Concepts and strategies for plant adaptation research in rainfed lowland rice

Stable and high yields of rainfed lowland rice are important for food security in many of the subsistence farming systems in Asia. Progress in breeding for higher yields has been slow. Improving the adaptation of rainfed lowland rice to the range of abiotic stresses encountered in these drought-prone systems has been advocated as the basis of a breeding strategy to increase the rate of genetic improvement of yield. Putative adaptive traits have been nominated and studied. However, there is little consensus on the definition of appropriate trait-based selection criteria to complement direct selection for yield. The complexity of the target population of environments, and the incidence of large genotype-by-environment (G x E) interactions, has stimulated interest in analysis and interpretation of yield variation in multi-environment trials as part of the process of examining the adaptation of rainfed lowland rice. The rationale underlying analysis of adaptation is examined from the perspective of facilitating selection decisions within rainfed lowland rice breeding programs. (C) 1999 Elsevier Science B.V. All rights reserved.