About 17 million hectares of upland rice are grown annually worldwide, with 10.5 million ha in Asia, 3.7 million ha in Latin America, and 2.8 million ha in Africa (IRRI 1993). Total upland production is about 20 million tons. Rice is a major staple crop for upland farmers in many parts of Asia, Africa, and Latin America. The total area supporting upland rice-based cropping is considerably larger because of rotation with fallow and other crops. The crop is grown alone or in diverse mixtures in shifting or permanent fields under a wide range of conditions of climate, slope, and soil type, often as a subsistence crop receiving few purchased inputs, although it is commonly a commercial crop receiving inputs in favourable areas such as Brazil, Indonesia, and the southern Philippines. Reported upland rice areas have remained stable or have increased in some countries, including the major Asian producers Bangladesh, India, and Indonesia, but have declined for others such as Thailand, the Philippines, and Myanmar (Table 1). Care needs to be taken, however, in interpreting upland rice area estimates, which can be unreliable. For example, the 1991 upland rice area in the Philippines was reported as 68,000 ha in the 1993 IRRI Rice Almanac (IRRI 1993), as 17 1,000 ha in the 1997 IRRI Rice Almanac (IRRI 1997), and as 126,000 ha by the Philippine Bureau of Agricultural Statistics (Pandey, unpublished 1997)