A spring oat developed by the Cereal Research Centre (formerly Winnipeg Research Centre) in Winnipeg, Manitoba. It bears the accession number W86120 and OT255 and was tested in the Western Oat Co-op Test from 1988 to 1990. AC Marie was licensed by the Food Production and Inspection Branch in 1991.

AC Marie originated from the cross CI4492 / OT244 // OT233.

AC Marie is a high yielding oat. Based on three years of testing in the 1988-90 Western Co-operative Oat Tests, AC Marie has shown that it yields more than Dumont or Calibre. In other agronomic characteristics, it is similar to Dumont. Its lodging is equal to Dumont, it matures less than one day later than Dumont and it is slightlyl taller than Dumont.

Like the well accepted oat variety Dumont, this new cultivar is resistant to stem rust, crown rust, and loose and covered smut. Its moderate level of tolerance to BYDV is greater than that of Dumont but less than that of the BYDV tolerant oat variety Robert. This level of virus tolerance is likely due to this line's having been grown and selected in the New Zealand winter nursery.

AC Marie has a very thin, white hull. It is the first oat variety in western Canada combining the low percent hull (previously associated only with the tan coloured hull) with a white coloured hull. Until now, low percent hull was associated only with the tan coloured hull. AC Marie has a long kernel. Its kernel weight is less than that of Robert but only slightly less than Dumont. Its kernel is not as plump as Dumont and Robert but is similar to Riel. The protein content of AC Marie is less than that of Robert but is similar to that of Dumont and Calibre. The main weakness of AC Marie is that its test weight is lower than that of Dumont. This lower test weight is likely due to long, narrow kernel shape of AC Marie. The oil content of AC Marie is higher than that of any other common oat variety recommended for Canada; high oil content is associated with high energy content.

AC Marie is named after Marie Anne Gabourie who was the first white woman to settle in the Red River settlement and in the Canadian Northwest. She married a fur trader Jean Baptiste Lagimodiere, and in 1808 gave birth to the first white chile officially recorded in the Canadian Northwest. She was also the grandmother of Louis Riel.