cqvip:The introduction and use of foreign germplasms have played an important role in the improvement of crop varieties in China. Based on published materials and scientist interviews,we collected data on the sown area,morphological characteristics,and pedigree of the popular rice varieties grown in the 15 major rice production provinces and 1 autonomous region in China,from 1982 to 2011. Results showed that China's scientists developed the largest number of rice varieties worldwide,and that rice yield potential and grain quality have substantiality improved during the studied period. In contrast,resistance of newly-released varieties to diseases and insect pests has decreased since the 1990 s. Germplasms from the International Rice Research Institute(IRRI) and from Japan have contributed 16.4 and 11.2% of genetic materials to China's rice varieties developed between 1982 and 2011,respectively. While IRRI's materials contributed to the improvement of yield potential,growth duration,and blast and bacterial blight resistance,Japanese materials contributed to the improvement of grain quality. Materials from other countries contributed to the improvement of resistance to diseases and insect pests,particularly to rice blast disease,brown planthoppers,white-backed planthoppers,and striped stem borers.
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