Cheng, B., Rakow, G., Olson, T., Williams, D. J. and Gugel, R. K. 2015. AAC Adagio yellow mustard. Can. J. Plant Sci. 95: 1043-1045. Mucilage content in yellow mustard (Sinapis alba L.) is an important seed quality parameter for the mustard trade since mucilage contributes to the consistency of prepared mustard products. Some wild type brown-seeded accessions of S. alba have much higher mucilage contents than have been observed in yellow-seeded cultivars and breeding lines. Increasing the mucilage content of cultivated, yellow-seeded S. alba by transferring the high mucilage trait from brown-seeded S. alba was initiated in 2004 at the Saskatoon Research Centre, Agriculture and Agri-Food Canada. The yellow mustard variety AAC Adagio with high mucilage content [96.8 centistokes (cst) g^-1 seed] was successfully developed from crosses between the elite yellow-seeded breeding line SA00-PYM (mucilage: 35.2 cst g^-1 seed) and five brown-seeded S. alba accessions (mucilage: 87.5-108.7 cst g^-1 seed). AAC Adagio is well-adapted to all mustard growing areas of western Canada.