Developing Climate Change-Ready and Low-Input Adapted Rice Varieties for Temperate Regions

Increasing production cost relating to fertilization and irrigation are two of the main constraints in rice production. Moreover, the unpredictable weather patterns and the increasing mean annual temperature due to climate change are limiting the yield potential in rice especially in temperate regions. It is therefore essential to develop rice varieties which are climate-change ready and with high yield potential even under conditions of low input. Using molecular breeding, we have been developing temperate rice varieties with introgressions of Pup1-OsPSTOL1 (Gamuyao et al. 2012, Nature) for enhanced early-root vigor to enhance Phosphorus (P)-efficiency use under conditions of low P input and rainfed. In IRRI, Philippines, we conducted QTL mapping for yield-elated traits under low P and low water input. Using 137 indica × japonica recombinant inbred lines (RILs), we have identified 4 QTLs for panicle length on chromosomes 1 (pl01), 2 (pl02), 9 (pl09), and 11 (pl11), under rainfed conditions and low phosphorus (P) input. These QTLs were not identified in temperate region (Korea) which suggests that these QTLs are specific in tropical conditions. Interestingly, QTLs for yield components were collocated with the pl QTLs. We are now developing NILs with various combinations of these 4 pl QTLs to confirm and fine-map the important genomic regions. The yield advantage under low P and low water input of the developed lines versus lines without introgressions of QTL/gene is presented on this poster.