A comprehensive data collection for maize. Optimas-DW integrates data from different data domains such as transcriptomics, metabolomics, ionomics, proteomics and phenomics. A web interface allows users to browse through all stored experiment data in OPTIMAS-DW including all data domains. Furthermore, the user can filter the data to extract information of particular interest. All data can be exported into different file formats for further data analysis and visualisation. The data analysis integrates data from different data domains and enables the user to find answers to different systems biology questions. Finally, maize specific pathway information is provided.