China creates world’s first clone-hybrid rice that could double global output

Chinese researchers have developed a revolutionary form of hybrid rice that can replicate itself through seeds that are clones, faithfully preserving high-yield traits generation after generation.\nThe team says its breakthrough could transform global agriculture by dismantling the biggest barrier to hybrid rice production: the need for farmers to buy expensive new hybrid seeds every season.\nAs hundreds of millions of people around the world face acute food insecurity, hybrid rice has promised dramatically higher yields: nearly four times more in parts of Africa compared to traditional varieties.\n\n\nIf all rice farmers could plant the new hybrid variant, the world’s rice production could double, according to some industry estimates.\nHowever, the price of hybrid seeds can reach 200 yuan (US$28) per kilogram in China, and even higher in other countries – up to 100 times more than that of regular rice seeds.\nMoreover, the offspring of these high-priced seeds lose their hybrid vigour – superior traits from crossbreeding – forcing farmers to buy seeds again every year.\nA research team led by Wang Kejian at the Chinese Academy of Agricultural Sciences’ China National Rice Research Institute has developed hybrid rice capable of near-perfect clonal reproduction through apomixis – a process in which seeds develop without fertilisation.\nThe team’s work, which is pending peer review, was published on the preprint server bioRxiv on October 17 under the title “Fixing Hybrid Rice: >99% Efficient Apomixis with Near-Normal Seed Set.”\nIts new Fix8 series achieves more than 99.7 per cent cloning efficiency with seed-setting rates rivalling conventional hybrids, effectively creating self-replicating super rice.\nThis “one-line” system slashes seed production costs by up to 99 per cent, potentially cutting prices from hundreds of yuan per kilogram to just a few yuan, which is comparable to the price of regular rice.\n“This was the first introduction of the apomixis trait into hybrid rice, a breakthrough from ‘0 to 1’,” Wang told China Science Daily on December 27.\n“Once commercialised, the cost of hybrid rice seeds could drop from the current 20 to 100 yuan per jin (500 grams) to the level of conventional rice at 2 to 5 yuan per jin, directly benefiting farmers.”\nChina pioneered hybrid rice, bred from two genetically distinct parents to achieve significantly higher yields. It created the first high-yield commercial strains and remains the world’s largest producer and consumer of hybrid rice.\nHowever, hybrid rice is more expensive for farmers as they must buy new seeds after each harvest, unlike inbred rice varieties which can be saved and replanted.\nWang, who is chief scientist of the rice chromosome engineering and genome editing team, has long focused on apomixis in hybrid rice.\nIn agricultural science, apomixis is hailed as a “holy grail”. This method of clonal reproduction through seeds allows the superior traits of a hybrid to be fixed and passed down indefinitely.\nIn 2017, Wang’s team used gene editing to knock out four genes involved in rice reproduction, enabling hybrid rice to bypass the meiosis cell division process and fertilisation. In January 2019, these findings were published as a cover article in Nature Biotechnology, announcing the first successful creation of clonal hybrid rice seeds.\nThat achievement attracted widespread attention. The late Yuan Longping, revered as the “father of hybrid rice”, congratulated the team, stating that the work showed “the feasibility of apomixis in hybrid rice, marking a significant breakthrough … I hope to see continued efforts and the early application of one-line hybrid rice in production”.\nWang told China Science Daily: “However, that early strategy still faced issues, like low seed-setting and induction rates”.\nIn their latest bioRxiv preprint, Wang’s team reports that it had thoroughly addressed the issues. They identified and named a key rice gene Huaxu, inspired by the Chinese myth symbolising “birth without father”.\nThey transferred this gene into rice ovules, enabling embryo development without fertilisation. Combined with a “clonal gamete” technique, this system achieves nearly 100 per cent clonal seed production.\nThe resulting rice lines, the Fix8 series, achieved seed-setting rates between 50 per cent and 74 per cent. Fix8#3 reached 74.3 per cent, comparable to conventional hybrid rice (74.9 per cent), solving the issue of “high cloning efficiency but low yield”.\n\n\nThe Fix8 seeds have been propagated to the third generation, maintaining a clonal heredity efficiency exceeding 99.7 per cent with no signs of trait degeneration under varying field conditions.\n“We have established an apomixis system with a normal fruit set rate, currently near 80 per cent, which meets commercial standards,” Wang said.\nThese achievements are accelerating application efforts. The team has developed six apomictic rice varieties, or exact clones, tested over multiple generations in Hainan province in southern China and Zhejiang province in the east.\nThe South China Morning Post has sought comment from Wang.\n