Opportunities for and challenges to improving hybrid rice seed yield and seed purity

摘要

After success in China, more than 20 countries worldwide have started hybrid rice programs and about 40 rice hybrids have been released for commercial production. Hybrid rice seed production area and yield have increased rapidly as hybrid rice growing area expanded in many countries. Seed yield in China has reached 2.5.2.7 t ha.1 and about 1.1.5 t ha.1 outside China in commercial seed production plots. The world hybrid rice growing area should increase to 19.20 million ha in 2005, of which 16.5 million ha are in China and the rest outside China. The total area for F1 seed production and parental line multiplication should reach 123,400 ha in China and 35,000 ha outside China. Considering the Chinese experience, there are tremendous opportunities to improve hybrid rice seed yield and seed quality. The challenges to improving hybrid rice seed yield and seed quality are (1) establishing a suitable system for parental line multiplication and purification,F1 seed production, and quality control; (2) finding the best sites and season for large-scale seed production; (3) training seed growers to increase their skills and experience; (4) refining seed production techniques locally;(5) improving field management approaches, including agronomic and pest control; (6) developing seed parent lines with a high outcrossing rate and resistance to major pests; (7) purifying existing parental lines; and (8) setting up national purity or quality standards for hybrid rice seed production. International cooperation and the extensive participation of public, private,and nongovernment organization sectors in hybrid rice seed production and marketing would contribute toward both food security and additional rural employment in rice-growing countries.