Technical Abstract: 'Cache' meadow bromegrass cultivar [Bromus riparius Rehm.] is recommended for use on irrigated and semi-irrigated pastures for forage prduction. The parental germplasm for Cache was derived from selections within PI 578532 ('Regar'; 20.9%), PI 536012 ('Fleet'; 54.1%), and PI 536013 ('Paddock'; 25%). This cultivar is the result of two cycles of recurrent selection for increased forage yield, total seed yield, 100-seed weight, and seedling emergence from a 7.6 cm planting depth. Morphologically, Cache is significantly taller, with longer flag leaves that are oriented higher on the culm than the cultivar Fleet. Cache meadow bromegrass has a chromosome number of 2n=10x=70, which is the same as Regar, Fleet, and Paddock. Based on amplified fragment length polymorphism profiles, Cache meadow bromegrass displayed a relatively large number of DNA fragments comparable to meadow bromegrass cultivars Fleet, Paddock, Montana, and MacBeth. Under a line-source study, with irrigation rates that ranged from 10.1 to 36.8 mm per week, Cache meadow bromegrass produced significantly more dry matter than the cultivar Fleet at all irrigation rates and significantly more dry matter than the cultivar Regar at the two lowest irrigation rates. Under repeated defoliation Cache meadow bromegrass yielded significantly more total dry matter than orchardgrass (Dactylis glomerata L.) cultivars Ambassador and Latar on an irrigated site in northern Utah. When combined across six locations and three years in the Northern Plains Regional Trials (NPA), Cache meadow bromegrass produced significantly more dry matter forage than cultivars Regar and Fleet meadow bromegrass, Paiute orchardgrass, and Manchar smooth bromegrass (Bromus inermis L.). Across locations, Cache meadow bromegrass was similar to Regar in establishment and persistence, but significantly better than Fleet.