Alfalfa, Medicago sativa, and M.arborea are autotetraploids (2n=4x=32) assumed reproductively isolated until 2003.Then, an alfalfa genotype was identified in Wisconsin that produced a few seeds and progeny with hybrid traits after a large number of pollinations by M.arborea.At the same time in Australia, a derivative of this alfalfa genotype also produced a low frequency of progeny with hybrid traits.Thus, the hybridization barrier was weakened by selection of parents.Hybrids from both events expressed traits from M.arborea, and M.arborea-specific DNA bands.More of the M.sativa genome was retained, based on the DNA results; nonetheless, there was considerable genetic transfer from M.arborea.To date, more than 35hybrids with an array of M.arborea traits have been obtained.Traits have been genetically transmitted in crosses with alfalfa, and hybrids have been crossed with each other to pyramid selected M.arborea traits.The latter material needed an identifying name for ease of recording and reporting.Alfalfa and M.arborea were abbreviated and combined for the name Alborea.The characteristics of Alborea, and its anticipated uses will be described.