Abstract:The ecological adaptability of rice varieties to the diverse environments is closely associated with the yield andlocal-adaptability. In order to identify the rice varieties with strong adaptability, 284 historic and modern rice varieties, which were collected from Heilongjiang, Jilin, Liaoning, Ningxia, Xinjiang of China and Japan, were deployed to clarify the phenotypic variations under multiple environmental conditions. Seven agronomic traits including days to heading, plant height, panicle length, panicles per plant, grains per panicle, seed setting rate and 1000-grain weight were determined at six identification sites (Shenyang, Beijing, Yinchuan, Linyi, Nanchang and Sanya). The phenotypic variations of these agronomic traits were visible at diverse locations. For instance, the phenotypic values were constantly decreased from Shenyang with higher latitude to Nanchang with lower latitude, but they were increased in Sanya winter environment. In relative to the varieties in years-I that were released before1960, the modern cultivars in years-IV (released after2000) showed the prolonged growth period, the reduction of plant height and panicle number, the elevation of grains per panicle, as well as no significant differences on seed setting rate and 1000-grain weight. Overall, the rice traits changed from multi-panicle type to large-panicle and heavy-panicle type. The genetic relationships among the varieties from Heilongjiang, Jilin and Japanwere relatively closer, while that between varieties from Liaoning and other regions including Heilongjiang, Jilin and Japan were relatively further. The genetic relationship between the varieties in years-II (released during 1960-1970's) and years-III (released during 1980-1990's) was relatively closer, followed by that between the varieties in years-II, years-III and years-I, and that between the varieties in years-IV and other years' were relatively further. Under multiple environmental conditions, the phenotypic values of 1000-grain weight, panicle length and panicle number were relatively stable, followed by days to heading, plant height, seed setting rate and grains per panicle. The stability parameter of days to heading was observed to be significantly positively correlated with that of plant height, panicle length and panicle number. The stability parameter of plant height was positively related to that of panicle length, grains per panicle and 1000-grain weight. The stability parameter of days to heading in varieties released over decades was variable (years-I >years-II >years-IV >years-III). An improved ecological adaptability was observed in the modern varieties, in contrast to the historical varieties that were released few decades ago. Twenty varieties (e.g. Liaojing 931, Liaojing 454) showed better local-adaptability under multiple environments, thus being valuable in breeding for new rice varieties with broad adaptability.