding is labor-intensive, costing 10 to 20 times more than conventional seeds even before processing, storage, and transportation expenses are taken into account.“Hybrid seeds cost 10 to 20 times more to produce than conventional seeds, making high-yield hybrid rice unattainable for many developing regions, especially African countries, where high yields are needed most,” Wang told the Global Times.New cloning technology reduces those expenses significantly. According to data provided by Wang’s team, seed prices for the Fix8 lines may fall between 2 to 5 yuan per half kilogram. Standard hybrid seeds in China currently sell for 20 to 100 yuan per half kilogram.Increasing global hybrid rice adoption from 5 percent to 25 percent of agricultural land would significantly increase world grain supply. Removing the need for annual seed production gives plant breeders more freedom to introduce genetic diversity, helping crops withstand climate stress, diseases and extreme weather.
Supporting national and global food security
This development has major implications for China’s agricultural policy and global grain markets. China supports about a fifth of the world’s population using less than 9 percent of global arable land, with hybrid rice serving as the primary driver of that agricultural production.Official figures show China’s total grain output has remained stable at more than 700 billion kilograms for two consecutive years. This figure is well above the internationally recognized safety baseline of 400 kg per person.By eliminating the need for annual hybrid seed production, the new one-line system provides a sustainable way to ensure high yields, reducing production costs for farmers while strengthening long-term food self-sufficiency.
Technological advances in seed propagation
Traditional hybrid rice cultivation relies on multi-row breeding systems, mainly three-row and two-row methods. These techniques require special cross-breeding between male sterile lines and restorer lines to obtain viable hybrid seeds. Because this labor-intensive process must be repeated every season, seed purity and quality control remain persistent challenges for commercial growers.The development of synthetic apomixis using HUAXU genes fundamentally changes this dynamic. By inducing parthenogenesis directly within unfertilized egg cells, the plant creates haploid progeny that carry the exact genetic material of the mother plant.Cloning efficiency serves as the primary benchmark for measuring how reliably a crop retains its hybrid vigor. While earlier efforts struggled to maintain high success rates without compromising overall plant fertility, exceeding the 99 percent threshold in field trials confirms that clonal seeds can be multiplied over multiple generations without losing productivity or crop resilience.