Simulation of genotype performances across a larger number of environments for rice breeding using ORYZA2000

Breeding line selection with conventional field methods is limited by time, cost, and appropriate environments. Crop models can be used as a tool to assist in breeding line selection by extrapolating the results of multiple-environment trials (MET) to large environments in a cost-effective and faster manner. This study is the first attempt to use ORYZA2000 for the selection of drought-resistant rice genotypes, and it provides a 'virtual' platform for a large number of environmental trials. In a case study, ORYZA2000 results from two field experiments in two environments were extrapolated to 669 environments in South Asia. For these two field experiments, the differences between simulated and field-measured grain yield and total above-ground biomass for all the 69 genotypes were within the standard deviations of the field measurements. This result confirmed that ORYZA2000 has the capability to correctly represent the growth and yield of rice genotypes under different environments. Using simulation outputs for 69 genotypes in 669 environments, the performance of these genotypes was evaluated for rainfed conditions with various drought stress. With the increase in the number of environments, the effect of the genotype on phenotypic performances across environments become much more significant than that of the effects of environment and genotype-environment interactions, and heritability was also increased. Desirable rice genotypes could then be selected by breeders based on the expected yield and adaptability to various environments generated by the model. The evaluation of rice genotypic performance by ORYZA2000, as 'virtual' multiple-environment trials, can improve the reliability of selected genotypes for a wide range of environments and enhance efficiency in terms of time consumption and cost effectiveness of the breeding process. (C) 2013 Elsevier B.V. All rights reserved.