Effects of drought stress during reproductive stages on grain yield and quality of different genotypes in rice (Oryza sativa)

摘要

With fast economic development and urbanization, China is facing a serious crisis of water shortages. The estimated annual loss to the national economy from water shortage reaches more than $25 billion in China (Deng, 1999). Rice production alone consumes about 50% of the water resources in China. There is an urgent need for reducing water consumption in rice production. Traditionally, the Yangtze River basin is the major rice production area (70% of the total) in China. Although the wet monsoon brings ample rainfall to Yangtze basin in most years, its arrival date and duration are unstable. The rainfall is erratic and frequently causes drought and/or flooding in this area. Drought has been the single most devastating factor that affects rice production (Lin, 1996). Drought in summer is prevailing and drought stress often occurs at the reproductive stages of the rice crop. Drought tolerance is a complex trait that involves numerous aspects of developmental, physiological, biochemical, and molecularadjustments (Blum, 2002). Therefore, it is essential to understand the effects of the prevailing drought stress in the target environment on both the yield and quality traits in order to undertake the genetic improvement of drought tolerance of the rice cultivars for this region.