Beneficial analysis on introduced rice germplasm from abroad in China.

Since 1949,more than 9963 varieties and entries of foreign rice germplasm have been introduced into China for evaluation and utilization. Among of which,22 and 81 introduced varieties were annually planted over 66 700 hectare and 6 670-66 700 hectare each in some years,respectively. There were 33 most important rice hybrids derived from foreign cytoplasmic male sterile and/or restorer descents with the largest annual planting area more than 0.4 million hectare each in a certain period. Besides,a large number of elite foreign rice materials have been utilized as cross bone-parents in various breeding programs,from which more than 2000 new varieties have been created and released for cultivation during the pasted 60 years. The statistical analysis indicated that more than 77.3 million tones of rough rice had been increased due to direct and/or indirect utilization of these introduced foreign rice varieties/materials,showing significant benefits both in economic and social domains. Therefore,strengthening introduction of foreign rice germplasm is one of the agricultural strategies to enrich cultivar′s genetic diversity in rice improvement,and to increase rice production for food security in China.