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Since the end of 1940s,China has ever taken breed-ing and popularization of elite varieties as the im-portant measures for yield increase of rice.About1,000 varieties and 100 hybrid rice combinationshave been developed,among which 284 ones haveonce been cultivated over an annual area of667,000 ha.There have been several
Since the end of 1940s, China has ever taken breed-ing and popularization of elite varieties as the im-portant measures for yield increase of rice. About1,000 varieties and 100 hybrid rice combinationshave been developed, among which 284 ones haveonce been cultivated over an annual area of667,000 ha.There have been several