Wide adaptability of new rice cultivars developed by the Japan-China collaborative project in Yunnan, China

China's Yunnan Province is considered to be one of the centers of genetic diversity in Asian cultivated rice. A collaborative research project between JIRCAS and YAAS for lowland japonica rice breeding using a wide diversity of genetic resources has been conducted in Yunnan since 1982. New rice cultivars developed through the joint project have been grown widely in and around the province since 1989. In 1997, the total area of these cultivars covered more than 200,000 ha, accounting for more than 40% of the japonica rice-growing area and about 20% of the total rice-growing area in Yunnan.