Abstract: To investigate the rules and present situation on the development of first-cropping two-line hybrid rice in Yangtze River Area, the data of cultivar registration and promotion area during 1998-2015 were collected and analyzed. The results showed that: 1) the first-cropping two-line hybrid rice was getting more and more important due to its increasing planting area in the Yangtze River Region. Up to the end of 2015, a total of 139 first-cropping two-line hybrid rice combinations had been registered. Among them, 26 combinations were registered by the National Crop Variety Examination and Approving Committee, and 5 combinations were titled “Super Rice”. 2) According to the Ministry of Agriculture statistics, during 1998 to 2015, there were 76 first-cropping two-line hybrid rice combinations which had promotion area equal to or more than 6 700 hm², with an accumulative promotion area of 7 531 000 hm². Hunan, Hubei and Jiangxi were the main first-cropping two-line hybrid rice growing provinces, with an accumulative promotion area of 6 974 000 hm², accounting for 92.6% of the total promotion area. 3) The seeds companies played the most important role in the breeding and promotion of first-cropping two-line hybrid rice, the cultivars from which had an accumulative promotion area accounting for 41.6% of the total promotion area. The breeding organizations from Hunan Province made the greatest contribution, whose cultivars were widely popularized in Hunan, Jiangxi and Hubei, with an accumulative promotion area of 5 887 000 hm². Present thesis introduced the stat quo of cultivar registration and extension of two-line early hybrid rice in Yangtze region, analyzed the contribution of the major sterile lines and their genealogical links, and finally proposed the disadvantages and countermeasures for the development of frist-cropping two-line hybrid rice in Zhejiang Province.

Key words: Yangtze River Area, frist-cropping two-line hybrid rice, promotion area, sterile lines, genealogical links