Genetic diversity of the 18 alfalfa local varieties in China and the 9 alfalfa varieties representing the 9 alfalfa basic germplasm sources in North America were studied using RAPD markers.Resultsshowed that: Obvious polymorphisms within and among varieties can be revealed by amplifying individula DNA samples. Meanwhile, polymorphisms within varieties are concealed, and among varieties are obviously reduced,when using bulk samples.7 primers reveal total of 52 loci,and all the loci are scored as 1 forpr...