We offer ASReml as a standalone package or ASReml-R for use within the R environment.
Both are powerful tools for fitting mixed models and are based on the same computational core, although new developments occur first in the standalone version.
ASReml standalone uses a text file user interface and can access more work-space, making it useful for very large problems. ASReml-R is convenient for regular users of the R environment and it is easier to manipulate data.