Genetic diversity of aphidresistant alfalfa varieties/lines based on SSR markers

Six SSR markers were used to investigate the genetic diversity of 9 different aphidresistant alfalfa varieties/lines. The loci of 69 were detected, 63 loci of which was polymorphism. The rate of polymorphism was 91.3%, the average number of allele was 1.913 0, the average number of effective allele was 1.482 2, the average index of genetic diversity was 0.293 4 and the genetic distance ranged from 0.156 6 to 0.623 2. The results of clustering analysis showed that M8 was more close to HA-3 and their similarity coefficient was the highest (0.855 0). The similarity coefficient between S7 and X2 was the lowest (0.536 2). In addition, the similarity coefficient between high aphidresistant variety (HA-3) and low aphidresistant variety (Hunter River) was 0.739 1, which suggested that their genetic background was remarkably different.