Maize is the most widely grown grain crop throughout the world. Specific maize strains have been genetically engineered to express agriculturally desirable traits, including resistance to pests and to herbi cides. GM maize MON87427 has the characteristics of glufosinate herbicide tolerance and is one of the most commonly used strains in processed food and feed. 

This programme aimed to demonstrate the capability of participant’s real time PCR or digital PCR capabilities in determining GM target gene contents including the GM gene and the endogenous gene. The copy number ratio or mass fraction of event specific sequence and endogenous gene of two GM maize samples with unknown GM content were to be determined by the participants. 

The reference values provided by the National Institute of Metrology (NIM), China in the test samples were used as the assigned value for evaluating measurement results of participants. The relevant Calibration and Measurement Capabilities (CMCs) of NIM are registered in the Key Comparison Database (KCDB) which was created by the Bureau International des Poids et Mesures (BIPM, International Bureau of Weights and Measures) in relation to the Comité International des Poids et Mes ures (CIPM, International Committee for Weights and Measures) Mutual Recognition Arrangement (MRA).