2011 Volume 80 Issue 1 Pages 1-12
Current status of research on improvement of drought resistance in rice is reviewed. Contribution of the past breeding programs to yield increase has been confirmed in various rainfed crops such as corn, wheat, oat and upland rice. Consultative Group for International Agricultural Research (CGIAR)(e.g., International Rice Research Institute) and governmental institutes of India, Thailand, and China are currently (2009) conducting breeding for improvement of drought resistance in rice. In the Mekong region, rice breeding based on the analysis of interactions among the target environments in multi-location trials is in progress, in order to improve broad adaptation in rainfed lowland rice. In the Philippines and Eastern India, higher yielding lines and cultivars have been developed by using direct selection of high-yielding lines under managed drought conditions at flowering time in the dry season. Various putative drought resistance traits, including drought avoidance by root system traits, have been evaluated, and several chromosome regions of clusters of their quantitative traits loci (QTL) have been listed. A deeper rooting cultivar with earlier maturity and higher yield was released in India by marker-assisted selection. Drought resistance genes were identified to be co-located in the putative QTL regions. Transgenic rice lines with over-expression of stress responsive transcriptional factors and/or drought resistance genes were evaluated in field experiments. Phenotyping is essential in drought improvement research even in molecular biological approaches, which leads to construction of high through-put phenotyping platforms and plant phenomics research.
