International Rice Research Institute (IRRI), Soil Science/Agronomy, The Philippines
About one billion people depend on rainfed rice grown on 50 million hectare in South and Southeast Asia. Farmers in these environments face various bio-physical stresses resulting in low and unstable yields (2.1 versus 5.8 t ha-1 for irrigated systems in 1997-9) and are among the poorest in Asia. The most important abiotic constraints to production are regular droughts and unfavourable soil conditions (low soil fertility, toxicities).
Contrary to the developments in irrigated systems, successful introduction of modern rice varieties is rather recent in rainfed environments. Their main advantages are higher yields, better response to fertilisers, lower susceptibility to diseases, and shorter durations. Further varietal improvement for the adaptation to abiotic stresses can be expected through the use of recently discovered major quantitative trait loci (QTLs) combined with marker assisted selection tools. These developments offer considerable opportunities for a moderate intensification of rainfed systems, they can contribute to reduced production risk, and new possibilities for diversification are created. But to reach these goals, the variety-driven changes must be accompanied by improved/adapted crop and natural resource management options to maintain the productivity and sustainability of rainfed lowland systems.
Productivity increases will not only benefit the generally poor rainfed farmers, but could contribute an important share to the necessary rice production increases needed in the near future to compensate population growth rates and loss of prime farmland. Water use efficient and highly productive rice production technologies will become increasingly important in the near future due to a growing competition for available water resources and possible adverse weather conditions caused by global climate changes.
Keywords: Asia, Productivity, Rainfed lowlands, Rice, Risk reduction