Effects of warming and autonomous breeding on the phenological development and grain yield of double-rice systems in China

Development of successful strategies to alleviate adverse impact of climate change on crop production relies on understanding of interactions between climate and crop physiology, and presents a new opportunity for sustainable agriculture. In this study we combine the analysis of 30 years of climate data and observed rice data with crop modeling to investigate the impact of climate change and changes in rice varieties on rice growth and grain yield from 1981 to 2009 at three sites (Nanchang, Hengyang and Gaoyao) in double rice regions in China. The results revealed that while there was a warming trend in general, significant warming mainly occurred before jointing stage of early rice and after jointing of later rice. The adoption of new rice cultivars could only partly mitigate the negative impact of warming on rice growth duration and biomass growth. However, the changes of varieties increased the grain yield of both early and late rice through increased harvest index. The major variety changes involved reduced intrinsic earliness, extended grain filling period, and improved harvest index. In the face of future climate change, a planned breeding effort is needed to maintain or increase grain yield of the double rice system.