Fifty years of hybrid rice research in China

Abstract

It has been over a half century on the hybrid rice research in China since the first time discovery of male sterile rice by Yuan LongPing in the indica cultivar Dong-Ting-Zao-Xian in 1964. In the last 50 years, hybrid rice contributes substantially on the security for food supply in China, and which makes China take a leading role on hybrid rice around the world. Here, in this context, the trajectory of hybrid rice development in China was reviewed, and strategies for the production and development of hybrid rice in the industrilization era were discussed. In the 1970, the discovery of natural male sterile line named “Wild Abortive” by Li Bihu, assistant of Yuan LongPing, in wild rice Oryza rufipogon in Sanya, Hainan Island, marked a great breakthrough to the hybrid rice development. Two years latter, the first commercial cytoplasmic male sterile line Zhenshan 97A was developed by consecutive backcross of Zhenshan 97 as male parent to the “Wild Abortive” male sterile line, which established a foundation for the three-line hybrid rice. In 1976, the hybrid rice combinations were released for commercial production after a series of elite fertility restorer lines including IR6 and IR64 etc. being discovered. The successful breeding of WA-type hybrid rice inspired people to create new CMS by wide crossing, then, a great many of CMS types including Honglian, Dian I/II, Gang and D-types, and their corresponding restorer lines were developed from a variety of wild rice or landraces by different research groups in 1970s–1980s. These researches greatly enriched the diversity of hybrid rice. As the development of three line hybrid rice, a new genic male sterile line which showed reversible transition between male sterility and fertility under different temperature and photoperiod environments was discovered by Shi MingSong in 1973. This discovery brought the dream to breed two-line hybrid rice into truth in 1990s after tremendous efforts. In order to resolve the problems for hybrid rice development in breeding practice, some questions such as ideal plant architecture, heterosis and combining ability, CMS and fertility restoring genes etc. were raised. These questions drive us to deepen understanding the essentiality of heterosis and rice yield, and lead to a trend that a great many agronomic important genes were cloned in the last two decades, which greatly promotes the application of molecular technologies in hybrid rice development. After half-a-century development, hybrid rice has been spread over forty countries in Southeastern Asia, Africa and Southern American apart from China. It also has been recommended by Food and Agriculture Organization of the United Nations (FAO) as one of the most efficient way to safeguard food security of the world.