About MET

The ecosystem based breeding programs of IRRI have been constant and reliable sources of new
and elite rice varieties beginning with the 'miracle rices' that ushered in the Green Revolution in the 1960s. To date, IRRI breeding lines have been released as 864 new varieties in 78 countries.

IRRI breeding programs generate fixed and stable lines each season that are identified from observational and replicated yield trials. Elite lines are then advanced to multi-environment testing (MET) conducted via breeding networks for rainfed lowland, drought, and submergence. In most cases, the basis for promoting lines to the MET is the performance at a few sites, at times in Los Baños only. Moreover, the current breeding networks have limited geographical coverage and face challenges in terms of germplasm movement. A systematic and exhaustive evaluation of these fixed and stable lines, sequentially and early on in the varietal development pipeline, is needed.

Expanding the testing mechanism of IRRI breeding lines to involve more key sites would enable breeders to select for wide adaptation and exploit favorable genotype (G) x environment (E) interactions. Using the INGER mechanism to anchor such a sequential, multistage, and multisite approach would simplify seed processing and movement using long-established protocols. Disseminating more breeding lines to key sites will allow NARES breeding programs to use early generation materials in local varietal improvement, generate valuable feedback, and ultimately enable the deployment of breeding products to specific environments and markets.


To establish a systematic, sequential, multistage, and multi-environment testing (MET) system for elite rice lines in order to improve overall breeding efficiency.

  1. To identify elite lines with high and stable yields and wide adaptation across a target population of environments.
  2. To select superior materials adapted to specific environment(s) and agro-ecologies.
  3. To deploy varieties and breeding products to specific market segments.
  4. To exploit G, E, and GxE interactions in releasing breeding products to one or more target environments.
  5. To generate earlier feedback on trait performance and identify trait packages for molecular breeding.
  6. To improve partnerships with public, NGO, and private sectors on rice variety development.