Northeast Research and Demonstration Farm
Most germplasm used in alfalfa cultivars in the north central region of the United States is purple flowered and referred to as sativa. Yellow-flowered (falcata) alfalfa is an unadapted germplasm that has made few contributions to the current cultivars. However, our previous research has shown that sativafalcata crosses (SFC) produce greater yield than sativa-sativa crosses (SSC). This indicates that falcata has favorable genes for yield and that the use of falcata may help improve yield in new cultivars.
Iowa State University
Li, Xuehui and Brummer, E. Charles, "Improving Alfalfa Yield Using Unimproved Germplasm" (2006). Iowa State Research Farm Progress Reports. 1098.