History and prospects of hybrid rice development outside of China

Abstract

Increasing rice production has always been a top priority in Asian countries. The research and development of hybrid rice has contributed significantly to global food security since the 1970s. Inspired by China’s success, many countries, specifically the South and South-East Asian countries, have started hybrid rice programs through introduction, adoption, and localization from the 1980s. Currently, about 20 million hectares of hybrid rice are being produced annually in the world, including 6.4 million hectares outside of China, mostly in the South and South-East Asian countries. The United States of America also became an important hybrid rice growing country since the 2000s. Different countries used various approaches and patterns of technology development and adoption. Planting areas of hybrid rice fluctuated yearly depending on technical adoption, seed supply, weather, and government policies. Adoption rates of hybrid rice in the major rice-producing countries are still low, which leaves great potential for further development. The main constraints for hybrid rice adoption in the tropics are low levels of hybrid heterosis, high price and lower quality of seeds, poor milling gain quality associated with high chalkiness and low head rice yield, low resistance to major pests, and poor education to farmers and unstable government policies. Recent progress of grain quality improvement made hybrid rice more acceptable by farmers and rice consumers. International Rice Research Institute has been playing a significant role in the development of tropical hybrid rice including extensive research, variety breeding and releasing, training and technology extension. Application of semi-dwarf rice varieties, so called the green revolution, has significantly increased rice production in Asia. Unfortunately, the common adaption of semi-dwarf germplasm originated from one source- germplasm homogenesis—might have also contributed to the reduction of germplasm diversity which makes less hybrid vigor and could be one of the main causes for low yield heterosis compared to the hybrid rice in the temperate regions. The concept and practice of heterotic grouping used in hybrid corn have not been applied to hybrid rice development. Recent progress made from the association of public institutes and seed industry has been beneficial to both investors and will support for the sustainable growth of hybrid rice in the future. New challenges such as cultural practices, climate change, market demand, management of intellectual property, and the application of gene transformation technologies require a close collaboration among scientists, farmers, policy-makers, public institutes, and the seed industry.