The IRTP started as a project when it was first approved by the United Nations Development Programme in January 1975, for a period of five years with funding support of US$2.0 million. In its second phase, INGER was extended for 1980-84 with a grant of $7.8 million from UNDP, and renamed as the International Rice Testing and Improvement Program (IRTIP). IRTIP had greatly expanded work plans, including germplasm collection, cooperative research networks on innovative techniques for rice breeding, and biological nitrogen fixation. The next phase of the project (1985-90) was also funded by the UNDP. During 1991-98, the UNDP continued its funding as component III of the Global Program entitled .Development of technology which has less dependence on synthetic fertilizers and agrochemicals. Various donors showed up but with decreasing support.the World Bank; Swiss Agency for Development & Cooperation; and Federal Ministry of Economic Cooperation/German Agency for Technical Cooperation (GTZ). In 1992, INGER merged with the Genetic Resources Center (GRC) because of downsizing, and, in 1998, INGER was primarily supported by IRRI unrestricted funds. The Council for Partnerships on Rice Research in Asia became the network's steering committee in 1999 and started to gather strength from the network's partners. In 2002, INGER was transferred under the Plant Breeding, Genetics, and Biotechnology Division (PBGB), and became an integral part in seed exchange and germplasm distribution.

Over the years, INGER has become a regular component and a constant reliable source of elite breeding material for NARES and IARC rice improvement programs. On average, about a thousand genetically diverse materials contributed by NARES and IARC scientists are evaluated yearly under different rice ecosystems, and biotic and abiotic stresses. More than 600 experiment stations in 80 countries participate in these annual evaluations.