Expanding the environmental coverage of high yield technology.

Cultivated rice evolved from wild rices found growing along river estuaries. As a taste for cereal developed, cultivation began and migration of the early cultivators accelerated the evolution of cultivated forms adapted to different environments. Today most rice is cultivated under controlled irrigation. In several developing countries it is also grown in a variety of difficult environments where drought, soil fertility, insects, diseases, and mineral toxicity are important constraints. Most international research efforts have been concentrated on irrigated rice. But recently, more attention began to be paid to problems in the more difficult environments. Here we report some aspects of the Brazilian experience on upland rice, which indicates that technology can increase yields and reduce instability, and that under difficult environments, upland rice can be a stable and profitable source of food. Brazil produces about 9 million tonnes of rice yearly; 70% from upland and the rest from irrigated land. Total cultivated area varies from 5 to 6 million hectares